Effect of Coffee Consumption on Hunger, Satiety, and Appetite-regulating Hormones in Women With Overweight or Obesity
Phase: NA
Conditions: Obesity
Sponsor: University of Guadalajara

 
 
University of Guadalajara 
Health Sciences University Center 
INSTITUTE FOR TRANSLATIONAL NUTRIGENETICS AND NUTRIGENOMICS 
 
 
 
 
 
 
 
 
Effect of Coffee Consumption on Appetite Traits in 
Overweight and Obese Woman 
 
  
 
 
January 2022 – August 2023 
 
 

1 
 
. General information 
 
a. Title 
Effect of Coffee Consumption on Appetite Traits in Overweight and Obese Woman 
 
b: Responsible researcher: Livier Nathaly Torres Castillo 
 
2. Abstract 
 
Background: There are studies suggesting that coffee could help in body weight control. The 
mechanisms by which coffee could help in weight control are unknown and it has been suggested 
that such effect is related to appetite control. In an investigation in which normal weight men 
participated, the effect of coffee consumption on the concentrations of peptide YY (an appetite 
suppressant) was analyzed and a higher concentration of this hormone was found 60 and 90 
minutes after the ingestion of decaffeinated coffee, as well as a lower sensation of hunger during 
the 180 minutes after coffee consumption. By performing three different interventions: instant 
coffee with 3 mg/kg weight of caffeine, decaffeinated instant coffee and water (control), it was 
observed that, 180 minutes after the caffeinated coffee intervention, participants reported a lower 
desire to eat compared to the other two interventions. However, other studies have not found a 
decrease in energy intake and appetite sensations when consuming caffeinated coffee, 
decaffeinated coffee, or caffeine capsules in normal weight women. In spite of the scientific 
evidence, there are few studies regarding coffee and its effects on hunger and satiety and even 
fewer studies carried out in women with overweight or obesity.   
Objective: To assess the effect of coffee consumption on hunger, satiety, appetite-regulating 
hormones, and dietary intake in women with overweight or obesity. 
Methodology: This is a crossover randomized clinical trial. Subjective appetite is assessed 
through visual analogue scales, and appetite related hormones ghrelin and cholecystokinin are 
measured with ELISA kits. Diet intake is evaluated with 3-day food records and coffee and caffeine 
products frequency questionnaire. Biochemical and anthropometric variables are also measured.  
Infrastructure: Is available the access to the “Instituto de Nutrigenética y Nutrigenómica” of the 
“Centro Universitario de Ciencias de la Salud” of the Universidad de Guadalajara. The institute 
has all the necessary equipment to perform biochemical determinations of appetite-regulating 
hormones (spectrophotometer, plate washer, plate shaker) and other analytes (centrifuge, 350 
chemistry glassware, refrigerators at different temperatures, all the necessary consumables such 
as tips, tubes, cryo boxes, etc.). On the other hand, there is a room to carry on the session with 
the participants, give them breakfast, apply the visual analogue scales, and take the blood sample.   
 
 

2 
 
3. Background 
 
There are studies that suggest that coffee could help in the control of body weight. To date, the 
mechanisms by which coffee could help in weight control are unknown and it has been suggested 
that such effect is related to appetite control (1). In an investigation in which men with normal 
weight participated, the effect of coffee consumption on the concentrations of peptide YY (an 
appetite suppressant) was analyzed and a higher concentration of this hormone was found in the 
60 and 90 minutes after the ingestion of decaffeinated coffee, as well as a lower sensation of 
hunger during the 180 minutes after coffee consumption (2). In another study in men and women 
with overweight/obese, it was found that the consumption of coffee with 6 mg/kg weight of caffeine 
at breakfast resulted in a consumption of 550 kcal less during the rest of the day compared to the 
control group (simple water consumption), but no differences in hunger and/or satiety sensations 
were observed (3). By performing three different interventions: instant coffee with 3 mg/kg weight 
of caffeine, decaffeinated instant coffee, and water (control), it was observed that, 180 min after 
the caffeinated coffee intervention, participants reported a lower desire to eat compared to the 
other two interventions (4). 
 
It remains uncertain which component of coffee influences appetite, but it has been observed that 
coffee abundant in chlorogenic acid has an effect on body composition. In a study conducted in 
overweight men and women who consumed instant coffee with 369 mg of chlorogenic acid and 
37 mg of caffeine for 12 weeks, it was found a decrease in visceral fat area, total fat area, BMI, 
body weight and waist circumference, compared to coffee consumption with 35 mg of chlorogenic 
acid and 38 mg of caffeine (5). However, other studies have not found a decrease in energy intake, 
appetite sensations, or gastric emptying when consuming caffeinated coffee, decaffeinated coffee, 
or caffeine capsules (6); therefore, more studies are needed to clarify these effects. 
 
Adding coffee as an extra ingredient of a food has shown effects on appetite. In a pilot study where 
the effect of cookies was analyzed, the main components were 5 grams of fiber and 1.9 grams of 
coffee grounds. It was observed that its consumption together with a breakfast of 1,160 kcal 
reduced appetite and food consumption at mealtime, hence, the researchers concluded that 
coffee grounds could have a positive impact on body weight control (7). Despite the scientific 
evidence, there are few studies regarding coffee and its effects on hunger and satiety and even 
fewer studies conducted in women with obesity.   
 
 
 

3 
 
4. Problem statement 
 
The prevalence of obesity has increased in recent years. The World Health Organization (WHO) 
has expressed its concern about this increase since it is estimated that in 2016 about 13% of the 
world's adult population had obesity and in the last 40 years its global prevalence has almost 
tripled (8). Obesity negatively affects the physiological functions of the body and forms a major 
threat to public health as it increases the risk of developing multiple diseases such as diabetes 
mellitus, cardiovascular disease, several types of cancer, a variety of musculoskeletal disorders 
and poor mental health, all of which have negative effects on quality of life, work productivity, and 
healthcare costs (9,10). 
 
In addition to these conditions, in obesity there is a reduced control of energy intake. The balance 
between energy intake and energy expenditure is controlled by complex neural networks within 
the central nervous system (CNS) that generate processes that inform about hunger and satiety, 
which are deregulated in people with obesity (11). Cholecystokinin (CCK), a hormone involved in 
these processes, is secreted by duodenal I cells and by central neurons in response to nutrient 
intake, mainly protein and lipid. On the other hand, in people with obesity, it has been observed 
that the ghrelin appetite suppression is affected and a dysregulated pattern in ghrelin secretion 
has been observed. Ghrelin is secreted by P/D1-type cells in the gastric fundus and increases 
appetite and food intake, but in people with obesity, reduced fasting ghrelin levels have been 
observed as a counter-regulatory mechanism for excess of body weight and, more importantly, 
subjects show uncontrolled postprandial ghrelin suppression (11). 
 
