The Effects of Dietary Fat Intake on Resting Energy Expenditure and Body Composition PDF Download

Author: Nichole Mi Hui Eytcheson
Publisher:
ISBN:
Category :
Languages : en
Pages : 92

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Book Description
Whether changing from a high-fat diet to an isoenergetic, low-fat, high- complex-carbohydrate diet results in thermogenic benefits is controversial. Brief dietary interventions and failure to account for the potential influence of body-fat distribution on energy metabolism could have confounded the interpretation of previous studies. The success of individuals who lose weight by changing from high fat diets to low-fat diets has prompted numerous, well-controlled studies of this phenomenon. The literature regarding a thermogenic effect of low-fat, high-CHO diets reveals conflicting evidence. The present study was designed to answer the following questions; 1) Does dietary fat restriction increase the caloric need to maintain weight? 2) Does lowering the fat intake in the diet affect resting energy expenditure (REE)? 3) Does dietary fat restriction affect body composition? Methods Sixty-four healthy post menopausal women were recruited to the study and enrolled in four cohorts of 16 participants every 4 months. Each cohort went under 3 dietary interventions over a 4 month period. Dietary intervention involved a 4-month long eucaloric controlled-feeding that was designed to reduce the fat intake stepwise to 15% of the daily energy intake. Bioelectrical impedance (BIA) was used to assess body composition and provide values for FFM and FM. REE was collected using indirect calorimetry and calculated using the Weir equation. Data were expressed as means + standard deviations (SD). Results The four dietary interventions did not alter REE (p=.979). There was a trend for an increased respiratory exchange ratio with the low-fat diet (p=.067). Although the controlled-feeding phase was designed by calculated, computer generated analysis to deliver 35%, 25% and 15% of the energy intakes from fat, laboratory and chemical analysis of the diet showed that the actual dietary fat intakes were 31%, 23% and 14% respectively. There was a significant difference in body weight (0.9 kg) between baseline and after the 35% fat diet (p=0.0003), no significant change between the 35% and 25% fat diet (0.05 kg, p=0.218), and no significant change between the 25% fat diet and the 15% fat diet (0.05 kg, p=0.156). During the eucaloric feeding as dietary fat decreased from 31 % to 23% to 14 %, the energy cost of weight maintenance increased from 8724+1281 kJ, to 8946+ 1310 kJ, and to 9122+ 1365 kJ, respectively. These increases were significant (+223+400 kJ, p