Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.

Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Hall KD, Chen KY, Guo J et al. Journal of Nutrition. 2015 Jan;145(1):177S-83S. Epub 2014 Dec 3.
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To test two competing models of the role of carbohydrate in energy expenditure (EE) - carbohydrate-insulin model (that a carb-rich diet results in body storing carb as fat) vs "a calorie is a calorie" (that diet maconutrient variation does not affect EE or body fat); to investigate whether an isocaloric low-carbohydrate ketogenic diet (KD) is associated with changes in EE, respiratory quotient (RQ), and body composition
8 wks
"Targets E: 2394kcal/d Carb: <31g/d; 5%E Protein: 91g/d; 15%E Fat: 212g/d; 80%E Intake E: 2738kcal/d Carb: <35.8g/d; 5.2%E Protein: 104g/d Fat: 242g/d; 79.5%E "
"Baseline run-in diet Targets E: 2398kcal/d Carb: 300g/d; 50%E Protein: 91g/d; 15%E Fat: 93g/d; 35%E Intake E: 2739kcal/d Carb: 338g/d Protein: 104g/d Fat: 108g/d"
"Primary: energy expenditure (EE), respiratory quotient (RQ), and body composition. Secondary: urinary measures including fasting and daily insulin secretion (C-peptide), urea, ketones, nitrogen, creatinine; metabolite and hormone concentrations including fatty acids, glucose, triglycerides, glucagon, leptin."
"NR "
"EE WG: NR BG: Y K diet: 2676kcal/d B diet: 2619 p<0.0004 SEE K diet: 1658kcal/d B diet: 1569 p<0.0001"
"The isocaloric K diet was not accompanied by increased body fat loss but was associated with relatively small increases in EE that were near the limits of detection with the use of state-of-the-art technology."


AHA - American Heart Association;
ALT - alanine aminotransferase;
AMDR - acceptable macronutrient distribution range;
AST - aspartate aminotransferase;
BG - between study groups;
BHOB - beta-hydroxybutyrate;
DBP - diastolic blood pressure;
E- energy, caloric intake;
eGFR - estimated glomerular filtration rate;
FBG - fasting blood glucose;
GGT - gamma-glutamyl transferase;
HDL-C - high-density lipoprotein cholesterol;
iGFR - isotope glomerurar filtration rate;
LDL-C - low-density lipoprotein cholesterol;
NAFLD - non-alcoholic fatty liver disease;
NR - not reported (or data needed for calculation not available);
N - no;
NA - not applicable;
NS - not specified;
NSS - not statistically significant;
SBP - systolic blood pressure;
SS - statistically significant;
TG - triglyceride;
total C - total cholesterol;
V - varied, mixed;
WG - within a study group;
WMD - weighted mean difference;
Y - yes

Number of People in Studies:

3,296 Enrolled in randomized controlled trials on 25% or less carbohydrates
2,626 Completed randomized controlled trials on 25% or less carbohydrates
79.67% 82% completion of studies

Duration of Trial

<6 Months
6-9 Months
1 -2 years
>2 years

# of Trials


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