Effects of a cereal rich in soluble fiber on body composition and dietary compliance during consumption of a hypocaloric diet

Objectives: To investigate the effects of oars, a cereal rich in soluble fi ber, on body composition changes and dietary compliance during consumption of a weight loss diet. Methods: Subjects were 41 healthy men and women aged 18 to 78 years. Weight maintenance energy requirements were established over two weeks during. co nsumption of a control diet with low soluble fiber content. Subjects then c onsumed a hypocaloric diet for six weeks, either consuming a low soluble fi ber control diet or a diet containing 45 g/1000 kcal rolled oats, a whole g rain cereal rich in soluble fiber (mean energy deficit -895 +/- 18 kcal/day relative to weight maintenance energy requirements). Changes in body fat a nd fat-free mass were determined by underwater weighing. and dietary compli ance was assessed using the urinary osmolar excretion rate technique, in a final phase of the study, subjects ate ad libitum for six months, and chang es in body weight and composition were monitored. Results: There was no significant effect of the oat-containing diet on body weight or composition changes during the hypocaloric regimen or in the sub sequent ad libitum period. In addition, fecal energy excretion was not sign ificantly different between groups. However, there were non-significant tre nds indicating reduced hunger in the oat group compared to controls (freque ncy of hunger 2.5+/-0.5 vs. 3.6+/-0.4, P=0.1). In addition, fewer oat subje cts were non-compliant (four versus seven subjects dropped out or had urina ry osmolar excretions greater than 130% of values predicted from dietary in take), but again the difference was not significant. Conclusions: These results suggest that use of a cereal rich in soluble fib er in a closely monitored hypocaloric feeding regimen does not improve weig ht loss or dietary compliance. Further studies are needed to examine the po ssibility that cereals containing soluble fiber may have effects on hunger and dietary compliance that could be important in less tightly controlled p rotocols than the one described here.