Effects of an 8-week high-protein or high-carbohydrate diet in adults with hyperinsulinemia.
BACKGROUND
Incidence of insulin resistance (IR) in Americans is steadily rising. IR may be ameliorated with < or = 5% loss in body weight.


OBJECTIVE
To examine effects of 2 weight-loss diets on body weight and composition in overweight adults with IR.


METHODS
Participants randomly assigned to a high-protein, low-fat (HPLF) or a high-carbohydrate, low-fat (HCLF) diet for 8 weeks.


METHODS
All meals prepared and weighed in the metabolic kitchen at Arizona State University. Lunch consumed on-site; all other meals packaged for home consumption.


METHODS
Twenty overweight, healthy participants with elevated fasting serum insulin (> or = 15 microU/L) were recruited.


METHODS
Both diets were low-fat (27% kcal from fat; < 7% saturated, < or = 10% monounsaturated, and < or = 10% polyunsaturated) and energy-restricted (energy levels were 1200, 1500, 1700 or 2000 kcal); HPLF: 32% protein, 41% carbohydrate; HCLF: 59% carbohydrate, 14% protein. Energy levels were assigned on the basis of participant's resting metabolic rate.


METHODS
Body composition, etabolic indices, fasting plasma glucose, and insulin.


RESULTS
No significant differences were found in the main outcome measures between the diets. Body weight (HPLF: -4.9 kg; HCLF: -4.0 kg) and total percent body fat (HPLF: -1.5%; HCLF: -0.4%) significantly reduced from baseline to week 8 (P = .005 and P = .035, respectively).


CONCLUSIONS
Both diets promoted > or = 5% loss in body weight and significantly reduced percent body fat.
Kleiner
Rima E
RE
Department of Nutrition, Arizona State University, Mesa, Arizona, USA.
Hutchins
Andrea M
AM
Johnston
Carol S
CS
Swan
Pamela D
PD
D000328:Adult; D001835:Body Weight / Q000502:physiology; D004038:Diet, Reducing / Q000379:methods; D004040:Dietary Carbohydrates / Q000627:therapeutic use*; D004044:Dietary Proteins / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000178:diet therapy*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000178:diet therapy; D013997:Time Factors
D004040:Dietary Carbohydrates; D004044:Dietary Proteins