The effect of protein intake on 24-h energy expenditure during energy restriction.
OBJECTIVE
To investigate whether protein intake influences the decline in energy expenditure during energy restriction.


METHODS
Cross-over study of three diets of 4.2 MJ/d for 7 days: one diet with 36% energy as protein and two with 15% energy as protein, one high in carbohydrate and the other high in fat.


METHODS
Two men and six women aged 31-57 y. BMI 27.B-34.1 kg/m2.


METHODS
24-h energy expenditure (24-h EE), sleeping metabolic rate (SMR) and body weight on days 0 and 7 of each diet; 24-h urinary nitrogen excretion (24-h UN) on days 0-7 of each diet.


RESULTS
24-h EE and SMR declined on all three diets but the decrease was significantly less on the high protein diet than on the two low protein diets. Weight loss was similar on all three diets. 24-h UN was less than N intake on the high protein diet but greater than N intake on the two low protein diets.


CONCLUSIONS
Maintaining protein intake reduces the decrease in energy expenditure during energy restriction.
Whitehead
J M
JM
Human Nutrition Unit, Rowett Research Institute, Aberdeen, UK.
McNeill
G
G
Smith
J S
JS
D000328:Adult; D000886:Anthropometry; D001806:Blood Urea Nitrogen; D001835:Body Weight / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D018753:Diet, Protein-Restricted; D004041:Dietary Fats / Q000494:pharmacology; D004043:Dietary Fiber / Q000494:pharmacology; D004044:Dietary Proteins / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology
D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins