Comparison of a very low-carbohydrate and low-fat diet on fasting lipids, LDL subclasses, insulin resistance, and postprandial lipemic responses in overweight women.
OBJECTIVE
Very low-carbohydrate diets are widely used for weight loss yet few controlled studies have determined how these diets impact cardiovascular risk factors compared to more traditional low-fat weight loss diets. The primary purpose of this study was to compare a very low-carbohydrate and a low-fat diet on fasting blood lipids, LDL subclasses, postprandial lipemia, and insulin resistance in overweight and obese women.


METHODS
Thirteen normolipidemic, moderately overweight (body fat >30%) women were prescribed two hypocaloric (-500 kcal/day) diets for 4 week periods, a very low-carbohydrate (<10% carbohydrate) and a low-fat (<30% fat) diet. The diets were consumed in a balanced and randomized fashion. Two fasting blood draws were performed on separate days and an oral fat tolerance test was performed at baseline, after the very low-carbohydrate diet, and after the low-fat diet.


RESULTS
Compared to corresponding values after the very low-carbohydrate diet, fasting total cholesterol, LDL-C, and HDL-C were significantly (p < or = 0.05) lower, whereas fasting glucose, insulin, and insulin resistance (calculated using the homeostatic model assessment) were significantly higher after the low-fat diet. Both diets significantly decreased postprandial lipemia and resulted in similar nonsignificant changes in the total cholesterol/HDL-C ratio, fasting triacylglycerols, oxidized LDL, and LDL subclass distribution.


CONCLUSIONS
Compared to a low-fat weight loss diet, a short-term very low-carbohydrate diet did not lower LDL-C but did prevent the decline in HDL-C and resulted in improved insulin sensitivity in overweight and obese, but otherwise healthy women. Small decreases in body mass improved postprandial lipemia, and therefore cardiovascular risk, independent of diet composition.
Volek
Jeff S
JS
Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, Connecticut 06269-1110, USA. jvolek@uconnvm.uconn.edu
Sharman
Matthew J
MJ
Gómez
Ana L
AL
DiPasquale
Chris
C
Roti
Melissa
M
Pumerantz
Amy
A
Kraemer
William J
WJ
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D005215:Fasting; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood*; D024821:Metabolic Syndrome / Q000097:blood / Q000178:diet therapy; D009765:Obesity / Q000097:blood* / Q000178:diet therapy*; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss / Q000502:physiology
D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D008055:Lipids; D014280:Triglycerides