Clinical trial NCT05627570: A Study Comparing the Health Effects of Two Diets Following UK Dietary Guidance in People Living with Overweight or Obesity
Official title: Investigating the Effects of Diets with Different Types of Food Processing Following UK DietAry Guidance on HealTh OutcomEs: an 8-week Community-based Crossover Randomised Controlled Trial in People with Overweight or Obesity, Followed by a 6-month Behavioural Intervention
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Obesity
Cardiometabolic Syndrome
Overweight
Keywords: Food processing
Diet
Healthy, balanced diet
Dietary guidelines
Obesity
Cardiometabolic disease
Lead sponsor: University College, London
Sponsor class: OTHER
Collaborators: name: University College London Hospitals
First posted: 2022-11-25
Enrollment: 55
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: 2x2, randomised, controlled crossover trial
Primary purpose: TREATMENT

Brief summary: There are two parts to this study:

1. The investigators will study if the benefit from eating a healthy, balanced diet depends on the types of food processing in the diet. The investigators will do this by providing participants with two diets that follow the Eatwell Guide (referred to in this study as Diet A and Diet B to avoid unblinding), but containing foods with different types of food processing, for 8 weeks each. The investigators will collect data on blood pressure, body composition, physical activity and fitness, questions regarding quality of life, mental health and wellbeing, and blood samples at the start of each diet and at 4 and 8 weeks into each diet.
2. The investigators will then study whether participants are able to switch from their usual unhealthy diet to a healthy, balanced diet, and the benefits of doing so. The investigators will do this by providing participants with 6 months of personal support. The investigators will also look at what helps participants to maintain a healthy diet, and what makes it difficult. The investigators will also support participants to be more physically active.

Detailed description: Eating a healthy, balanced diet is important for health. A healthy, balanced diet involves eating a variety of foods in the right proportions. In the UK, the Eatwell Guide gives recommendations on what people should eat more of, and what people should eat less of. Unhealthy diets contain lots of foods high in saturated fat, added sugar and salt, which increases the risk of developing obesity, cardiovascular disease and type 2 diabetes. Advice for a healthy, balanced diet includes consuming five portions of fruit and vegetables per day and eating more high fibre foods. Following the healthy, balanced diet advice given in the Eatwell Guide can reduce the risk of poor health.

However, there are other parts of the diet that are not covered in the Eatwell Guide that may also be important for health. For example, research suggests that different types of food processing might influence health, but these types of food processing are not included within the recommendations.

It is unknown if the benefits of following the healthy diet advice in the Eatwell Guide depend on the types of food processing in the diet. It is important to find out if these types of food processing matter, in order to give people the best advice possible. It also means that the government and other health organisations may need to change the regulations around the food that people eat.

To answer this, the investigators will compare the effects of two healthy, balanced diets following the advice in the UK Eatwell Guide, but each based on a different type of food processing (referred to in this study as Diet A and Diet B to avoid unblinding). Participants will receive the first diet for 8 weeks, return to their normal diet for 4 weeks, and then receive the second diet for a further 8 weeks. Participants will have 6 months of support to help improve their diet and be more physically active. Participants will work with a behavioural scientist to create a personal plan to eat a healthier diet and be more physically active, using behaviour change techniques based on capability, opportunity, motivation - behaviour (COM-B) theory of behaviour change. This support will last for 6 months, with ongoing monthly telephone/video calls with the research team. The results from this study will be used to help inform UK dietary guidance and food policy.

There are two parts to this study:

1. The investigators will study if the benefit from eating a healthy, balanced diet depends on the types of food processing in the diet. The investigators will do this by providing participants with two diets (Diet A and Diet B) that follow the Eatwell Guide, but containing foods with different types of processing, for 8 weeks each.
2. The investigators will then study whether participants are able to switch from their usual unhealthy diet to a healthy, balanced diet, and the benefits of doing so. The investigators will do this by providing participants with 6 months of personal support. The investigators will also look at what helps participants to maintain a healthy diet, and what makes it difficult. The investigators will also support participants to be more physically active.

Eligibility criteria: Inclusion Criteria:

* Staff at University College London Hospitals (UCLH)
* Adults aged between \[18 and 65\] years old.
* BMI ≥25 kg/m2 (living with overweight or obesity)
* Weight stable for the past 3 months (≤5 % variation in body weight over preceding 3 months)
* Have a habitual dietary intake high in unhealthy food
* Able to read and write in English.
* Medically safe to participate in a dietary intervention programme.
* Willing and able to give written informed consent.
* Able to attend the relevant in person and online sessions.
* Able to comply with the study protocol (including dietary recommendations for each intervention and reporting adherence).
* Females of childbearing potential and males agree to use an effective method of contraception from the time consent is signed until the end of the intervention period and final follow-up assessment. Effective methods of contraception acceptable for this trial are outlined in Appendix 2.
* Females of childbearing potential must be on highly effective contraception and have a negative pregnancy test within 7 days of being randomised. NOTE: Participants are considered not of childbearing potential if they have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or they are postmenopausal.

Exclusion Criteria:

* Contraindication for dietary intervention
* Participation in another clinical intervention trial
* Concomitant usage of medications that cause weight gain or weight loss
* Cardiometabolic comorbidities (e.g. diabetes, on insulin)
* Coeliac disease
* Inflammatory bowel disease
* A diagnosed eating disorder
* Planning a weight management programme in the next 3 months
* Any diagnosed food allergy, or other allergies which limit the ability to adhere to the intervention diet
* Dietary restrictions (e.g. vegan or vegetarian) which limit the ability to adhere to the interventions
* BMI \>40 kg/m2 or basal metabolic rate ≥2300/kcal/day (to ensure intervention diets are at least 300kcal/day greater than maintenance energy needs).
* Females who are pregnant, breast-feeding, or intends to become pregnant.
* A history of drug or alcohol abuse
* Any other factor making the participant unsuitable in the view of investigator.

Primary outcomes:
measure: Mean difference in percent weight change (%WC) at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
Secondary outcomes:
measure: Changes in waist circumference at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in waist circumference after 6-months of the behavioural support programme
timeFrame: First baseline to 6-months follow-up
measure: Changes in fat-free mass at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in fat-free mass after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in fat mass at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in fat mass after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in heart rate at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in heart rate after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in systolic and diastolic blood pressure at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in systolic and diastolic blood pressure after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in comorbidities at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in Liver function at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in Glucose at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in Lipids at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in HbA1c at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in C-reactive protein (CRP) at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in metabolomics at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in Comorbidities after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in Liver function after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in Glucose after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in metabolomics after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in Lipids after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in HbA1c after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in C-reactive protein (CRP) after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in appetite at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in gut hormones at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in adipocytokines at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in appetite after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in gut hormones after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in adipocytokines after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in sleep at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in sleep quality at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in sleep after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in sleep quality after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in physical activity at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in physical activity levels at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in physical activity after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in physical activity levels after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in handgrip strength at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in handgrip strength after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in walking distance at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in changes in walking distance after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in leg strength at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in leg strength after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in quality of life at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in quality of life after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in weight-related quality of life at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in weight-related quality of life after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in mental wellbeing at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in mental wellbeing after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in depression at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in depression after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in anxiety at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in anxiety after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in eating behaviour (psychological impact of living in food-abundant environments) at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in eating behaviour (psychological impact of living in food-abundant environments), after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: Changes in eating behaviour (severity and type of food cravings) at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in eating behaviour (severity and type of food cravings), after 6-months of the behavioural support
timeFrame: First baseline to 6-months follow-up
measure: (In a subset of participants) Changes in brain functional resting state connectivity at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: (In a subset of participants) Changes in brain functional resting state metabolism at 8 weeks between Diet A and Diet B
timeFrame: Baseline to 8 weeks for both diets
measure: Changes in aspects of behaviour regulation after 6-months of the behavioural support programme
timeFrame: First baseline to 6-months follow-up (49 weeks)
measure: Barriers and facilitators to eating a healthy, balanced diet
timeFrame: 6-months follow-up
measure: Changes in diet after 6-months of the behavioural support programme
timeFrame: First baseline to 6-months follow-up
measure: Changes in habitual diet after 6-months of the behavioural support programme
timeFrame: First baseline to 6-months follow-up
measure: Changes in weekly food shopping expenditure at 6-months follow-up will be compared with the first baseline, based on changes in reported dietary intakes
timeFrame: First baseline to 6-months follow-up
Other outcomes:
Locations:
city: London
country: United Kingdom
facility: UCL
Study officials:
affiliation: UCL, UCL Hospitals
name: Rachel L Batterham, Professor
role: PRINCIPAL_INVESTIGATOR
References: