Effect of Exercise and Glycemic Index of Carbohydrate Feeding on Postprandial Lipid Metabolism

Effect of Different Types of Carbohydrates Consumed After Exercise on Blood Fat Levels

Sponsors

Lead sponsor: University of Saskatchewan

Collaborator: Heart and Stroke Foundation of Canada

Source University of Saskatchewan
Brief Summary

The increase in fat (i.e. triglyceride) in the blood after a meal is a well-established risk factor for heart disease (Nordestgaard et al. 2007). Endurance exercise is beneficial for improving the blood lipid response to a subsequent meal; that is, the appearance of fat (triglyceride) in the blood is less after a meal if endurance exercise was performed shortly before (i.e. within half a day) of the meal (Petit et al. 2003). This benefit of exercise is unfortunately negated if the after-exercise food choice to replace the calories expended during exercise is one containing high glycemic index carbohydrates. For example, if a high glycemic index carbohydrate is consumed after an evening exercise session, the exercise no longer has an effect of lowering triglyceride in the blood after a meal consumed the next morning (Harrison et al. 2009; Burton et al. 2008). Very rarely do people perform an exercise session and then fast until their next meal hours later. The more common practice is to consume food immediately after the exercise to enhance recovery and because hunger is stimulated with exercise. Consuming carbohydrate with a low glycemic index has been shown to reduce the level of fat in the blood following a subsequent meal (Gruendel et al. 2007). To date, no studies have examined the effects of consuming a low-glycemic index meal after exercise on the blood fat response to a subsequent meal. The specific objective of our research is to determine the effect of consuming low glycemic index lentils after an endurance exercise session on the blood fat (triglyceride) response to a subsequent meal. Twenty-five overweight or obese men will have their blood triglycerides measured four times over six hours after a high-fat morning meal following four different conditions, in a randomized, counterbalanced, cross-over design (i.e. the 25 subjects will each participate in all four conditions, where the order of conditions for each person is randomized): 1) After exercise (90 minutes of moderate intensity walking) is performed the evening before, followed by caloric replacement with a high-glycemic index meal (i.e. white bread and instant mashed potatoes); 2) After the same exercise is performed the evening before, followed by caloric replacement with a lentil-based meal; 3) After the same exercise is performed the evening before, followed by fasting; 4) After a no exercise/ no meal condition (i.e. control condition). In addition to measuring blood triglycerides we will measure blood insulin, free fatty acid, high density lipoproteins, low density lipoproteins, and glucose levels as these are also related to cardiovascular disease risk and may be altered with exercise and lentil consumption. We will also measure the muscle's ability to burn fat (i.e. fat oxidation) by assessing respiratory gases (oxygen consumption and carbon dioxide output) after the high-fat meal because we expect exercise and lentils to increase fat oxidation. Our expected results are that consuming lentils after endurance exercise will lower the blood triglyceride response to a subsequent meal compared to exercise alone or when high-glycemic index carbohydrates are consumed after the exercise.

Overall Status Completed
Start Date August 2013
Completion Date August 2015
Primary Completion Date August 2015
Phase N/A
Study Type Interventional
Primary Outcome
Measure Time Frame
Change in blood triglycerides Change from baseline at 6 hours
Secondary Outcome
Measure Time Frame
Change in blood glucose Change from baseline at 6 hours
Change in fat oxidation Change from baseline at 6 hours
Change in low density lipoproteins Change from baseline at 6 hours
Change in high density lipoproteins Change from baseline at 6 hours
Change in total cholesterol Change from baseline at 6 hours
Change in insulin level Change from baseline at 6 hours
Enrollment 23
Condition
Intervention

Intervention type: Behavioral

Intervention name: Exercise

Intervention type: Other

Intervention name: Diet (meal type)

Eligibility

Criteria:

Inclusion Criteria:

- Body mass index of 25 or greater

- 18-44 years of age

Exclusion Criteria:

- diabetics

- smokers

- those taking medications for cholesterol or glucose

Gender: All

Minimum age: 18 Years

Maximum age: 44 Years

Healthy volunteers: Accepts Healthy Volunteers

Overall Official
Last Name Role Affiliation
Philip D Chilibeck, Ph.D. Principal Investigator University of Saskatchewan
Location
facility University of Saskatchewan
Location Countries

Canada

Verification Date

May 2017

Responsible Party

Responsible party type: Principal Investigator

Investigator affiliation: University of Saskatchewan

Investigator full name: Phil Chilibeck

Investigator title: Ph.D.

Has Expanded Access No
Condition Browse
Number Of Arms 4
Arm Group

Arm group label: Exercise only

Arm group type: Experimental

Description: 90 minutes of exercise

Arm group label: Exercise and high glycemic index meal

Arm group type: Experimental

Description: 90 minutes of exercise followed by a high glycemic index meal matched for calories expended during the exercise

Arm group label: Exercise and low glycemic index meal

Arm group type: Experimental

Description: 90 minutes of exercise followed by a low glycemic index meal matched for calories expended during the exercise

Arm group label: No exercise and no meal

Arm group type: No Intervention

Description: No exercise and no meal

Patient Data No
Study Design Info

Allocation: Randomized

Intervention model: Crossover Assignment

Primary purpose: Basic Science

Masking: Single (Outcomes Assessor)

Source: ClinicalTrials.gov