The relationship between obesity and the gut microbiome has become increasingly recognized, highlighting the need to determine how specific diets can beneficially impact gut microbiota to improve metabolic disease. Many studies have found an increase in dietary fiber not only causes a shift in the microbiome but also results in weight loss and altered feeding behavior. Dietary fibers are diverse both in composition and source, being found in many different plant-based flours. Fiber can also be characterized by solubility, with highly soluble fibers being most easily broken down by gut bacteria to produce short chain fatty acids (SCFAs). However, the efficacy and mechanism of specific plant-based flours on obesity is not well characterized. To better understand which plant-based flours have the greatest impact on energy homeostasis, we treated high-fat diet (HFD; 45% kcal from diet)-fed rats with four different flours for 6wks. The flours, barley flour, oat bran, wheat bran, and amylose maize were incorporated into the HFD at either 5% or 10% fiber content, and were compared to an isocaloric, nutrient-matched chow and HFD controls. We hypothesized that the soluble barley flour at 10% fiber would have the greatest impact on energy homeostasis due to the high levels of beta-glucan, while the amylose maize, oat bran, and wheat bran will have a significant but less pronounced effect. We found that the rats fed high dose barley flour and wheat bran had significantly reduced body weight gain. High and low dose barley flour resulted in significantly reduced food intake compared to HFD, and all high dose flour diet-fed rats exhibited lower adiposity compared to the HFD rats. We found all high dose flour diet-fed rats exhibited changes in feeding behavior and energy expenditure compared to HFD rats measured by metabolic cages. These results demonstrate plant based fibers can have differing effects on food intake and body composition, underscoring the need to determine the most effective dietary manipulations for obesity treatment.
T. Martinez: None. F. Duca: None. S.N. Weninger: None. R. Meyer: None. A.I.L. Lane: None.
National Institute of Food and Agriculture (2019-67017-29252)