American Journal of Clinical Nutrition, Vol. 71, No. 3, 706-712, March 2000
C 2000 American Society for Clinical Nutrition

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Original Research Communications

Changes in plasma lipids and other cardiovascular risk factors during 3
energy-restricted diets differing in total fat and fatty acid
composition1,2,3
Manny Noakes and Peter M Clifton
1 From CSIRO Health Science and Nutrition, Adelaide, Australia.


Background: The well-established relation between changes in dietary fatty
acids and plasma lipids has been determined in energy-balance states.
Whether this relation is altered in states of energy restriction and active
weight loss is not clear.

Objective: The objective of this 12-wk study was to compare the time course
of lipid changes and other cardiovascular risk factors in 3
energy-restricted diets (all 6500 kJ) with different total fat and fatty
acid compositions.

Design: Sixty-two subjects with a body mass index (in kg/m2) >24 were
stratified into 1 of 3 parallel dietary intervention groups: 1) a
very-low-fat (VLF) diet (10% of energy from fat; 3% from saturated fat), 2)
a high-saturated-fat (HSF) diet (32% of energy from fat; 17% from saturated
fat), and 3) a high-unsaturated-fat (HUF) diet (32% of energy from fat; 6%
from saturated fat).

Results: After 12 wk, LDL cholesterol decreased by 0.66 ? 0.11 ( ? SEM) and
0.68 ? 0.12 mmol/L (20%) with the VLF and HUF diets, respectively, compared
with a decrease of only 0.24 ? 0.11 mmol/L (7%) with the HSF diet (P < 0.02
between groups). Diet affected the time course of changes in HDL cholesterol
with both high-fat diets, resulting in smaller reductions in HDL cholesterol
at weeks 1 (P = 0.0004) and 4 (P = 0.02); however, these differences were no
longer apparent by 12 wk. Overall weight loss was 8.6 ? 0.4 kg (9.7%) and
waist circumference decreased by 7.3 ? 5 cm (8%) for the combined groups,
with no significant differences between diets.

Conclusions: Significantly greater decreases in LDL cholesterol during
active weight loss are achieved with diets low in saturated fatty acids.
Changes in HDL cholesterol between diets appear dependent on both the fat
content of the diet and the duration of energy restriction.


Key Words: Weight loss . lipids . energy-restricted diet . fatty acids .
diet composition . energy restriction . very-low-fat diet . cardiovascular
risk factors . humans