Glycogen and Appetite

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

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.

Study Overview

• Status: Completed
• Conditions: Energy Intake
• Intervention / Treatment: Other: Placebo; Dietary supplement: Exercise plus carbohydrate; Dietary supplement: Exercise plus niacin

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Bath, United Kingdom, BA2 7AY
    • Department for Health, University of Bath

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

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)

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Control; 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; 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.
Active Comparator: Exercise plus carbohydrate; 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; A high carbohydrate drink to be consumed 1 hour prior to exercise and every 15 minutes during exercise.
Experimental: Exercise plus niacin; 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; A dose of niacin to be consumed 30 minutes prior to exercise, at onset of exercise and 30 minutes into exercise.

What is the study measuring?

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

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in plasma GLP-1 concentrations post exercise	Incremental area under the curve of plasma GLP-1 concentrations	2 hours
Change in plasma leptin concentrations post exercise	Incremental area under the curve of plasma leptin concentrations	2 hours
Change in plasma insulin concentrations during exercise	Incremental area under the curve for plasma insulin concentrations	1 hour
Change in plasma non-esterified fatty acid concentrations during exercise	Incremental area under the curve for plasma non-esterified fatty acid concentrations	1 hour
Change in plasma glucose concentrations during exercise	Incremental area under the curve for plasma glucose concentrations	1 hour
Change in plasma lactate concentrations during exercise	Incremental area under the curve for plasma lactate concentrations	1 hour
Change in carbohydrate oxidation during exercise	Incremental area under the curve for carbohydrate oxidation	1 hour
Change in fat oxidation during exercise	Incremental area under the curve for fat oxidation	1 hour
Change in skin temperature during exercise	Incremental area under the curve for skin temperature	1 hour
Change in core body temperature during exercise	Incremental area under the curve for core body temperature	1 hour
Muscle glycogen utilisation	Difference in muscle glycogen utilisation during exercise between conditions	1 hour
Extra-muscular glycogen oxidation	Difference in extra muscular glycogen oxidation during exercise between conditions	1 hour
Difference in blood pressure between conditions	Difference in blood pressure between conditions	3 hours

Collaborators and Investigators

• Sponsor: University of Bath

Study record dates

Study Major Dates

• Study Start (Actual): October 10, 2022
• Primary Completion (Actual): March 15, 2024
• Study Completion (Actual): August 30, 2024

Study Registration Dates

• First Submitted: May 17, 2022
• First Submitted That Met QC Criteria: June 12, 2022
• First Posted (Actual): June 14, 2022

Study Record Updates

• Last Update Posted (Actual): March 27, 2025
• Last Update Submitted That Met QC Criteria: March 24, 2025
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Antimetabolites; Micronutrients; Vitamin B Complex; Vitamins; Vasodilator Agents; Hypolipidemic Agents; Lipid Regulating Agents; Niacin
• Other Study ID Numbers: EIRA1-7142

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No