An ad libitum, very low-fat diet results in weight loss and changes in nutrient intakes in postmenopausal women.
OBJECTIVE
To determine whether a very low-fat diet (<15% of energy intake) consumed ad libitum during an 8-month period can achieve weight loss of 5% to 10% of initial body weight while still providing adequate intakes of other essential nutrients.


METHODS
Longitudinal, 8-month, ad libitum, free living, very low-fat diet trial.


METHODS
Fifty-four of the sixty-four healthy postmenopausal women recruited completed the entire study (age 59+/-8 years, BMI=29.6+/-6.3). Twenty-four of these women used hormone replacement therapy, thirty women did not.


METHODS
Weekly sessions aimed at teaching and reinforcing a very low-fat intake diet for eight months. MAIN: outcome measures Body weight, percent body fat, waist-to-hip ratio, resting energy expenditure, respiratory quotient, and nutrient intakes derived from 7-day food records at the beginning and at 2, 4, 6, and 8 months of the study. Statistical analysis performed Repeated measures analysis of variance and Tukey post hoc analysis were used to analyze significant differences in mean data (P<.05).


RESULTS
Fat intake decreased from 33.2+/-7.5% to 11+/-4% over the 8-month intervention period (P<.00001). Weight loss was 6.0 kg+/- 4.2 kg (P<.000038), an 8% weight change, and decrease in percent body fat of 2.7%+/-0.2% (P< or =.000046). Weight correlated better with the self-reported fat intake (r=0.321, P<.01) than the energy intake (r=0.263, P<.05) at baseline. Fiber intake increased from 16 g+/-0.6 g to 23 g+/-0.2 g (P<.0005). All micronutrient intakes remained at or above preintervention ranges, except for a decrease in vitamin E intake from 8.1 mg+/-4.0 mg to 3.7 mg+/-1.1 mg (P<.0005) on the very low-fat diet and linoleic acid from 6.3%+/-1.5% to 2.5%+/-0.7% (P<.000001) with no significant reduction in linolenic acid. Hormone replacement was not associated with the amount of weight loss.


CONCLUSIONS
This study demonstrates that adherence to a very low-fat diet consumed ad libitum causes weight loss in the 5% to 10% range and a reduction of body fat. These reductions, along with the observed decreases in fat intake, are associated with improved health outcomes. Because of the decreased vitamin E and n-3 fatty acid intake, emphasis on foods high in these nutrients may need to be encouraged for those consuming a very low-fat diet.
Mueller-Cunningham
Wendy M
WM
Department of Family & Consumers Sciences, California State University, Sacramento, 95819-6053, uSA. wcunningham@csus.edu
Quintana
Roberto
R
Kasim-Karakas
Sidika E
SE
D001823:Body Composition / Q000187:drug effects; D001824:Body Constitution; D015992:Body Mass Index; D018752:Diet, Fat-Restricted / Q000592:standards; D004041:Dietary Fats / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000008:administration & dosage; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D008903:Minerals / Q000008:administration & dosage; D009753:Nutritive Value; D009765:Obesity / Q000178:diet therapy*; D017698:Postmenopause / Q000378:metabolism*; D014815:Vitamins / Q000008:administration & dosage; D015431:Weight Loss
D004041:Dietary Fats; D004043:Dietary Fiber; D008903:Minerals; D014815:Vitamins