In recent years, the effects of coffee consumption on the modulation of hunger, satiety, and energy 
intake have been studied. In this sense, it has been observed that this beverage has an effect in 
the reduction of appetite, therefore, this could help in weight control (12,13). Regarding the effects 
of coffee on hormones involved in hunger and satiety, there are few studies that evaluate ghrelin 
and CCK concentrations in response to coffee consumption. Two studies on the effects of coffee 
on ghrelin concentrations were found; in them it was reported that this beverage did not cause 
significant effects on ghrelin concentrations and there was no relationship with hunger (2,4); 
however, these studies were done only in men (14), so it is necessary to know its effect in women. 
Another study did find that ghrelin concentrations decreased with coffee consumption compared 
to the levels in the washout period of the study; however, the limitation of this study was that it did 
not include a control group (15). On the other hand, it has been reported that coffee induced the 
release of CCK (16), however, in this last study the effect on hunger or satiety was not measured. 
Coffee is a very popular beverage, and its worldwide consumption is estimated at 168 million 60-
kilogram bags (17) and at the national level, Mexicans consume an average of two and a half cups 
a day (18). Nowadays, it is a challenge to find beverages that allow for successful nutritional 
interventions. Based on the above, the following research question has been proposed: What is 
the effect of coffee consumption on hunger, satiety, and appetite regulating hormones in women 
with overweight or obesity? 
 
5. Rationale 
 

4 
 
In the last 40 years there has been an increase in overweight and obesity worldwide in children 
and adults. In 2016, 650 million people in the world presented obesity and it is estimated that if 
this continues by 2025, one in five adults worldwide will present obesity (19). In Mexico according 
to the latest National Health and Nutrition Survey of the Middle Way (ENSANUT-MC, 2018) the 
prevalence of obesity increased from 32.15% in 2012 to 35.35% in 2018, in addition 75% of the 
Mexican adult population presents excess weight. In the case of premenopausal women, the 
prevalence of obesity in the age range of 30 to 49 years was 89% (20).  At the state level, Jalisco 
also showed an increase in the prevalence of obesity from 37.6% in 2012 to 39.8% in 2018 (20). 
 
Obesity also imposes a significant cost on health systems. According to a study conducted by the 
Mexican Institute of Competitiveness, it was calculated that the total costs of diabetes along with 
obesity amount to be more than 85 billion pesos per year; of this, 73% corresponds to medical 
treatment expenses, 15% to loss of income due to absenteeism from work and 12% to loss of 
income due to premature mortality. The cost of various medical complications for a person with 
obesity and prediabetes, if he or she does not change his or her lifestyle habits, can reach 1.9 
million Mexican pesos over 30 years. However, if the person modifies his or her lifestyle, in 30 
years the total expenditure would decrease to only 92,860 Mexican pesos (10). Therefore, 
preventing and treating obesity early, as well as seeking and finding supplements that suit the 
patient to execute more effective nutritional interventions, has economic benefits for the individual 
patient and for the health system in general. 
 
In the search of supplements to implement effective nutritional interventions to combat this 
problem, we found coffee. This beverage is highly consumed in Mexico since the average Mexican 
consumes two and a half cups a day (18). Recently, this beverage has caused great interest 
because there have been recent findings suggesting that coffee has an effect on appetite control 
which could help in weight control (3,4). Studying the effect of coffee on hunger and satiety in 
humans will contribute to generate knowledge for future nutritional treatments, will allow 
preventing the development of obesity, will provide a complementary option for a nutritional plan 
for patients who are already overweight or with obesity, and will be useful to give nutritional 
recommendations based on scientific evidence. According to our scientific search, so far only two 
studies have reported information on the effects of coffee in women with obesity. Both included 
the combination of overweight and obese women and did not measure any hormone involved in 
hunger or satiety, and in one of them they did not give coffee, but an extract of this beverage 
(3,13). For this reason, this study will be important to contribute to the knowledge gaps that exists 
regarding the effects of coffee on hunger, satiety, and appetite regulating hormones in women 
with overweight or obesity who are within one of the age ranges (30 to 49 years) with a high 
prevalence of obesity in Mexico (20). 
 
 
 

5 
 
6. Objective 
 
a: General objective 
To assess the effect of coffee consumption on hunger, satiety, appetite-regulating hormones, and 
dietary intake in women with overweight or obesity.  
 
b: Specific objectives 
1. To describe the demographic, anthropometric, biochemical, and dietary characteristics of 
the study sample. 
2. To compare the sensations of hunger and satiety at times t=-30 min, t=0 min, t=30 min, 
t=60 min, t=90, t=120, t=150 min and t=180 min between the two interventions: coffee and 
simple water. 
3. To compare the serum levels of cholecystokinin and ghrelin at times t=-30 min, t=0 min 
and t=180 min between the two beverage interventions (coffee and simple water). 
4. To compare the change (t=180 - t=0) in hunger and satiety sensations between the two 
beverage interventions (coffee and simple water). 
5. To compare the change (t=180 - t=0) in cholecystokinin and ghrelin concentrations 
between the two interventions (coffee and simple water). 
 
7. Hypothesis 
Coffee consumption decreases hunger and ghrelin, increases satiety and cholecystokinin 
concentrations, and changes energy intake in women with overweight or obesity. 
 
