Glycogen and Appetite

Study Overview
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Brief Summary
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Obesity is the outcome of chronic excessive energy intake and reduced energy expenditure leading to energy imbalance. It is a risk factor for many preventable diseases such as metabolic disease and its consequences such as type 2 diabetes and cardiovascular disease. Sedentary adults have been shown to have an increased appetite in excess of energy requirements and adults who are more active are able to better regulate energy intake. It is thought that carbohydrate availability and specifically hepatic glycogen utilisation during exercise is a regulator of appetite. However, the majority of research so far does not support this theory, potentially due to research not examining the tissue-specific link between glycogen use and appetite. The aim of this study is to assess whether altering substrate utilisation during exercise by suppressing lipolysis influences GLP-1 levels and caloric intake post exercise. Additionally, the study will explore if there is a tissue specific link between substrate utilisation and post exercise energy intake and examine potential sex differences.

Official Title
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The Effect of Suppression of Adipose Lipolysis on GLP-1 and Energy Intake in Men and Women

Conditions
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Energy Intake

Intervention / Treatment
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* Dietary Supplement: Exercise plus carbohydrate
* Dietary Supplement: Exercise plus niacin
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males aged 18-60 and premenopausal women Physically active (at least 30 minutes of exercise 3 times a week) Body mass index 18.0-30.0 kg·m-2 Exclusion Criteria: Weight instability (>5kg change in body mass over last 6 months) Restrained eater (e.g. limiting food intake, calorie counting) Current smoker Aversion or allergy to test meal foods Pregnant or lactating Amenorrhoea in women Any medical condition or medication that could introduce bias into the study (e.g., diabetes, CVD, lipid or glucose metabolism altering medications) Any cardiopulmonary condition prohibiting exercise testing Any contraindication to niacin or aspirin (e.g., diabetes, gout, clotting disorders, allergy to non-steroidal anti-inflammatory drugs)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control<br>A placebo drink to be consumed 1 hour prior to exercise and every 15 minutes during exercise and placebo tablets to be consumed 30 minutes prior to exercise, at the onset of exercise and 30 minutes into exercise. | Other: Placebo<br>* A placebo drink to be consumed 1 hour prior to exercise and every 15 minutes during exercise and placebo tablets to be consumed 30 minutes prior to exercise, at the onset of exercise and 30 minutes into exercise.<br>|
| Active Comparator: Exercise plus carbohydrate<br>A high carbohydrate drink (1.6g/kg) to be consumed 1 hour prior to exercise and further drinks (0.2g/kg) every 15 minutes during exercise. | Dietary Supplement: Exercise plus carbohydrate<br>* A high carbohydrate drink to be consumed 1 hour prior to exercise and every 15 minutes during exercise.<br>|
| Experimental: Exercise plus niacin<br>A dose of niacin (10mg/kg) to be consumed 30 minutes prior to exercise and two further doses (5mg/kg) at the onset of exercise and 30 minutes into exercise. | Dietary Supplement: Exercise plus niacin<br>* A dose of niacin to be consumed 30 minutes prior to exercise, at onset of exercise and 30 minutes into exercise.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in ad libitum energy intake | Difference between ad libitum energy intake (kcal) post exercise between trials | 2 hours post exercise |