Effects of Diet Changes on Metabolism
|First Received Date ICMJE||August 30, 2007|
|Last Updated Date||May 8, 2014|
|Start Date ICMJE||August 2007|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE||Not Provided|
|Original Primary Outcome Measures ICMJE||Not Provided|
|Change History||Complete list of historical versions of study NCT00523627 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE||Not Provided|
|Original Secondary Outcome Measures ICMJE||Not Provided|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Effects of Diet Changes on Metabolism|
|Official Title ICMJE||Study of Short-Term Metabolic Adaptation: Prediction of Weight Change and Effects of Macronutrient Manipulations|
This study, conducted at the NIH Clinical Research Unit at the Phoenix Indian Medical Center, will examine how the body s metabolism (energy expenditure) changes when people overeat and when they fast and how different diets (e.g., high-protein or high-fat) affect metabolism. The results may provide information about whether there are mechanisms that make some people more resistant than others to gaining weight when they eat more.
Non-smoking healthy subjects between 18 and 55 years of age who weigh no more than 350 pounds may be eligible for this study. Participants undergo the following procedures:
Some participants are asked to volunteer to repeat two of the chamber studies to validate the measurements. The repeat session includes only the fasting and the overfeeding with normal protein content.
All participants are followed at 6 months with blood tests, a DEXA scan, and urine tests (including pregnancy test for women). At annual visits for years 1 through 7, participants have the 6-month tests plus an oral glucose tolerance test.
Some people appear to be more resistant than others to gaining weight when they overeat, though they do not increase their physical activity. This may indicate that adaptive mechanisms exist, which lead to wasting as heat part of the excess calories taken in. Such mechanisms exist in rodents including activation of brown fat, a tissue which can also convert calories to heat for warmth. Human studies have provided conflicting results. A pilot study on the relationship of the weight change over time with the changes in the amount of energy an individual uses over 24 hours (energy expenditure, EE) with 48-h overfeeding (OF) and fasting (F) in Pima Indian men has shown that persons with the greatest increase in EE with OF and the smallest decrease in EE with F gained the least weight over time, indicating that the ability to waste more calories when overfed may reduce weight gain. Other studies, however, have not shown this relationship. In addition, it has been proposed that unbalanced diets can help magnify these effects. The aims of this study are to test whether (a) the changes in EE in response to 24-h OF and F predict changes in weight over two years, and (b) high-carbohydrate diets or diets with high or low protein amounts may magnify the metabolic response to 24-h OF compared to normal protein and high-fat diets. 64 volunteers will be evaluated at baseline, 6 months and on a yearly basis for up to 7 years. At baseline, subjects will undergo 8 24-h sessions in a human respiratory chamber to measure EE while on a weight-maintaining diet, and then in random order: fasting, 200% OF on a normal-protein diet, 200% OF on a high fat, low-protein diet, 200% OF on a high-fat, normal-protein diet, 200% OF on a high fat, high protein diet, and 200% OF on a high-carbohydrate, normal-protein diet. Twenty volunteers will have two additional chambers to try to understand what influences how a person responds to overeating. Fifteen volunteers will have two additional chambers to try and understand if the source of carbohydrates, i.e. simple sugars versus complex carbohydrates, in a high carbohydrate diet affect metabolism. Thirty volunteers will also undergo 2 positron emission tomography (PET) studies to look at the relationship of brown fat with EE in adult humans. Body weight and composition will be measured at each subsequent admission. Hormonal measurements to find determinants of adaptive changes in EE in response to OF and F will also be performed. This study will provide significant insights into possible mechanisms that may help people resist weight gain and obesity.
|Study Type ICMJE||Observational|
|Study Design ICMJE||Time Perspective: Prospective|
|Target Follow-Up Duration||Not Provided|
|Sampling Method||Not Provided|
|Study Population||Not Provided|
|Intervention ICMJE||Not Provided|
|Study Group/Cohort (s)||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Recruiting|
|Estimated Enrollment ICMJE||105|
|Completion Date||Not Provided|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
Prior to beginning any of the study procedures, all subjects will be fully informed of the aim, nature, and risks of the study prior to giving written informed consent. The study s informed consent will be obtained by a principal or associate investigator, research physician or physician assistant working in the clinical research unit.
|Ages||18 Years to 55 Years|
|Accepts Healthy Volunteers||Yes|
|Location Countries ICMJE||United States|
|NCT Number ICMJE||NCT00523627|
|Other Study ID Numbers ICMJE||999907215, 07-DK-N215|
|Has Data Monitoring Committee||Not Provided|
|Responsible Party||Not Provided|
|Study Sponsor ICMJE||National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)|
|Collaborators ICMJE||Not Provided|
|Information Provided By||National Institutes of Health Clinical Center (CC)|
|Verification Date||April 2014|
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP