AMA 1995 Nov 8;274(18):1450-1455

Body weight and low-density lipoprotein
cholesterol changes after consumption of a
low-fat ad libitum diet.

Schaefer EJ, Lichtenstein AH, Lamon-Fava S, McNamara JR,
Schaefer MM, Rasmussen H, Ordovas JM

OBJECTIVE--To assess the effects of a diet restricted in fat, saturated
fat, and cholesterol, under weight-maintenance and ad libitum
conditions on body weight and plasma lipid levels in
hypercholesterolemic subjects. DESIGN--Dietary intervention study.

SETTING AND PARTICIPANTS--Twenty-seven free-living,
healthy middle-aged and elderly men (n = 13, age range, 41 to 81 years)
and women (n = 14, age range, 52 to 79 years) with moderate
hypercholesterolemia (low-density lipoprotein cholesterol [LDL-C] >
or = 3.36 mmol/L [130 mg/dL]) participated in the study.

INTERVENTION--Subjects underwent three dietary phases. First,
subjects were provided with a diet similar to the average US diet
(baseline diet; 35.4% total fat, 13.8% to 14.1% saturated fat, and 30 to 35
mg/1000 kJ [128 to 147 mg/1000 kcal] cholesterol). During the second
dietary phase, subjects consumed a low-fat diet (15.1% total fat, 5.0%
saturated fat, 17 mg/1000 kJ [73 mg/1000 kcal] cholesterol). During the
baseline and low-fat diet phases, which lasted 5 to 6 weeks each, the
energy intake was adjusted to keep body weight constant. During the
third diet phase (low-fat ad libitum diet) subjects were given the same
low-fat diet for 10 to 12 weeks, but could adjust their intake between
66% and 133% of the energy required to maintain body weight.

MAIN OUTCOME MEASURES--Body weight and plasma lipid levels.

RESULTS--Consumption of the low-fat diet under
weight-maintenance conditions had significant lowering effects on
plasma total cholesterol (TC), LDL-C, and high-density lipoprotein
cholesterol (HDL-C) levels (mean change, -12.5%, -17.1%, and
-22.8%, respectively). This diet significantly increased plasma
triglyceride levels (+47.3%) and the TC/HDL-C ratio (+14.6%). In
contrast, consumption of the low-fat ad libitum diet was accompanied
by significant weight loss (3.63 kg), by a mean decrease in LDL-C
(124.3%), and by mean triglyceride levels and TC/HDL-C ratio that
were not significantly different from values obtained at baseline.

CONCLUSIONS--Our results indicate that a low-fat ad libitum diet
promotes weight loss and LDL-C lowering without adverse effects on
triglycerides or the TC/HDL-C ratio in middle-aged and elderly men
and women with moderate hypercholesterolemia.