Exercise Effects on Insulin, Gut Peptides, and Appetite

Study Overview
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Brief Summary
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Determine whether the mid-day suppression of hunger and amplified increase in the release of glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1) following morning exercise is due to increased fat content of the diet per se or a combination of high fat diet after morning exercise. The action of gut peptides, particularly GLP-1, on gastric emptying is likely to be important in mediating its effects on postprandial appetite and glycemia (Nauck et al. 1997). Our hypothesis is that exercise amplifies gut peptide secretion when diet is enriched with fat, and that this stimulus suppresses the hunger sensation.

Detailed Description
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Specific aim: Determine whether a change in macronutrient composition from 60% carbohydrate and 25% fat to 30% carbohydrate and 45% fat is responsible by itself for suppression of hunger and increased secretory response of glucose-dependent insulinotropic hormone (GIP) and glucagon-like peptide-1 (GLP-1), or whether these changes depend on preceding exercise. We will measure (a) concentrations of plasma GIP and GLP-1 by chemiluminescent multiplex assay, (b) concentrations of plasma ancetaminophen to assess the gastric emptying rate, (c) concentrations of plasma insulin, and glucagon by radioimmunoassay, and glucose, ketone bodies, and free fatty acids with appropriate spectrophotometric methods, (d) hourly appetite responses with visual analog scale under two conditions: sedentary (SED) and exercise (EX). Hypothesis: Hunger suppression and secretion of GIP and GLP-1 after the morning meal will be greater with slower gastric emptying rate when a meal consisting of 45% fat and 30% carbohydrate follows three hours after a 2-hour bout of moderate-intensity exercise than in the absence of exercise.

Official Title
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The Exercise Effects on Appetite and Gut Peptides While on High-fat Diet

Conditions
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Endocrine and Metabolic Responses to Exercise and Diets

Intervention / Treatment
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* Other: Exercise and diets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Postmenopausal status Age 50 to 65 years BMI between 20 and 30 kg/m2. Good health status (normotensive, fasting glucose < 100 mg/dl, , hematocrit > 32%, hemoglobin >12 mg/dl) Absence of restricted food intake Absence of endocrine and metabolic disorders requiring medication other than hormonally corrected hypothyroidism Absence of musculoskeletal disabilities that would prevent walking Exclusion Criteria: Presence of endocrine and metabolic disease requiring medication, other than hormonally corrected hypothyroidism Presence of musculoskeletal disabilities that would prevent walking Smoking Active dieting Absence of listed inclusion criteria Unwillingness to follow study protocol.

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

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: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Exercise-high-fat diet<br>Two bouts of exercise followed by a high-fat meal | Other: Exercise and diets<br>* Exercise and high-fat diet Exercise and high-carbohydrate diet Sedentary and high-fat diet Sedentary and high-carbohydrate diet<br>|
| Experimental: Exercise-high-carbohydrate diet<br>Two bouts of exercise followed by a high-carbohydrate meal | Other: Exercise and diets<br>* Exercise and high-fat diet Exercise and high-carbohydrate diet Sedentary and high-fat diet Sedentary and high-carbohydrate diet<br>|
| Experimental: Sedentary-high-fat diet<br>Sedentary trial with two high-fat meals | Other: Exercise and diets<br>* Exercise and high-fat diet Exercise and high-carbohydrate diet Sedentary and high-fat diet Sedentary and high-carbohydrate diet<br>|
| Experimental: Sedentary-high-carbohydrate diet<br>Sedentary trial with two high-carbohydrate meals | Other: Exercise and diets<br>* Exercise and high-fat diet Exercise and high-carbohydrate diet Sedentary and high-fat diet Sedentary and high-carbohydrate diet<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma insulin concentration | Change in plasma insulin to two bouts of exercise followed by a high-carbohydrate or a high fat diet | 36 hours | 
| Plasma glucagon concentration | Changes in plasma glucagon concentration to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| Plasma concentration of glucose-dependent insulinotropic peptide (GIP) | Changes in plasma concentration of glucose-dependent insulinotropic peptide (GIP)to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| Plasma concentration of free fatty acids | Changes in plasma concentration of free fatty acidsto two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| Plasma concentration of beta-hydroxybutyrate | Changes in plasma concentration of beta-hydroxybutyrate to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| Plasma glucose concentration | Changes in plasma glucose concentration to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| daytime hourly appetite ratings | Changes in daytime hourly appetite ratings to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma concentrations of glucagon-like peptide-1 (GLP-1) | Changes in plasma concentrations of glucagon-like peptide-1 (GLP-1)to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 
| Plasma concentrations of peptide tyrosine tyrosine (PYY) | Changes in plasma concentrations of peptide tyrosine tyrosine (PYY) to two bouts of exercise followed by either a high-carbohydrate or a high-fat meal | 36 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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exercise, high carbohydrate and high fat diets, insulin, gut peptides, appetite, metabolism, glucose