low fat diets can be unhealthy

Doug Skrecky (oberon@vcn.bc.ca)
Sat, 15 May 1999 11:28:21 -0700 (PDT)

Citations: 1-2

Wells AS. Read NW. Laugharne JD. Ahluwalia NS. Institution
Centre for Human Nutrition, University of Sheffield, Northern General Hospital, UK. a.s.wells@sheffield.ac.uk Title
Alterations in mood after changing to a low-fat diet.
British Journal of Nutrition. 79(1):23-30, 1998 Jan. Abstract
The effects on mood of reducing dietary fat while keeping the energy constant were examined in ten male and ten female healthy volunteers aged between 20 and 37 years. Each volunteer consumed a diet containing 41% energy as fat for 1 month. For the second month half of the subjects changed to a low-fat diet (25% energy
from fat) and the remainder continued to eat the diet containing 41% energy from fat.
Changes in mood and blood lipid concentrations were assessed before, during and at the end of the study. Profile of mood states (POMS) ratings of anger-hostility significantly increased in the intervention group after 1 month on the low-fat diet,
while during the same period there was a slight decline in anger-hostility in the control subjects (group F 6.72; df 1.14; P = 0.021). Tension-anxiety ratings declined in the control group consuming the higher fat diet but did not change in the group consuming the low-fat diet
(group F 6.34; df 1.14; P = 0.025). There was a decline in fasting concentrations of HDL-cholesterol after the low-fat diet and a small
increase in subjects consuming the medium-fat diet (group F 4.96; df 1.12; P = 0.046), but no significant changes in concentrations of total serum cholesterol, LDL-cholesterol or triacylglycerol were observed. The results suggest that a change in dietary fat content from 41 to 25% energy may have adverse effects on mood. The alterations in mood appear to be unrelated to changes in fasting plasma cholesterol concentrations.


Morgan SA. O'Dea K. Sinclair AJ.
Department of Medicine at St Vincent's Hospital, Fitzroy, Victoria, Australia.
A low-fat diet
supplemented with monounsaturated fat results in less HDL-C lowering than a
diet [see comments].
Comment in: J Am Diet Assoc 1997 Aug;97(8):840 Source
Journal of the American Dietetic Association. 97(2):151-6, 1997 Feb.
OBJECTIVE: The purpose of this study was to compare the effects of a very-low-fat
diet with a low-fat
diet supplemented with monounsaturated oil on plasma lipid levels in subjects with hypercholesterolemia. DESIGN: The 8-week study was divided into one 2-week baseline diet and two 3-week intervention periods in a randomized crossover design. SETTING: The study was conducted in an outpatient setting at the Deakin Institute of Human Nutrition, Deakin University, Geelong, Australia. SUBJECTS: Twenty-four free-living subjects with hypercholesterolemia participated in and completed the study. INTERVENTION: After a 2-week baseline period of a self-selected diet, subjects were assigned to one of two dietary interventions: a
very-low-fat (10% of
energy from fat), high-carbohydrate diet or a low-fat (26% of energy from
fat) diet supplemented with olive oil and an olive oil-based margarine. MAIN OUTCOME MEASURES: Lipid measurements included total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride concentrations. Plasma cholesteryl esters were measured to monitor compliance. STATISTICAL ANALYSES: A paired t test was used to assess differences between treatment periods for each subject. The dependence of the difference between treatment periods on the covariates of age, sex, initial cholesterol concentration, and energy intake was analyzed using repeated measures and analysis of covariance. RESULTS: The low-fat diet supplemented
with monounsaturated fat resulted in significantly less high-density lipoprotein cholesterol lowering than the very-low-fat
diet (P=.005). Both interventions resulted in significant reductions in both low-density lipoprotein cholesterol and total cholesterol compared with the baseline diet. APPLICATIONS: This study suggests that a low-fat diet enriched with
olive oil provides advantages over a
diet in the control of serum lipoproteins among persons with hypercholesterolemia.