Exercise Effects on Insulin, Gut Peptides, and Appetite (XFG)

University of Michigan

Status: Completed

Conditions: Endocrine and Metabolic Responses to Exercise and Diets

Treatments: Other: Exercise and diets

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT01891617

R15DK082800 (U.S. NIH Grant/Contract)

R15DK082800-XFG

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 16 patients

Sex: Female

Ages: 50 to 65 years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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16 participants in 4 patient groups

Exercise-high-fat diet

Experimental group

Description:

Two bouts of exercise followed by a high-fat meal

Treatment:

Other: Exercise and diets

Exercise-high-carbohydrate diet

Experimental group

Description:

Two bouts of exercise followed by a high-carbohydrate meal

Treatment:

Other: Exercise and diets

Sedentary-high-fat diet

Experimental group

Description:

Sedentary trial with two high-fat meals

Treatment:

Other: Exercise and diets

Sedentary-high-carbohydrate diet

Experimental group

Description:

Sedentary trial with two high-carbohydrate meals

Treatment:

Other: Exercise and diets