8. Methodological design 
 
a. Type of study 
Randomized crossover clinical trial. 
 
b. Research location 
Instituto de Nutrigenética y Nutrigenómica Traslacional (INNUGET) of the Centro Universitario de 
Ciencias de la Salud of the Universidad de Guadalajara. 
 
c. Study period 
The scientific literature review phase began in September 2020 and the study is expected to 
conclude in April of 2023. 
 
d. Inclusion and non-inclusion criteria 
 
Inclusion criteria 
• 
Women between 20 and 40 years old 
• 
Body mass index between 25 to 40 kg/m2  
• 
Regular menstrual cycle of 25-32 days in the last 3 months  
• 
Moderate coffee consumption (2 cups per day) 
• 
Having the habit of eating breakfast 

6 
 
• 
Availability of time in the morning 
 
Non-inclusion criteria 
• 
Use of any type of contraceptives in the last three months 
• 
Consumption of hypoglycemic, lipid-lowering, weight-loss, appetite altering and psychiatric 
medications 
• 
Diagnosis of diabetes mellitus, hypertension, cancer, polycystic ovary syndrome, 
hypothyroidism, hyperthyroidism, infectious diseases (influenza, COVID-19, etc.), renal 
disease, dysgeusia, or gallbladder disease 
• 
Weight loss ≥5% of their body weight in the last 6 months 
• 
Consumption of more than 20 g of alcohol per day 
• 
Smoking 
• 
Being pregnant or breastfeeding 
• 
Being vegetarian or vegan 
 
e. Exclusion criteria 
• 
Incomplete data and/or measurements 
• 
Individuals that decide to leave the study 
 
f. Sample size 
 
The sample size was calculated using the formula for comparing two means with data previously 
reported by Douglas BR et al., who reported a significant difference (p<0.01) in CCK 
concentrations when drinking 165 ml of regular coffee versus drinking 165 ml of NaCl water (16). 
𝑛= 𝜎12 + 𝜎22
(𝑥1 −𝑥2)2 (𝑍1−𝛼2
⁄ + 𝑍1−𝛽)
2
 
 
 
n = sample size 
α = 0.05 Z1-α/2 = 1.96  
β = 0.2   Z1-β = 0.842  
x1 = pmol/L of CCK when consuming regular coffee = 2.8 
x2 = pmol/L of CCK when consuming water containing NaCl = 0.4 
σ1 = standard deviation when consuming regular coffee = 2.2 
σ2 = standard deviation when consuming water containing NaCl = 0.2 
 
Substituting these values in the formula, an “n” of 7 subject per intervention was obtained. 
 
𝑛= 2.22 + 0. 22
(2.8 −0.4)2 (1.96 + 0.842)2 =  7 
 
 

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In addition, as reported by Horner et al., the sample size to detect a 20 mm difference in visual 
analog scales to assess appetite between meals (post-breakfast - pre-breakfast) in a paired 
design with an α=0.05 and a power of 80%, is 10 subjects (21). 
 
g. Dependent and independent variables 
Independent variable  
• 
Coffee consumption 
Dependent variables 
• 
Hunger 
• 
Satiety 
• 
Ghrelin concentrations 
• 
Cholecystokinin concentrations 
• 
Dietary intake the day of the intervention 
Confounding variables  
• 
Score on the "Food restriction" section of the Three Factor Eating Questionnaire. 
• 
Usual dietary Intake 
 
h. Biosafety considerations 
 
Biological-infectious waste (in this case blood) will be handled in accordance with Mexican Official 
Standard NOM-087-SEMARNAT-SSA1-2002, Environmental protection-health, environmental-
biological-infectious hazardous waste-classification, and handling specifications (22). The blood 
obtained from the patients will be contained in red and purple vacutainer tubes. These are 
centrifuged and the plasma and serum are separated and stored at -80ºC for later use. During all 
handling, personnel wear lab coats, laboratory glasses and gloves. All vacutainer tubes are 
discarded in an airtight red container that complies with the characteristics specified in the 
aforementioned standard. Sharps should be deposited in a rigid red polypropylene container with 
a lid, in accordance with the specifications of the same official Mexican standard (22). Once the 
containers are filled to 80% of their capacity, they are taken to the appropriate containers at the 
university where a company collects them for incineration. 
 
The laboratory techniques to be used include the determination of analytes in serum by dry 
chemistry, ELISA assays, and genomic DNA extraction (the latter for future use). The place where 
the techniques will be performed will be the INNUGET of the CUCS, which has a specific area to 
place the biological-infectious waste, showers, separate spaces for the different types of 
techniques, emergency telephones, evacuation route signs, and signs indicating the route for the 
transportation of the biological-infectious hazardous waste. Once the reagents have been used, 
they should be disposed of in an airtight red container that complies with the characteristics 
specified in NOM-087-SEMARNAT-SSA1-2002, and no reagents should ever be discharged into 
the sewage system (22).  
The research team Livier Nathaly Torres Castillo, Erika Martínez López, Citlalic Saraí Rodríguez 
Reyes and Wendy Yareni Campos Pérez have the knowledge to handle and minimize waste, as 
they have received training in this regard. In the event of any contingency, personal protective 
equipment will be worn, and precautionary signs will be followed. If a spill occurs, the surface will 

8 
 
be cleaned with powdered soap with felt and placed in a special red bag and/or in a bucket with 
water and sodium hypochlorite, applying chemical disinfectant or germicide (0.5% sodium 
hypochlorite), and then mopping using a mechanical squeeze bucket or latex gloves. Finally, the 
area should be sprayed with a chemical disinfectant or germicide and then mopped and dried. If 
containers with sharps fall into the area, the waste should be removed mechanically (tongs or a 
brush and dustpan), deposited in a special container (never with hands), the area should be 
sprayed with a chemical disinfectant or bactericide (0.5% sodium hypochlorite), cleaned and dried. 
Finally, the materials and utensils should be washed and disinfected. In the event of an accident, 
personal protective equipment must be removed and the area where the accident occurred must 
be washed and disinfected, and medical attention must be sought immediately, or emergency 
numbers called. 
 
i. Ethical considerations 
 
This protocol is adapted to the ethical principles of the regulations of the General Health Law on 
Health Research and is classified as "with greater than minimal risk", according to article 17 of 
this Law, since a method of assignment to therapeutic schemes is used (23). In addition, the well-
being, integrity, dignity, and rights of the participants will be respected in accordance with the 
Declaration of Helsinki (24). The standards of Good Clinical Practice (GCP), issued by the 
International Conference on Harmonization (GCP-ICH), are also considered, which protect and 
guarantee the rights, safety and well-being of the subjects participating in this research (25). 
 
In accordance with the General Health Law on Health Research, each participant will be given a 
copy of the corresponding informed consent form (Annex 1) and another copy will be kept by the 
principal investigator. The informed consent will explain in detail the characteristics of the study, 
its objectives, the methodology for the collection of information, benefits and consequences of 
their participation (23) and the confidentiality and dissociation of the data they provide us with and 
those obtained through the analysis of the blood sample; the latter in accordance with articles 18, 
19 and 21 of the Federal Law of Transparency and Access to Public and Governmental 
Information (26), and in accordance with the Mexican Official Standard 024-SSA3-2012, 
Electronic Registry Information Systems for Health. Health Information Exchange (27). 
 
The international ethical guidelines for health-related research in humans developed by the 
Council for International Organizations of Medical Sciences, are also considered: randomization 
will be performed to apply the study beverage or the control beverage to avoid bias and ensure 
that the study results reflect the effects of coffee according to guideline 5 "Choice of control 
mechanism for clinical trials", the control beverage (bottled water) is considered as minimal risk, 
it is a single intake and does not cause any harm to health, ensuring the protection of the 
participant's health and well-being. According to guideline 12 "Collection, storage and use of data 
in health-related research", the confidentiality and protection of the data is guaranteed, these data 
will only be used for scientific purposes, the participant's name will be replaced by a folio assigned 
to keep it anonymous, all this will be informed to the participant by means of an informed consent. 
Participants will be duly compensated for the time invested as mentioned in guideline number 13 
"Reimbursement and compensation for research participants". Our research group includes 

9 
 
women of childbearing age, not pregnant or lactating and without chronic diseases, their autonomy 
and low risk are guaranteed by receiving breakfast and test drinks according to guideline 18 
"Women as research participants" (28). 
 
The identification data of the participants will not appear in the databases, reports and publications 
derived from the project, only the identification number randomly assigned during the study to 
maintain and guarantee their anonymity. To guarantee the confidentiality and protection of the 
participants' personal data, this information is obtained in a format without identification folio and 
the clinical history format, the tubes for blood collection and processing, the format for body 
composition measurements, the visual analogue scales and all the questionnaires applied will 
contain only a randomly assigned folio and will not contain any personal data that could be used 
to identify the participant, whether it be by date of participation, address, name, etc. The 
information obtained will be kept and used for research purposes and only the research team will 
have access to it. In addition, each member of the research team will undertake not to disclose 
the data obtained by signing a letter of confidentiality. 
 
The benefits for the participants will be a feedback of their body composition, results of their 
glucose levels and lipid profile and individualized recommendations regarding their dietary intake, 
at no cost to them. In addition, an economic aid ($200.00 two hundred Mexican pesos) will be 
given for transportation so that participants can cover their travel expenses to INNUGET on the 
days of the three sessions and reduce their exposure to public transportation and thus avoid a 
COVID-19 infection. This benefit will be provided in cash and is specified in the informed consent 
form. The data obtained will contribute socially to create evidence and information on the effects 
that coffee consumption has on hunger, satiety, and hormones involved in the control of these 
processes in women with overweight or obesity. 
 
Storage of blood samples and clinical and nutritional information for future research 
projects 
 
It should be noted that the serum, plasma, and DNA obtained from the blood collection will be 
stored for further research at the INNUGET of the Centro Universitario de Ciencias de la Salud at 
a temperature of -80°C, for a maximum period of 8 years or less in the case of the amount of 
sample were very small. The samples will be used for subsequent biochemical tests, 
immunoassays, and DNA analysis. The information obtained will be used for further studies in 
order to learn more about the relationship between these serum and genetic parameters along 
with the diet intake, with the objective of expanding knowledge in the area of Nutrigenetics in the 
Mexican population. This is mentioned to the participants in the informed consent (Annex 1) as 
indicated in article 12 of the World Medical Assembly (WMA) declaration on the ethical 
considerations of health databases and biobanks (29). The databases are stored in a computer 
owned by the Universidad de Guadalajara to which only the principal investigator has access to 
such information. Access to the databases and samples by other researchers and/or students will 
only be allowed with the prior authorization of the principal investigator of this project and once a 
confidentiality letter has been signed, reiterating that the identification data of each participant will 
be dissociated, and it will not be possible to identify who they belong to. Any of the participants 

10 
 
may request a copy of the results obtained from their biological samples and these will be delivered 
by the principal investigator in a sealed envelope. If the information or biological sample cannot 
be identified, the person will not be able to know what is done with their information or biological 
sample, nor will they be able to withdraw their consent. 
Finally, the protocol was reviewed, approved, and registered by the Research, Research Ethics 
and Biosafety Committees of the CUCS of the Universidad de Guadalajara. 
 
9. Methodology (procedures) 
Selection of participants 
Adult women between 25 and 40 years of age will be invited to participate in this study through 
social networks and personal invitations. Participants who meet the inclusion criteria and agree to 
participate will sign the informed consent form. Their participation involves their attendance to 3 
sessions with a difference of one week between one and another. In the first session, they will be 
evaluated to determine whether or not they meet the inclusion criteria and will then be randomly 
assigned to the two types of interventions in the two subsequent sessions. 
 
Anthropometry and blood pressure  
Weight 
Weight measurement is performed in the morning, after a period of 8 to 12 hours of fasting, with 
light clothing and with bare feet. An InBody model 370 electrical bioimpedance device with an 
accuracy of 0.1 kg is used. The subject is placed in the center of the scale without support and 
with his/her weight equally distributed on both feet. 
 
Size 
The size measurement is made with a Seca stadiometer which has an accuracy of 0.1 cm. The 
subject stands with feet together (heels together and toes slightly apart). The heels, buttocks, 
upper back, and occipital are in contact with the stadiometer. The head is placed in the Frankfort 
plane, without touching the equipment. The subject is instructed to take a deep, sustained breath 
in. To make the measurement, the square is placed firmly on the highest point of the skull, 
compressing the hair as much as possible. The measurement is taken at the end of a deep breath. 
 
Waist circumference 
Waist circumference measurement is performed with a Lufkin anthropometric tape, which has an 
accuracy of 1 mm. The subject keeps the arms crossed on the thorax, heels together with the toes 
a little apart and the view in the Frankfort plane. The measurement is taken at the narrowest level, 
between the edge of the lower costal (tenth rib) and the iliac crest. The subject breathes normally, 
and the measurement is taken at the end of an exhalation. 
 
Hip circumference 
Hip circumference measurement is performed with the same Lufkin brand tape and in the same 
position as described for waist circumference. The circumference is taken at the maximum 
posterior level of the buttock bulge. 
 
Electrical bioimpedance  

11 
 
The measurements of fat mass, fat percentage, fat-free mass and bone mass are obtained 
through the InBody 370 equipment, under the same conditions described for the measurement of 
body weight. 
 
