An observational study in Obesity, Appetite and Healthy Volunteers, sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Terminated at 1 site in United States. Open to male participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2025-04-22.
Sponsored by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) · Observational
Background:
Objectives:
Eligibility:
Design:
Participants will have 3 screening visits:
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).
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This study's enrollment of 5 is below the median of 135 across 1,283 observational studies indexed under Obesity.
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We will study the magnitude and variability of energy expenditure changes in response to a eucaloric ketogenic diet subsequent to a standard energy- and macronutrient-balanced diet in overweight and class I obese adult male volunteers
EXCLUSION CRITERIA:
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.
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.
Time frame: 1 year
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...
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.
Time frame: 7 days(outpatient) plus 8 weeks( inpatient)
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.
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.
Time frame: 7 days (outpatient) plus 8 weeks (inpatient)
This study is terminated, as verified in Apr 2025. You cannot join it, but the record below documents what was studied.
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National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)