Obesity, Weight Loss
Conditions
Keywords
Weight loss, Chrono-nutrition, Diet, energy expenditure
Brief summary
This weight loss study will investigate the impact of calorie distribution across a day (large breakfast meals and smaller evening meals versus small breakfast meals and large evening meals) on body weight, and physiological and behavioral mechanisms regulating energy balance. Participants will undergo 2 x 4 week energy restriction protocols in a randomized cross over design; big breakfast (45% of calories in the morning meal, 20% at dinner) and big dinner (45% of calories in the evening meal, 20% at breakfast). We predict that timing of eating will influence energy balance, because morning energy expenditure is amplified in comparison to the evening. This study will allow us to assess whether the increased energy expenditure in the morning is linked to natural biological circadian rhythm or behavioral adaptions.
Detailed description
Dietary advice for weight management is broadly based on the assumption that a 'calorie is a calorie' and it does not matter when calories are consumed across the day. Recent evidence has challenged this assumption, suggesting that we may utilize calories more efficiently when consumed in the morning relative to the evening, and this could be used as a beneficial strategy for weight loss - this is a newly developing field of investigation which merges circadian biology with nutrition (chrono-nutrition). Timing of food consumption is a modifiable factor influencing energy balance and body weight (and thus, disease risk). Previous research has shown that calories ingested at different times of the day have different effects on energy utilization, leading to differential weight loss, even at iso-caloric amounts. This study will aim to increase our understanding of the underlying behavioral and physiological mechanisms associated with differential weight loss and energy balance when calories are consumed predominantly in the morning versus in the evening. This study will be a cross-over study comparing large breakfast versus large evening meals (percent daily calories split between breakfast, lunch and dinner as 45-35-20 (breakfast-loaded) or 20-35-45 (evening-loaded)) during energy restriction (Fed to measured RMR) on energy balance, through differences in both physiological and behavioural changes in energy expenditure and substrate utilization.
Interventions
OTHERBig Breakfast
Weight loss diet (Calories fed to measured RMR) with calories distributed predominantly at breakfast (percent daily calories split between breakfast, lunch and dinner as 45-35-20%). The diet will be high protein (30% protein, 35% fat and 35% CHO) with all meals provided.
OTHERBig Dinner
Weight loss diet (Calories fed to measured RMR) with calories distributed predominantly at dinner (percent daily calories split between breakfast, lunch and dinner as 20-35-45%). The diet will be high protein (30% protein, 35% fat and 35% CHO) with all meals provided.
Sponsors
University of Surrey
Maastricht University
University of Aberdeen
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* BMI ranging from 27-42 kg/m2; * Those habitually consuming breakfast (at least 5 times a week).
Exclusion criteria
* women who are pregnant, planning to be pregnant or breastfeeding * subjects with food allergies which prevent consumption of the study diet. * diagnosis of diabetes, hypertension, renal, hepatic, haematological disease, coronary heart disease, metabolic disease, gastrointestinal disease * having given a pint of blood for transfusion purposes within the last month * unsuitable veins for blood sampling * inability to understand the participant information sheet * inability to speak, read and understand the English language * those on any prescription medications (other than oral contraceptives) which will adversely affect the study outcomes (i.e. medications affecting, circadian timing, sleep or metabolic function). * those on any specific diet regimes * those on any weight loss programmes (that may be affecting lifestyle, physical activity and diet). * Extremes of chronotypes, sleep patterns and physical activity.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Energy balance | Measured up to day 71 of study | Change in energy balance during each diet protocol (body weight (kg)) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Resting Metabolic Rate (RMR) | Baseline,week 1, week 5, week 6, week 10. | RMR measured with indirect calorimetry (ventilated hood) |
| Thermic effect of food (TEF) | Week 1, week 5, week 6, week 10. | TEF measured with indirect calorimetry (ventilated hood) for 6 hours after a breakfast meal |
| Body Volume | Week 1, week 5, week 6, week 10. | Measured with Air Displacement plethysmography (BODPOD), |
| Bone Mineral Content | Week 1, week 5, week 6, week 10. | Measured with Dual energy x-ray absorptiometry (DEXA) |
| Total Body Water | Week 1, week 5, week 6, week 10. | Measured with deuterium dilution |
| Body Composition | Week 1, week 5, week 6, week 10. | 4 compartment model to assess changes in body composition (Combined from the measures of body weight, body volume, total body water and bone mineral) |
| Gastric emptying | Week 1, week 5, week 6, week 10. | Gastric emptying measured using stable isotope, Octanoic acid labelled breath samples. |
| Waist and hip circumference | Week 1, week 5, week 6, week 10. | Change in waist and hip circumferences and waist to hip ratio |
| Total Daily Energy Expenditure | 4 x 2 weeks. Throughout weeks 2-5 and 7-10. | Total energy expenditure measured by DLW for the 4 week BB and BD diet phases |
| Plasma glucose | Week 1, week 5, week 6, week 10. | Change in plasma fasting and 2 hr post-meal glucose |
| Plasma insulin | Week 1, week 5, week 6, week 10. | Change in plasma fasting and 2 hr post-meal insulin |
| Blood lipids | Week 1, week 5, week 6, week 10. | Change in plasma fasting and 2 hr post-meal blood lipids |
| Daily Subjective Appetite | Hourly measures for 3 days in week 1,week 5, week 6, week 10. | Changes in subjective appetite (hunger, fullness, desire to eat) measured using visual analogue scale questionnaires every waking hour for 3 days. |
| Postprandial Subjective Appetite | Week 1, week 5, week 6, week 10. | Changes in subjective appetite (hunger, fullness, desire to eat) measured using visual analogue scale questionnaires every 30 minutes for 6 hours after test meals. |
| Faecal sample analysis for gut health | Week 1, week 5, week 6, week 10. | Chronic influence on changes in gut microbiota |
| Physical activity | Measured continuously for 24 hours for 3 days in week 1,week 5, week 6, week 10. | Change in physical activity levels measured with accelerometer (actigraph) |
| 24 hour blood glucose | Measured continuously for 24 hours for 3 days in week 1,week 5, week 6, week 10. | Changes in 24 hour blood glucose levels measured with a continuous glucose monitor |
| Gut appetite hormones | Week 1, week 5, week 6, week 10. | Change in plasma fasting and 2 hr post-meal appetite hormones |
Countries
United Kingdom
Outcome results
None listed