 
Blood Pressure 
Blood pressure measurement is performed in the morning, after 10 minutes of rest, with a 
LifeSource digital sphygmomanometer, the patient should be relaxed, seated, not stretched, with 
the back well supported by the back of the chair. The legs should be touching the floor, not 
crossed, and the hand relaxed, not clenched and in a resting position. The measurement is made 
on the reference or dominant arm resting at about the level of the heart. The subject's clothing 
does not cover the arm or fit snugly to the arm 25. 
 
Biochemical determinations  
 
Blood sampling 
In the second and third sessions a blood sample is taken in the morning, after a period of 8 to 12 
hours of fasting by venous puncture at times t=-30 min, t=0 min and t=180 min. Two vacutainer 
tubes, one red and one purple with 5 ml of blood, are obtained and centrifuged at 3500 rpm for 15 
minutes at 4° C to obtain serum and plasma for biochemical tests. 
Glucose and lipid profile determinations  
The determinations are performed in a Vitros 350 Chemistry equipment by dry chemistry. A 10 μl 
biological sample (serum) is applied to a slide containing the reagents that allow the detection of 
the analyte. 
 
LDL cholesterol is calculated with Friedewald's formula (30): 
LDL cholesterol= total cholesterol - HDL cholesterol - triglycerides/5. 
 
And VLDL cholesterol is also calculated with Friedewald's formula (30) as: 
Total cholesterol= (LDL cholesterol + HDL cholesterol). 
 
 
 

12 
 
Ghrelin 
Serum is obtained from the participants, from the same blood samples used to determine glucose 
and lipid profile. Ghrelin levels are determined using a RayBiotech kit, catalog number ELH-GHRL, 
and the plate is read on a Thermo Scientific Multiskan Sky spectrophotometer. The ghrelin assay 
is a sandwich ELISA assay using two specific, high-affinity antibodies. 
 
Cholecystokinin  
Serum is obtained from the participants, from the same blood samples. Cholecystokinin levels are 
determined using a RayBiotech kit, catalog number EIA-CCK-1, where the plate is read on a 
Thermo Scientific Multiskan Sky spectrophotometer. The cholecystokinin assay is a sandwich 
ELISA assay using two specific, high-affinity antibodies. 
 
Dietary evaluation 
Dietary Record  
In the first session, participants will receive instructions on how to fill out the dietary record format 
to evaluate the individuals' diet, they are asked to record all food and beverages consumed during 
a 3-day period, being a weekday, a weekend day and the day prior to their second session. 
Nutritionist ProTM Diet Analysis software (Axxya Systems, Stafford, TX, USA) is used for diet 
analysis. 
 
Frequency of consumption of foods with caffeine 
A search of the nutritional information of foods and beverages with coffee and/or caffeine most 
consumed in Mexico was made in the food databases, the magazine “Revista del Consumidor”, a 
publication of the Mexican government, and in other sources where that information was available. 
This information was used to design a coffee and caffeine products frequency products and will 
be applied in each of the sessions to the participants. 
 
Questionnaires  
Clinical history  
A clinical history will be taken during the first session to obtain information on pathological history, 
clinical data, nutritional aspects, sociodemographic and lifestyle aspects. 
 
Visual analog scales  
This evaluation format, which was previously reproduced and adapted to Spanish by our research 
group (manuscript in preparation), consists of questions that are asked before and after 
consuming breakfast, and subsequently at certain time intervals. The visual analog scales are 
composed of lines, usually 100 mm long, on which at one end is placed the term "None" or "Not 
at all" and at the other end the term "Yes, a lot" or "As much as I have never felt". The patient 
marks a point between these two extremes and quantification is done by measuring the distance 
from the left end of the line to the mark to which a score is given (31).  
 
Physical Activity Questionnaire (IPAQ) short version 
This instrument is a physical activity assessment format, that examines different dimensions of 
patient physical activity, such as time spent in walking, moderate and vigorous intensity activities 

13 
 
and time spending in sedentary activities. Weekly physical activity is measured by recording in 
METs (metabolic equivalent of task) per min per week. After calculating the physical activity index, 
whose value corresponds to the product of the intensity (in METs) times the frequency times the 
duration of the activity. The subjects are classified into 3 categories of high, moderate, and low 
physical activity (32). This questionnaire will be applied in the second and third sessions. 
 
Three-factor eating questionnaire 
This questionnaire consists of 51 items and is applied in the first session to assesses three 
dimensions of eating behavior: a) dietary restraint, consisting of 21 items intended to measure the 
cognitive dominance of food intake; b) disinhibition, containing 16 items assessing the tendency 
to overeat and loss of control overeating; and c) hunger susceptibility, with 14 items estimating 
subjective feelings of hunger and desire for food (33,34). 
 
Breakfast 
Participants will receive 2 breakfasts in two different sessions; one of them will consist of a 
breakfast that will include simple water as a beverage and in another session, they will have the 
same breakfast, but the beverage to be consumed will be coffee. The order in which the two types 
of beverages will be consumed will be random. Each breakfast will be offered 1 week apart and 
will consist of the following: 
 
▪ 
Breakfast with coffee 
1 cup of coffee with 6 mg/kg of body weight of caffeine and a breakfast with 400 kcal, with a 
distribution of 50% carbohydrates, 30% lipids and 20% protein. 
 
A Veracruz coffee will be used, which according to a study carried out by the Federal Consumer 
Protection Agency (Profeco) reports that for every 7 grams of this coffee there are 111 mg of 
caffeine (35); once the participant's weight is obtained, a calculation will be made to know the 
amount in grams of coffee to be used; finally, the amount of coffee in 250 ml of water will be 
prepared. Likewise, before the intervention, tests will be carried out to see the tolerance to the 
taste. 
 
▪ 
Breakfast without coffee 
1 cup of simple water and a breakfast with 400 kcal, with a distribution of 50% carbohydrates, 
30% lipids and 20% protein. 
 
In the research carried out by Gavrieli et al. (3,4) and in a study by Beaudoin M et al. (36), simple 
water was used as a control beverage to analyze the effect of coffee on appetite regulating 
hormones. Based on this, it was decided to use simple swater as the control beverage for this 
study to make comparisons with the results obtained in other investigations.    
 
Statistical analysis  
For descriptive statistics, quantitative variables will be expressed as mean ± standard deviation or 
median and interquartile range, and qualitative variables as frequency or percentage. For 
inferential statistics, the distribution of the variables will first be analyzed with the Shapiro-Wilk 
test. In the event that the variable is not normally distributed, a logarithmic transformation will be 

14 
 
made, and it will be checked again if it is normally distributed; in the event that the variable 
continues with a non-normal distribution, non-parametric statistical tests will be used. 
For comparisons between the two treatments, the mixed general linear model will be used. The 
data will be entered into an Excel spreadsheet to later be imported into the SPSS v.21 program 
for analysis, considering a value of p<0.05 as statistically significant. The graphs will be made with 
the Gradhpad software version 9.3.1. 
 
