Longitudinal Changes in Dietary Fiber Intake Predict Changes in Body Fat in Women

Purpose The purpose of this study was to determine the extent measured changes in total dietary fiber (FIB) per 1000 kcal were predictive of changes in body fat percentage (BF%) in 228 middle-aged women during a 20-month prospective study. Other objectives were to ascertain the extent differences in age, and various baseline measures, including: body fat, body weight, energy intake, fat intake, and physical activity, and changes in various measures, including: energy and fat intake, and physical activity, affected the relationship between changes in FIB and changes in BF%.

Methods The cohort included women who were non-smokers and had SMIs < 30 at baseline. The vast majority of participants were Caucasian, educated, and married. Mean age at baseline was 40 years. Dietary intake, including FIB, was measured using 7-day, weighed food records at baseline and follow-up. Fiber intake was expressed as grams per 1000 kcaL Total body fat was assessed with multiple measures in the Bod Pod and the average was used. Physical activity was measured objectively using CSA accelerometers worn at the hip (or 7 consecutive days at baseline and follow-up.

Results Regression analysis showed that baseline and follow-up fiber intakes were not predictive of changes in body fat. However, change in FIB was a strong predictor of change in BF% over the 20-month study (F = 7.51, p = 0.0066). Specifically, as FIB increased BF% decreased significantly in the women. Although changes in total energy intake and changes in dietary fat had the greatest impact on the FlB-BF% relationship, none of the potential confounding factors caused the association to become non-significant.

Conclusion Apparently, increasing consumption of dietary fiber over a 20-month period promotes the loss of body fat in women, whereas decreasing fiber intake elevates risk of fat gain, independent of age, physical activity level, energy intake, dietary fat intake, and baseline levels of body fat Evidently, fiber intake plays an important role in weight management over time.