Fatty Acid Metabolism and Insulin Sensitivity: the Role of Endurance Exercise

Summary

Clearly the effects of diet and exercise are beneficial for obese persons, but the underlying mechanisms for the improvements in metabolic health are not completely clear. Although mounting evidence suggests that alterations in lipid metabolism in persons with abdominal obesity are associated with a several medical complications, including diabetes, little is known about the factors responsible for this effect. The project in this application is designed to examine how the addition of endurance exercise training to a weight-loss program alters whole-body fatty acid availability, uptake, and oxidation as well as the expression of cellular factors that regulate these processes. In addition, we will evaluate whether these alterations are associated with improvements in insulin sensitivity. In the end, these experiments will provide insight into the cellular and whole-body adaptations in fatty acid metabolism in response to weight-loss and exercise training that may lead to enhancement of insulin sensitivity. Identifying relationships between gene expression, whole-body fatty acid metabolism and clinical outcome measurements, such as insulin sensitivity, may lead to improvements in the therapeutic and/or the preventative approach to obesity and its co-morbidities.

Conditions

• Insulin Resistance and Type 2 Diabetes

Interventions

BEHAVIORAL

Weight loss - diet only

Subjects adhere to a reduced calorie diet until they lose exactly 12% of their initial body weight. After they achieve this weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.

BEHAVIORAL

Weight loss plus exercise

Subjects adhere to a reduced calorie diet and perform 4 session of endurance exercise training per week until they lose exactly 12% of their initial body weight. Exercise training consists of stationary bicycle exercise. the exercise duration and intensity ramp up over the first few weeks of training until subjects exercise 45 min per session at an intensity of 85% of their maximal heart rate. 3 of the 4 exercise session each week are supervised by an Exercise physiologist. After they achieve the 12% weight loss goal, they are placed on a weight-maintaining diet for 3-4 weeks before follow-up experiments are performed. Subjects meet weekly with a research dietitian throughout their weigh-loss and weight maintenance program.

Sponsors & Collaborators

• American Diabetes Association

  collaborator OTHER

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

  collaborator NIH

• University of Michigan

  lead OTHER

Principal Investigators

• Jeffrey Horowitz, PhD · University of Michigan

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2003-06-30

Primary Completion

2007-01-31

Completion

2007-01-31

Countries

• United States

Study Locations