10. Project viability 
 
a. Funding 
Financial resources are available to cover the expenses necessary to carry out the project, through 
the program "Support for the Incorporation of NPTC", report number 511-6/2020-8586 and through 
the PRO-SNI 2021 fund.  
 
b. Infrastructure 
Access to INNUGET of the University Center of Health Sciences of the Universidad de 
Guadalajara is available, which has all the necessary equipment to carry out this project. 
 
11. References 
 
1.  
Schubert MM, Irwin C, Seay RF, Clarke HE, Allegro D, Desbrow B. Caffeine, coffee, and 
appetite control: a review. Int J Food Sci Nutr. 2017 Dec;68(8):901–12.  
2.  
Greenberg JA, Geliebter A. Coffee, hunger, and peptide YY. J Am Coll Nutr. 2012 
Jun;31(3):160–6.  
3.  
Gavrieli A, Karfopoulou E, Kardatou E, Spyreli E, Fragopoulou E, Mantzoros CS, et al. 
Effect of different amounts of coffee on dietary intake and appetite of normal-weight and 
overweight/obese individuals. Obes Silver Spring Md. 2013 Jun;21(6):1127–32.  
4.  
Gavrieli A, Yannakoulia M, Fragopoulou E, Margaritopoulos D, Chamberland JP, Kaisari P, 
et al. Caffeinated coffee does not acutely affect energy intake, appetite, or inflammation but 
prevents serum cortisol concentrations from falling in healthy men. J Nutr. 2011 Apr 
1;141(4):703–7.  
5.  
Watanabe T, Kobayashi S, Yamaguchi T, Hibi M, Fukuhara I, Osaki N. Coffee Abundant in 
Chlorogenic Acids Reduces Abdominal Fat in Overweight Adults: A Randomized, Double-
Blind, Controlled Trial. Nutrients. 2019 Jul 16;11(7).  
6.  
Schubert MM, Grant G, Horner K, King N, Leveritt M, Sabapathy S, et al. Coffee for 
morning hunger pangs. An examination of coffee and caffeine on appetite, gastric 
emptying, and energy intake. Appetite. 2014 Dec;83:317–26.  
7.  
Campos-Vega R, Arreguín-Campos A, Cruz-Medrano MA, Del Castillo Bilbao MD. Spent 
coffee (Coffea arabica L.) grounds promote satiety and attenuate energy intake: A pilot 
study. J Food Biochem. 2020 Jun;44(6):e13204.  
8.  
Obesity and overweight [Internet]. [cited 2021 Apr 23]. Available from: 
https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight 

15 
 
9.  
Williams EP, Mesidor M, Winters K, Dubbert PM, Wyatt SB. Overweight and Obesity: 
Prevalence, Consequences, and Causes of a Growing Public Health Problem. Curr Obes 
Rep. 2015 Sep;4(3):363–70.  
10.  IMCO — Kilos de más, pesos de menos: Los costos de la obesidad en México [Internet]. 
IMCO — Kilos de más, pesos de menos: Los costos de la obesidad en México. [cited 2021 
Apr 23]. Available from: https://imco.org.mx/kilos-de-mas-pesos-de-menos-obesidad-en-
mexico/ 
11.  Koliaki C, Liatis S, Dalamaga M, Kokkinos A. The Implication of Gut Hormones in the 
Regulation of Energy Homeostasis and Their Role in the Pathophysiology of Obesity. Curr 
Obes Rep. 2020 Sep;9(3):255–71.  
12.  Haidari F, Samadi M, Mohammadshahi M, Jalali MT, Engali KA. Energy restriction 
combined with green coffee bean extract affects serum adipocytokines and the body 
composition in obese women. Asia Pac J Clin Nutr. 2017;26(6):1048–54.  
13.  Roshan H, Nikpayam O, Sedaghat M, Sohrab G. Effects of green coffee extract 
supplementation on anthropometric indices, glycaemic control, blood pressure, lipid profile, 
insulin resistance and appetite in patients with the metabolic syndrome: a randomised 
clinical trial. Br J Nutr. 2018;119(3):250–8.  
14.  Makovey J, Naganathan V, Seibel M, Sambrook P. Gender differences in plasma ghrelin 
and its relations to body composition and bone - an opposite-sex twin study. Clin 
Endocrinol (Oxf). 2007 Apr;66(4):530–7.  
15.  Bakuradze T, Parra GAM, Riedel A, Somoza V, Lang R, Dieminger N, et al. Four-week 
coffee consumption affects energy intake, satiety regulation, body fat, and protects DNA 
integrity. Food Res Int. 2014 Sep 1;63:420–7.  
16.  Douglas BR, Jansen JB, Tham RT, Lamers CB. Coffee stimulation of cholecystokinin 
release and gallbladder contraction in humans. Am J Clin Nutr. 1990 Sep;52(3):553–6.  
17.  International Coffee Organization - Trade Statistics Tables [Internet]. [cited 2021 Apr 23]. 
Available from: https://www.ico.org/trade_statistics.asp?section=Statistics 
18.  Consumidor PF del. Despierta y conoce + sobre el café [Internet]. gob.mx. [cited 2021 Apr 
23]. Available from: http://www.gob.mx/profeco/documentos/despierta-y-conoce-sobre-el-
cafe 
19.  Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 
1698 population-based measurement studies with 19·2 million participants. The Lancet. 
2016 Apr 2;387(10026):1377–96.  
20.  Encuesta Nacional de Salud y Nutrición - MC [Internet]. ENSANUT. [cited 2020 Feb 25]. 
Available from: https://ensanut.insp.mx/encuestas/ensanut2016/index.php 
21.  Horner KM, Byrne NM, King NA. Reproducibility of subjective appetite ratings and ad 
libitum test meal energy intake in overweight and obese males. Appetite. 2014 Oct;81:116–
22.  

16 
 
22.  NOM-087-SEMARNAT-SSA1-2002 Protección ambiental-salud, ambiental-residuos 
peligrosos biológico-infecciosos-clasificación y especificaciones de manejo. | Comisión 
Nacional de los Derechos Humanos - México [Internet]. [cited 2021 Apr 24]. Available from: 
https://www.cndh.org.mx/documento/nom-087-semarnat-ssa1-2002-proteccion-ambiental-
salud-ambiental-residuos-peligrosos 
23.  Reglamento de la Ley General de Salud en Materia de Investigación para la Salud 
[Internet]. [cited 2019 Sep 5]. Available from: 
http://www.salud.gob.mx/unidades/cdi/nom/compi/rlgsmis.html 
24.  World Medical Association. World Medical Association Declaration of Helsinki: ethical 
principles for medical research involving human subjects. JAMA. 2013 Nov 
27;310(20):2191–4.  
25.  Osorio L. What everybody should know about good clinical practices. Biomédica. 2015 Jun 
1;35(2):274–84.  
26.  Social IN de D. Ley Federal de Transparencia y Acceso a la Información Pública (Marco 
Normativo) [Internet]. gob.mx. [cited 2021 Apr 25]. Available from: 
http://www.gob.mx/indesol/documentos/ley-federal-de-transparencia-y-acceso-a-la-
informacion-publica-marco-normativo 
27.  DOF - Diario Oficial de la Federación [Internet]. [cited 2021 Apr 25]. Available from: 
http://dof.gob.mx/nota_detalle.php?codigo=5280847&fecha=30/11/2012 
28.  World Health Organization, Council for International Organizations of Medical Sciences. 
International ethical guidelines for health-related research involving humans. Geneva: 
CIOMS; 2017.  
29.  WMA - The World Medical Association-WMA Declaration of Taipei on Ethical 
Considerations regarding Health Databases and Biobanks [Internet]. [cited 2021 Jun 11]. 
Available from: https://www.wma.net/policies-post/wma-declaration-of-taipei-on-ethical-
considerations-regarding-health-databases-and-biobanks/ 
30.  Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density 
lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 
1972 Jun;18(6):499–502.  
31.  Flint A, Raben A, Blundell JE, Astrup A. Reproducibility, power and validity of visual 
analogue scales in assessment of appetite sensations in single test meal studies. Int J 
Obes Relat Metab Disord J Int Assoc Study Obes. 2000 Jan;24(1):38–48.  
32.  Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, et al. 
International physical activity questionnaire: 12-country reliability and validity. Med Sci 
Sports Exerc. 2003 Aug;35(8):1381–95.  
33.  Stunkard AJ, Messick S. The three-factor eating questionnaire to measure dietary restraint, 
disinhibition and hunger. J Psychosom Res. 1985;29(1):71–83.  
34.  Sánchez Carracedo D, Raich RM, Figueras Piqueras M, Torras Clarasó J, Mora Giral M. 
Adaptación preliminar del cuestionario de alimentación de Stunkard y Messick (Three 

17 
 
Factor Eating Questionnaire, TFEQ) con una muestra española universitaria. Psicol 
Conduct Behav Psychol. 1999;7(3):0393–416.  
35.  9607743. Revista del Consumidor noviembre 2018 [Internet]. Issuu. [cited 2021 Jun 27]. 
Available from: https://issuu.com/profeco/docs/revista_del_consumidor_noviembre_20 
36.  Beaudoin M-S, Robinson LE, Graham TE. An oral lipid challenge and acute intake of 
caffeinated coffee additively decrease glucose tolerance in healthy men. J Nutr. 2011 Apr 
1;141(4):574–81.  
 
 

18 
 
  
ANNEX 1 
 
INFORMED CONSENT TO PARTICIPATE IN THE STUDY ENTITLED: 
 
 
 
Effect of coffee consumption on hunger, satiety, appetite-regulating hormones, and diet 
intake in women with overweight or obesity 
 
Project managers 
Dra. en C. Livier Nathaly Torres Castillo y Dra. en C. Saraí Citlalic Rodríguez Reyes 
Study location: 
Centro Universitario de Ciencias de la Salud de la Universidad de Guadalajara 
Date (dd/mm/yyyy): _____ / _____ / ________ 
Participant's name: __________________________________________________ 
 
You are being invited to participate in this research study. Before you decide whether or not to participate, 
you should know and understand each of the following sections. This process is known as informed consent. 
Feel free to ask questions about anything that will help clarify your concerns. 
Once you have understood the study and if you wish to participate, then you will be asked to sign this 
consent form. A signed and dated copy of which will be given to you. 
 
PATIENT INFORMATION 
 
JUSTIFICATION FOR THE STUDY 
In Mexico, according to the latest National Health and Nutrition Mid-Track Survey (ENSANUT-MC,2018) 
75% of the adult Mexican population is overweight. In the case of premenopausal women, the prevalence 
of obesity in the age range of 30 to 49 years was 89%. Jalisco also had an increase in the prevalence of 
obesity from 37.6% in 2012 to 39.8% in 2018. Preventing and treating obesity early, as well as seeking and 
finding complements that suit the patient to execute more effective nutritional interventions, has benefits for 
the individual patient and for the healthcare system in general. In the search for supplements to implement 
effective nutritional interventions to combat this problem, we find coffee. Recently, this beverage has caused 
great interest since recent findings suggest that coffee has an effect on appetite control which could help in 
weight control. For this reason, this study will be important to contribute to the knowledge gap that exists 
regarding the effects of coffee on hunger, satiety, appetite regulating hormones and diet intake in women 
with overweight or obesity. 
 
OBJECTIVE OF THE STUDY 
You are being invited to participate in this research project which aims to learn about the effects of coffee 
on hunger, satiety, appetite regulating hormones, and diet intake in women with overweight or obesity. 
 
STUDY PROCEDURE 
If you decide to participate, you will be scheduled on three different occasions. In session 1 a nutritionist will 
evaluate your weight, height, waist circumference, percentage of fat, percentage of body water and amount 
of muscle, the last three will be done in an electrical bioimpedance equipment, which is similar to a scale 
and to get on this equipment you will have to do it with bare feet (this will not cause you any discomfort or 

19 
 
pain). You will also be asked a series of questions to fill out a medical history, similar to when you attend a 
consultation with a doctor, and you will be asked a questionnaire on eating behavior. In this first session 
you will be instructed to record your food and beverage intake for 2 days. 
You will be scheduled for a second session corresponding to day 1 or 2 of the start of your menstrual cycle. 
At this second session you will need to attend with a fasting period of at least 8 hours. First a blood sample 
will be taken, then you will be given a breakfast (which may include simple water or coffee) and at 30 to 180 
minutes after finishing your breakfast, your blood sample will be taken again. In addition, on an empty 
stomach, after consuming your breakfast and at 30, 60, 90, 120, 150 and 180 minutes you will answer 
questions to assess your hunger and satiety. One week later you will be scheduled for the third session 
where we will perform the same procedure as in session 2, with the only difference that, if in session 2 you 
received your breakfast with coffee, this third time you will be given the same breakfast, but with simple 
water or vice versa. 
 
