None listed
Conditions
Brief summary
In the study of appetite regulation preload studies are commonly used to assess effects of the energy and macronutrient composition of a meal on subsequent hunger and food intake. In the most commonly used protocol a fixed meal containing a nutrient to be tested is given, followed several hours later by measurement of the energy consumed at an outcome meal. The participants are asked to eat freely from this meal until they are comfortably full – this is termed an ad libitum meal. If the test nutrient decreases hunger it is hypothesised that this can be detected by a decrease in energy intake at this meal. However, despite the importance of the ad lib lunch meal in appetite studies, and the wide use of this method throughout the scientific literature, there is no consensus as to the ideal composition of the meal. For example, it is not known whether the type and choice of foods offered may enhance or restrict the ability to detect changes of hunger induced by a prior test meal. It has been suggested that satiety (=feelings of fullness and decreased desire to eat) may be specific to individual sensory properties of food i.e. repeated consumption of a single food item quickly leads to decreased hunger and increased fullness and hence greater satiety. A greater variety of food items provided may be expected to result in greater intake at a meal setting. This phenomenon has become termed “sensory-specific satiety” (SSS). The predominance of data identifying the physiological mechanisms which underpin appetite control and the influence of food and nutrients on energy intake has been collected from trials run within a laboratory setting. Despite the preponderance of data in the scientific literature, a number of methodological issues within these trials remain unresolved including the design of outcome meals with the ability to discriminate changes in hunger and satiety through a behavioural change, i.e. food intake.
Interventions
This trial will investigate the effect of meal size and choice on energy intake at an ad libitum buffet lunch following 2 test meal challenges comprising (i) a low-energy, hunger-inducing test breakfast and (ii) a high-energy, hunger-suppressing test breakfast.
The trial design will be a 4 arm cross-over, single day intervention study comprising 30 healthy lean male subjects (aged 18-60 years). Participants will be given either a low energy (0.5MJ) or high energy (4.0MJ) test breakfast (matche
This trial will investigate the effect of meal size and choice on energy intake at an ad libitum buffet lunch following 2 test meal challenges comprising (i) a low-energy, hunger-inducing test breakfast and (ii) a high-energy, hunger-suppressing test breakfast. The trial design will be a 4 arm cross-over, single day intervention study comprising 30 healthy lean male subjects (aged 18-60 years). Participants will be given either a low energy (0.5MJ) or high energy (4.0MJ) test breakfast (matched for protein, fat and carbohydrate (CHO) composition (energy %)), followed by either a restricted, or multi-item buffet lunch 3 hours later. There will be a minimum washout period of 2 days in between interventions. Each participant will complete all study arms in a randomized order according to a Latin square design. The 4 interventions are: 1. Low energy (0.5MJ) breakfast, followed by restricted-item ad libitum lunch meal. 2. Low energy (0.5MJ) breakfast, followed by multi-item ad libitum lunch meal. 3. High energy (4.0MJ) breakfast, followed by restricted-item ad libitum lunch meal. 4. High energy (4.0MJ) breakfast, followed by multi-item ad libitum lunch meal. The breakfast meals will comprise typical breakfast food items consumed in New Zealand. The macronutrient compositions of the breakfasts will be: 1. Hunger-inducing Breakfast (0.5MJ)~30% Fat; ~55% CHO; 12-15% Protein. 2. Hunger-suppressing Breakfast (4.0MJ) ~30% Fat; ~55% CHO; 12-15% Protein. All breakfast items provided must be consumed by participants. The ad libitum lunch will comprise either a restricted-item buffet or a multi-item buffet. The multi-item buffet will comprise a hot savoury dish, a sandwich option, a sweet option, fruit and water. The restricted-item lunch will comprise the hot savoury dish, plus water. The macronutrient composition of both buffet meals will be approximately: Fat 20-30%; Protein 10-20% and Carbohydrate 50-60%. Both buffet lunch meals will provide items served in moderate excess and participants will be instructed to eat as much of all food items available until they feel comfortably full.
Sponsors
University of Auckland
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
1. Male 2. Age 18-60 years. 3. Lean (as defined by BMI in the range of 18-25 kg/m²). 4.Healthy, as ascertained by self-report. 5. Desire to participate in clinical trial.
Exclusion criteria
1. Significant endocrine, cardiovascular, gastrointestinal, metabolic disease or cancer/s including a history of these diseases as determined by the study physician. 2. Smokers or ex-smokers who had quit within the previous 6 months. 3. Weight loss/gain of 5kg within the previous 6 months. 4. Taking part in an active diet program such as Jenny Craig, Weight Watchers, Slim Sure, Atkins Diet, South Beach Diet etc. 5. Taking medications for weight loss or other conditions known to affect appetite regulation. 6. Any medical conditions known to affect appetite related research parameters. 7. Depression or any other anxiety disorder known to affect appetite. 8. Hypersensitivities or allergies to any foods or ingredients included in the study. 9. Blood Pressure > 160/90 mmHg. 10. Unwilling/unable to comply with study protocol. 11. Participating in another clinical intervention trial.
Outcome results
None listed