Submitted to: Arteriosclerosis and Thrombosis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/5/1994
Publication Date: N/A
Citation: Interpretive Summary: The effect of an extremely low fat diet with and without weight loss on blood lipid levels was investigated in subjects 40 years of age or older with moderately high blood cholesterol levels. Subjects consumed a diet designed to approximate that currently consumed in the United States, a diet meeting National Cholesterol Expert Panel (NCEP) Step 2 guidelines (</=30% calories from fat, </=7% saturated fat) and a very low fat diet (LF) (15% of calories from fat). All diets were consumed in amounts that maintained body weight except for the LF diet which was consumed in amounts to both maintain body weight and result in weight loss. Blood lipid levels decreased by 13%, 7%, and 15% when subjects consumed the NCEP Step 2 diet, the LF diet when body weight was maintained and the LF diet when body weight decreased, respectively, relative to the baseline diet. Declines in low density lipoprotein (LDL) or "bad" cholesterol showed a similar pattern to that of total cholesterol but were of a somewhat greater magnitude. In contrast, high density lipoprotein (HDL) or "good" cholesterol levels decreased by 10, 25, and 18% when subjects consumed the NCEP Step 2 diet, the LF diet when body weight was maintained, and the LF diet when body weight decreased, respectively, relative to the regular American diet. These data suggest that consumption of a very low fat diet should be accompanied by weight loss to maximize the lowering of lipid levels in the blood and favorable total cholesterol to HDL cholesterol ratios.
Technical Abstract: Study subjects (6 women and 5 men) over the age of 40 years with fasting low-density lipoprotein cholesterol concentrations >130 mg/dL were studied during three 5-week diet phases and one 10-week phase: baseline (36% fat: 13% saturated fatty acids [SFA], 12% monounsaturated fatty acids [MUFA], 8% polyunsaturated fatty acids [PUFA], and 128 mg cholesterol/1000 kcal); reduced fat (29% fat: 7% SFA, 9% MUFA, 11% PUFA, and 85 mg cholesterol/1000 kcal); and two low fat (15% fat: 5% SFA, 5% MUFA, 3% PUFA, and 73 mg cholesterol/1000 kcal). Body weight was maintained during the first three 5-week phases (baseline, reduced fat, and low fat [ energy[) and decreased during the last 10-week phase when the low- fat diet was provided such that the subjects determined, in part, their caloric intake (low fat [reduced energy]) diets, respectively. Triglyceride concentrations increased from 110+/-32 to 115+/-31 (8%), 188+/-76 (75%), and 130+/-32 (22%) mg/dL when the subjects consumed the reduced-fat, low-fat, and low-fat (reduced energy) diets, respectively. Maximal changes in plasma lipid concentrations were observed after the first five weeks of the low- fat (reduced energy) diet phase despite continued weight loss throughout the entire 10-week diet period. These data suggest that very-low-fat diets (15% of calories) beneficially affect plasma lipid profiles relative to the baseline (36% of calories) or reduced-fat (29% of calories) diets only when accompanied by weight loss.