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

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

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.

Study Overview

• Status: Completed
• Conditions: Hyperlipidemia
• Intervention / Treatment: Behavioral: Exercise; Other: Diet (meal type)

• Study Type: Interventional
• Enrollment (Actual): 23
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Saskatchewan
    • Saskatoon, Saskatchewan, Canada, S7N 5B2
      • University of Saskatchewan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 44 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Exercise only; 90 minutes of exercise	Behavioral: Exercise
Experimental: Exercise and high glycemic index meal; 90 minutes of exercise followed by a high glycemic index meal matched for calories expended during the exercise	Behavioral: Exercise; Other: Diet (meal type)
Experimental: Exercise and low glycemic index meal; 90 minutes of exercise followed by a low glycemic index meal matched for calories expended during the exercise	Behavioral: Exercise; Other: Diet (meal type)
No Intervention: No exercise and no meal

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in blood triglycerides	Change from baseline at 6 hours

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: University of Saskatchewan
• Collaborators: Heart and Stroke Foundation of Canada

Study record dates

Study Major Dates

• Study Start: August 1, 2013
• Primary Completion (Actual): August 1, 2015
• Study Completion (Actual): August 1, 2015

Study Registration Dates

• First Submitted: August 15, 2013
• First Submitted That Met QC Criteria: December 10, 2013
• First Posted (Estimate): December 16, 2013

Study Record Updates

• Last Update Posted (Actual): May 5, 2017
• Last Update Submitted That Met QC Criteria: May 2, 2017
• Last Verified: May 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Lipid Metabolism Disorders; Dyslipidemias; Hyperlipidemias
• Other Study ID Numbers: 000041

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO