Study of the Effect of a Very-Low-Carbohydrate Diet on Energy Expenditure
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|ClinicalTrials.gov Identifier: NCT01967563|
Recruitment Status : Completed
First Posted : October 23, 2013
Last Update Posted : October 13, 2022
- Popular weight loss plans often restrict carbohydrates or fat. Research shows that very-low-carbohydrate (ketogenic) diets lead to greater weight loss than low-fat diets. Researchers want to know if eating fewer carbohydrates changes the number of calories the body uses. They also want to know how a ketogenic diet affects hunger, hormones, and food preferences.
- To better understand how the body responds to different diets.
- Men 18 to 50 years old who are healthy but overweight.
Participants will have 3 screening visits:
- Medical history, physical exam, blood test, and EKG. They will eat during the visit.
- For the week before the visit, participants will wear physical activity monitors daily. They will record everything they eat and sample the special diet. At the visit, they will receive an EKG and heart rate test while biking for 30 minutes.
- For the week before the visit, participants will wear the physical activity monitors. They will eat all their meals from the special diet that will be provided. At the visit, they will answer questions and bike for 60 minutes.
- After screening, for 1 week, participants will visit the clinic daily to receive that day s food. They will not eat or drink anything else except water.
- Then participants will stay at the clinic for 8 weeks. They cannot leave but can have visitors. Participants will wear physical activity monitors, bike daily, and follow different diets. Tests will be given daily, and may include weighing, X-rays, and blood and urine tests. They will spend several days in a monitored room to test oxygen and carbon dioxide.
|Condition or disease|
|Obesity Appetite Healthy Volunteers|
Popular weight loss strategies often prescribe targeted reduction of dietary carbohydrate or fat. Recent clinical trials in obese subjects have found that low-carbohydrate diets result in greater weight loss compared with low-fat diets on a time scale of months when diet adherence was likely the highest. One hypothesis regarding the mechanism of improved weight loss with low carbohydrate diets is that such diets significantly modify the body s hormonal milieu to influence metabolic regulation and energy expenditure. Low-carbohydrate diets may thereby offer a metabolic advantage over low fat diets. In addition, low-carbohydrate diets may also decrease hunger or increase satiety compared to low-fat diets.
Determining the mechanism whereby one diet leads to greater weight loss than another is hampered by the inability to accurately measure food intake or physical activity in an outpatient setting. Thus, an inpatient feeding study lasting many weeks is required to accurately measure energy balance differences between isocaloric diets that differ in macronutrient composition. In this pilot multicenter cross-over study in 16 overweight and class I obese men, we will measure changes in energy expenditure in response to 4 weeks of inpatient feeding of a eucaloric, very low carbohydrate, ketogenic diet (5% Carbohydrate, 15% Protein, 80% Fat) immediately following an inpatient period of at least 4 weeks of consuming an energy balanced standard American diet (50% Carbohydrate, 15 % Protein, 35% Fat).
|Study Type :||Observational|
|Actual Enrollment :||5 participants|
|Official Title:||Effect of a Eucaloric Ketogenic Diet on Energy Expenditure: A Pilot Study|
|Actual Study Start Date :||December 3, 2013|
|Actual Primary Completion Date :||February 23, 2015|
|Actual Study Completion Date :||February 23, 2015|
overweight and class I obese adult male volunteers
Adult Male Subjects will be recruited to determine the effects on energy expenditure of transitioning from an energy-and macronutrient-balanced standard baseline diet to a eucaloric ketogenic diet
- To determine 24hr energy expenditure, respiratory quotient, and sleeping energy expenditure following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet. [ Time Frame: 1 year ]the subjects will spend the 4th, 5th, 11th, 12th, 18th, 19th, 25th and 26th days of Stages 2 & 3 in the metabolic chamber to measure 24-hour energy expenditure and sleeping energy expenditure. The energy expenditure calculations will be corrected for urinary ketone excretion since approximately 0.33 L of O2 is consumed for every gram of ketone excreted in the urine.
- To investigate changes in body composition and appetitive behaviors such as hunger, satiety, food impulsivity, and food liking & wanting during a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced stan... [ Time Frame: 7 days(outpatient) plus 8 weeks( inpatient) ]hunger and satiety assessments will be completed multiple times each day, and ad libitum meal tests and appetitive computer tasks (delay discounting, liking & wanting, go/no-go, food choice) will be performed during the latter periods of Stages 2 & 3.
- To determine body weight and body composition following a 4-week eucaloric ketogenic diet as compared to 4 weeks of consuming an energy-balanced standard diet. [ Time Frame: 7 days (outpatient) plus 8 weeks (inpatient) ]measurement of body composition by DXA, isotope dilution, and air-displacement plethysmography (BodPod) will be performed on the 15th and 28th days of Stages 2 & 3. Measurement of total body water by administering deuterium oxide will be performed on the 28th day of Stages 2 & 3. Body weight will be measured daily.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01967563
|United States, Maryland|
|National Institutes of Health Clinical Center|
|Bethesda, Maryland, United States, 20892|
|Principal Investigator:||Kevin Hall, Ph.D.||National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)|