-About the storage of samples and clinical and nutritional information for future research projects 
Your participation in this study also includes storing your DNA, blood serum and plasma for further research. 
Your samples will be stored in a laboratory within the University Health Sciences Center at a temperature 
of -80 degrees for a maximum period of 8 years or less if the amount of sample is very small. Your samples 
will be used for further biochemical tests and immunoassays (measuring substances naturally found in the 
blood) and analysis of your DNA. The information obtained from your samples will be used for further studies 
to learn more about the relationship between these components in your blood, the diet and the DNA, which 
will allow for more accurate health and nutrition recommendations for the Mexican population in the future. 
The researchers and/or students who participate in this study will be able to access all the times to the 
samples and results obtained, and they could also be shared with other Mexican researchers and 
researches in other countries, but at all times your information and personal data will be protected by a 
code, so that your data and information will have a folio instead of your name or any other identifying 
information, in this way we guarantee absolute confidentiality, i.e. no one can know that the sample is yours. 
In addition, in order for the researchers to have access to the information obtained in this study, they will 
sign a confidentiality letter where they commit to maintain the privacy of your personal data. The databases 
are stored in a computer owned by the University of Guadalajara to which only the principal investigator has 
access and the information contained therein may be shared with other researchers or students with whom 
they collaborate as long as the confidentiality letter is signed. Access to the databases and samples by 
other researchers and/or students will only be allowed with the prior authorization of the principal investigator 
of this project and once the confidentiality letter has been signed, reiterating that the identification data of 
each participant will be separated, and it will not be possible to identify who they belong to. You may request 
a copy of the results obtained from your biological samples and these will be delivered by the principal 
investigator in a sealed envelope. In the case that the information or biological sample cannot be identified, 
you will not be able to know what is done with your information or biological sample, nor will you be able to 
withdraw your consent. 
It is worth mentioning that the information obtained here may be published in different scientific journals and 
scientific congresses in the future, but the confidentiality of your personal data will always be respected, as 
these will never be disclosed by any means. 
 
RISKS 
In accordance with the Regulations of the General Law of Health on Research for Health, this research is 
considered with a higher than minimal risk, because it is randomly assigned whether you will receive coffee 
or simple water in the first intervention.  
 
VOLUNTARY 

20 
 
Your participation in this study is completely voluntary, so at any time you can stop participating in this study 
without having to give explanations to the investigators. 
 
CONFIDENTIALITY  
All information generated and personal data will be treated confidentially. Your identification data will not 
appear in the databases since only a participant folio will be shown. In the final report of the study, in the 
publication of results in scientific congresses, in publications in scientific journals and at all times, your 
identity will be kept anonymous. To guarantee the confidentiality and protection of your personal data, all 
the forms and questionnaires, as well as the tubes where the blood sample will be taken, will only have a 
folio (a number) assigned randomly and no personal data that could be used to identify you, not even by 
your date of participation, address, etc., will appear on them. 
 
BENEFITS AND RESULTS 
At the end of the session, you will receive free feedback on the interpretation of your weight, height, fat 
percentage, amount of muscle and your body mass index classification. You will also receive nutritional 
recommendations based on your dietary assessment, telling you how to improve your eating habits. Finally, 
participants will be given a financial assistance ($200.00 two hundred pesos) for transportation to cover 
their travel expenses to CUCS on the days of the three sessions and to reduce their exposure to public 
transportation to avoid COVID-19 infection. 
 
DISCLAIMERS: 
• 
Your decision to participate in the study is completely voluntary. 
• 
There will be no unfavorable consequences for you if you do not accept the invitation. 
• 
You may withdraw your participation at any time, even if you have already signed this consent form 
without explanation. 
• 
You may request information obtained during the study, even if it might interfere with your decision 
to continue participating in the study. 
• 
You will not have to pay any expenses during the study 
 
CONTACT INFORMATION FOR CLARIFICATIONS OR DOUBTS 
If you have any questions, doubts, comments, or concerns regarding the project, please contact any of the 
researchers responsible for the project at the addresses below, where you are guaranteed to receive a 
response to whatever your concern may be. 
 
-Dra. en C. Livier Nathaly Torres Castillo (phone number 3310585200 ext. 34284) 
(nathaly.torrescas@academicos.udg.mx).  
-LN Lisset Magaña de la Vega (phone number 3318409211) (lissma14@gmail.com) 
 
 
 

21 
 
LETTER OF INFORMED CONSENT 
 
I, ________________________________________________________________, declare that I have 
read and understood the above information and my questions have been answered in simple language, in 
a sufficiently clear and satisfactory manner. I have been informed and understand that the data obtained in 
the study may be published or disseminated for scientific purposes without my name being disclosed. I also 
understand that at any time and without giving any explanation (if I prefer), I may revoke the consent I now 
give. I therefore agree to participate in this research study for the proposed purposes. And I will receive a 
signed and dated copy of this consent form. 
 
Guadalajara, Jalisco, _(day)__  of __(month)____ of _(year)__ 
 
 
 
 
 
Participant's name and signature 
 
 
Witness 1 
 
Witness 2 
 
 
 
 
 
 
 
 
 
Name and signature 
 
Name and signature 
 
 
 
 
 
 
 
 
 
Address 
 
Address 
 
 
 
 
 
 
 
 
 
Relationship with the investigator 
 
Relationship with the investigator 
 
 
This part must be completed by the investigator (or his/her representative): 
I, ________________________________________________________________, have explained to the 
participant the nature and purposes of the research; I have explained the objective of the study and the 
importance of their participation. I have answered questions to the best of my ability and have finally asked 
if there were any remaining doubts. I accept that I have read and know the corresponding regulations for 
conducting research with human subjects and that I, as well as my work group, adhere to them. Once the 
question-and-answer session was concluded, the present document was signed. 
 
 
 
 
 
 
Name and signature of researcher and/or 
representative 
 
Witness name and signature 
 
 
 
 
 
Relationship with the investigator and/or 
representative: