Thermic & Lipemic Properties of Dietary Carbohydrates

Not Applicable

Completed

• Conditions: Exogenous Obesity; Dietary Modification
• Interventions: Other: High Glycemic Index meals; Other: Low Glycemic Index meals

• Registration Number: NCT01354574
• Lead Sponsor: USDA, Western Human Nutrition Research Center

Brief Summary

The purpose of this study is to determine if consumption of meals containing carbohydrates with different glycemic index (a high glycemic index meal and a low glycemic index meal)have different effects on energy expenditure, type of metabolic fuels used for energy, blood lipids and lipoproteins, and sensations of hunger, fullness, and the hormones related to satiety.

Detailed Description

Little is known about the metabolic effects of chronic dieting and weight cycling in humans, but limited evidence suggests that fatty acid oxidation may be depressed leading to periodic elevation of circulating lipids associated with meal ingestion and preferential storage of fat in adipose tissue. With the traditional approach of restrictive dieting failing to result in permanent weight loss and, possibly producing abnormalities in lipid metabolism, it is important to evaluate alternative approaches to achieve a healthy body weight through improved metabolism. In this study the investigators will test the postprandial metabolic effects of standard mixed meals containing carbohydrates with high glycemic index and compare these effects to responses obtained with standard mixed meals, matched for protein and fat content but containing carbohydrates with low glycemic index.

Study Timeline

• Study Start: 2002-10
• Primary Completion: 2005-06
• Study Completion: 2005-06
• Study First Submitted: 2010-08-13
• Study First Submitted QC: 2011-05-16
• Study First Posted: 2011-05-17
• Status Verified: 2011-07
• Last Update Submitted: 2011-07-12
• Last Update Posted: 2011-07-13

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 28

Inclusion Criteria

• Body mass index between 25 and 30 kg/m2
• Having regular menses
• Willing to refrain from restrictive dieting during the course of the study

Exclusion Criteria

• Pregnant or currently planning a pregnancy
• Cigarette smoking
• Taking medications to induce weight loss or change appetite
• History of cardiovascular disease
• History of metabolic disorders, including diabetes

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
High Glycemic Index meals	High Glycemic Index meals	Three days of run-in diet with meals containing high glycemic index carbohydrates followed by test day with breakfast meal containing high glycemic index carbohydrates.
Low Glycemic Index meals	Low Glycemic Index meals	Three days of run-in diet with meals containing low glycemic index carbohydrates followed by test day with breakfast meal containing low glycemic index carbohydrates.

Primary Outcome Measures

Name	Time	Method
Respiratory Gas Exchange	30 minutes before a standardized test meal and intermittently for 480 minutes following the meal.	Respiratory Gas Exchange will be measured using an automated metabolic cart. Gas analyzers and volumeter will be calibrated using manufacturer's procedures.

Secondary Outcome Measures

Name	Time	Method
Plasma glucose	10 blood samples taken over a 480 minute period.	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of standardized test meal.
Circulating lipoproteins	4 blood samples taken over a 480 minute period	Blood samples for lipoprotein analyses were taken at fasting (0 minute) and at 150, 210, and 480 minutes following consumption of test meal. A subset of 10 randomly-selected subjects was chosen for this outcome measure
Subjective evaluation of appetite	16 timepoints measured over 600 minutes	Visual analog scales were used to assess appetite-related sensations. Four responses were obtained during the fasting phase (120 minutes) and 12 responses were obtained in the 480 minute postprandial period.
Food consumption at a buffet-style meal	at 480 minutes following test meal	The amount and types of foods consumed were measured after subject was presented with a buffet-style meal.
Body composition	measured the morning of the standard meal challenge	Body composition (fat mass, % fat, lean mass, bone density) will be measured using dual energy x-ray absorptiometry.
Serum insulin	10 blood samples taken over a 480 minute time period	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of test meal.
Plasma leptin	10 blood samples taken over a 480 minute period	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of test meal.
Plasma ghrelin	10 blood samples taken over a 480 minute time period	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of test meal.
Cholecystokinin (CCK)	10 blood samples taken over a 480 minute time period	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of test meal.
GLP-1	10 blood samples taken over a 480 minute time period	1 fasting blood sample (0 minutes) and 9 post-prandial blood samples taken at 30, 60, 90, 120, 150, 210, 270, 360 and 480 minutes following consumption of test meal.

Trial Locations

Locations (1)

Western Human Nutrition Research Center; 🇺🇸 Davis, California, United States