Effect of Dietary Fiber on the Metabolizable Energy of Human Diets

Abstract

Two diets consisting of natural foods that differed in fiber content were fed to 12 men for 6 wk each in a crossover design. Diet 1 contained 37 g total dietary fiber (TDF) from fruits and vegetables and diet 2 contained 16 g TDF from fruit and vegetable juices in a 2800-kcal menu. Seven-day food, urine and fecal composites were made and analyzed for their gross energy, fat, protein and carbohydrate content during the fourth and fifth weeks of each dietary consumption period. The metabolizable energy (ME) of these diets was determined (gross energy of the diet - gross energy of urine and feces) and calculated by Atwater's general energy conversion factors (4, 9, 4), by specific energy conversion factors used in a U.S. food table and by formulas derived by various researchers. The coefficients of availability of energy and the energy-containing nutrients, fat, protein and carbohydrate, were lower while subjects were consuming the higher fiber diet. The specific energy conversion factors of the U.S. food table gave better estimates of the true ME of the lower fiber diet than the higher fiber diet, overestimating the ME of these diets by only 6% (diet 1) and 4.6% (diet 2).

A diet rich in oat bran improves blood lipids and hemostatic factors, and reduces apparent energy digestibility in young healthy volunteers

“…This is thought to be mediated via a suppression of hunger and food intake, as well as a reduction in apparent nutrient digestibility (Astrup et al, 2010). In our study, we observed an B3% reduction in apparent energy digestibility with the addition of 102 g/10 MJ oat bran to a low-fiber diet, which has been observed before using similar doses of oat bran (Calloway and Kretsch, 1978;Chen et al, 1998), as well as other types of soluble dietary fibers, such as wholegrain rye (Wisker et al, 1996), a fiber mixture from grains, cereals and citrus (Rigaud et al, 1987), and a diet with mixed cereal fibers (Miles et al, 1988). It has been estimated that the gradual weight gain of 0.5-1 kg/year in American adults can be explained by a positive energy balance of o200 kJ/day in most people (Hill, 2006), implying a potential for increased consumption of oat products in body weight management as part of a 'small changes strategy' aimed at reducing positive energy balance.…”

Effects of food form on appetite and energy intake in lean and obese young adults

“…Each of these attributes has been associated with weaker effects on appetite and dietary compensation. [52][53][54][55][56][57][58][59] The absolute and relative importance of these properties, and others, has not been established, but warrant exploration. In summary, the present trial supports an independent effect of food rheology on energy intake.…”

Beverages and positive energy balance: the menace is the medium

“…66 Higher fiber levels in foods can also result in energy loss. 67,68 Thus, it is biologically plausible that energy-yielding beverages will exert weaker appetitive and compensatory dietary responses than solid foods and thereby lead to positive energy balance and weight gain. Professor Anderson poses five key questions in his analysis that provide a logical format for delving further into the issue of beverages and obesity.…”