Meal Timing, Genetics and Weight Loss

Study Overview
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Brief Summary
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Meal times differ from culture to culture. These differences may influence energy regulation and, consequently, body weight. Current studies support the notion that not only what but also when the investigators eat may have a significant role in obesity treatment. Recently, it has been shown that eating the main meal of the day, lunch in Spain, late in the day is predictive of difficulty in weight loss and decreased insulin sensitivity. This project aims to study in a Mediterranean population the potential influence of genetics and food timing on obesity, metabolic syndrome and weight loss.

Detailed Description
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Meal times differ from culture to culture. These differences may influence energy regulation and, consequently, body weight. Current studies support the notion that not only what but also when the investigators eat may have a significant role in obesity treatment. Recently, it has been shown that eating the main meal of the day, lunch in Spain, late in the day is predictive of difficulty in weight loss and decreased insulin sensitivity. Furthermore, it has been shown that eating late at night when plasma melatonin concentrations are elevated, impairs glucose tolerance, particularly in MTNR1B risk allele carriers. The main objective is to identify the mechanisms underlying the association between the timing of food intake, obesity and metabolic syndrome (MetS) in order to design effective weight loss therapies. The long-term goal is to determine the potential impact of more European, i.e., earlier meal timing on obesity, MetS and weight loss. The challenge for the society is to develop evidence-based dietary interventions incorporating meal timing and genotype to combat the epidemic of obesity and MetS. These goals will be achieved through three specific approaches: Epidemiological (observational study) (Aim 1): To assess in an obese population (n=5000) who will follow a weight loss program if clock-related (CLOCK, PER2, CRY, etc.) and melatonin-related variants (MTNR1B) interact with the timing of food intake to determine weight loss effectiveness and MetS features. Interventional (randomized controlled trials) (Aim 2): To determine the internal mechanisms of energy balance and circadian system implicated in the differential effects of food timing (lunch) on weight loss, MetS alterations and the intestinal microbiota (n=25), and to study the potential interaction between meal timing (dinner) and genetic variants MTNR1B for glucose tolerance in obese women (n=100).

Official Title
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Meal Timing, Genetics and Weight Loss in a Mediterranean Population

Conditions
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Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body Mass Index: >25 kg/m2 Age: >18 years of age Caucasian Exclusion Criteria: Receiving treatment with thermogenic, lipogenic, or contraceptive drugs Diabetes mellitus, chronic renal failure, hepatic diseases, or cancer diagnosis bulimia diagnosis, prone to binge eating undergoing treatment with anxiolytic or antidepressant drugs

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total weight loss | Body weight will be measured in barefoot wearing light clothes, with a digital scale to the nearest 0.1 kg, at the same time each day. | weekly, during the 28 weeks of treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Food timing | Timing of breakfast, lunch and dinner | at baseline | 
| Sleep timing | Habitual sleep timing is estimated using a self-reported questionnaire. | at baseline | 
| Siesta timing questionnaire | Habitual siesta timing is estimated using a self-reported questionnaire. | at baseline | 
| Individual chronotype questionnaire | With the Morning and Eveningness Questionnaire (MEQ) | at baseline | 
| Food habits questionnaire | Variety of food groups is assessed by at 24h recall the day before starting the intervention and by a a seven days dietary record during the intervention. The number of different food items per day will be counted to assess variety of food | at baseline | 
| Total energy intake dietary questionnaire | by at 24h recall the day before starting the intervention and by a a seven days dietary record during the intervention. Daily energy intake will be calculated | at baseline | 
| Macronutrient distribution dietary questionnaire | by at 24h recall the day before starting the intervention and by a a seven days dietary record during the intervention. Macronutrient (% from total calories of the diet) and (grams) will be calculated | at baseline | 
| Glycemic Index questionnaire | by at 24h recall the day before starting the intervention and by a a seven days dietary record during the intervention. The glycemic index will be calculated by using different composition tables | at baseline | 
| Barriers to Weight Loss checklist | A questionnaire will be complete by the participants. The test consisted of 29 questions classified into seven sections: meal recording; weight control and weekly interviews; eating habits; portion size; food and drink choice; way of eating; and other obstacles to weight loss. There are were three possible responses (never 0, sometimes 1, very often 2) to those questions that represented barriers to losing weight, such as ''Have you lost your motivation?'' or ''Do you have binges?'' Questions that represented aids to weight loss, such as ''Do you accurately measure your portions?'' or ''Is absolutely everything written down?'' applied the same score (0 to 2) but with negative signs. A final ''Barriers to Weight Loss'' score is calculated by adding every answer's score for each patient. | at baseline | 
| Emotional eating questionnaire | The EEQ (Emotional eating Questionnaire) will be used extent emotions affect eating behaviour. . All the questions had four possible replies: 1) Never, 2) Sometimes; 3) Generally and 4) Always. Each reply was given a score of 1 to 4, the lower the score, the healthier the behaviour. For the clinical practice subjects are classified in four groups attending to the score obtained. Score between 0-5: non-emotional eater. Score between 6-10: low emotional eater. Score between 11-20: emotional eater. Score between 21-30: very emotional eater. | at baseline | 
| Physical activity questionnaire | by the IPAQ (international Physical Activity Questionnaire) | at baseline | 
| Mediterranean Diet Score questionnaire | By the questionnaire developed by Antonia Trichopoulou, M.D., Tina Costacou, Ph.D., Christina Bamia, Ph.D., and Dimitrios Trichopoulos, M.D. N Engl J Med 2003; 348:2599-2608June 26, 2003DOI: 10.1056/NEJMoa025039 | at baseline | 
| Glucose tolerance | either by meal test or by glucose tolerance test | from 1 year to 3 years after weight loss treatment | 
| Daily rhythms of wrist temperature | 7 day-record of wrist temperature by wrist temperature sensors. | from 3 months to 3 years after weight loss treatment | 
| Daily rhythms of activity | 7 day-record of activity by actiwatch | from 3 months to 3 years after weight loss treatment | 
| Daily rhythms of autonomus system by ambulatory electrocardiography | 7 days of ambulatory electrocardiography | from 3 months to 3 years after weight loss treatment | 
| Glucose | Fasting glucose | at baseline | 
| Insulin | Fasting insulin | at baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Nutrigenetics, Food Timing, Weight loss