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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #166847
Title: DIETARY FIBER AND FAT ARE ASSOCIATED WITH EXCESS WEIGHT IN YOUNG AND MIDDLE-AGED U.S. ADULTS

Author
item HOWARTH, NANCY - TUFTS-HNRCA
item HUANG, TERRY - TUFTS-HNRCA
item ROBERTS, SUSAN - TUFTS-HNRCA
item MCCRORY, MEGAN - TUFTS-HNRCA

Submitted to: Journal Of The American Dietetic Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2004
Publication Date: 9/1/2005
Citation: Howarth, N.C., Huang, T.T., Roberts, S.B., McCrory, M.A. 2005. Dietary fiber and fat are associated with excess weight in young and middle-aged U.S. adults. Journal Of The American Dietetic Association. 105(9):1365-1372.

Interpretive Summary: The purpose of this study was to examine the relative associations of dietary factors, specifically fiber, energy density, and macronutrients, with BMI, using U.S. national survey data. We hypothesized that high fiber intake is associated with a low BMI, independent of macronutrients and energy density, and that a high fiber, low fat diet is more strongly associated with low BMI than is either a high fiber or low fat diet alone. Our analysis was limited to young and middle aged adults because of the age-related decrease in BMI after ~60 y. Our results combined with those of previous intervention studies strongly suggest that in women a high fiber diet appears to be more effective than a low fat diet for preventing weight gain, and the combination of high fiber and low fat may be even more effective than either one alone. Fiber intakes were extremely low in our study, with only about 5% of individuals consumed in the AI or above, suggesting a possible fiber deficiency in the US population. However, given that in women, associations between fiber intake and BMI were seen even at low levels, and the known benefit of fiber in the prevention of several chronic diseases, increased fiber consumption should be more widely promoted.

Technical Abstract: To examine relative associations of dietary composition variables with BMI among young and middle-aged U.S. adults. We hypothesized that in subjects with physiologically plausible reported energy intakes (rEI), fiber intake is inversely associated with BMI, independent of other dietary composition and socio-demographic variables. Data from adults aged 20-59 y in the Continuing Survey of Food Intakes by Individuals (CSFII) 1994-6 were used. Exclusions were pregnancy or lactation, food insecurity, missing weight or height data, and having only 1 dietary recall. Based on our previously published methods, a physiologically plausible rEI was calculated as being within +/-22% of predicted energy requirements (pER) for the average of two 24-h recalls. Reporting plausibility (rEI/pER*100%) averaged 83% in the total sample (n=4539) and increased to 96% in the plausible sample (n=1932). Only ~5% of the plausible sample consumed the Adequate Intake for fiber. In plausibly reporting women, fiber, its interaction with percent energy from fat, and energy density were independently associated with BMI. Only percent energy from fat was associated with BMI in men reporting plausibly. Compared to the total sample, stronger relationships between diet and BMI were observed among the plausible reporters. In women, a low fiber(<1.5 g/MJ), high fat (35% energy) diet was associated with the greatest increase risk of overweight or obesity compared to a high fiber, low fat diet. Weight control advise for U.S. women should place greater emphasis on consumption of fiber.