Use of cereal fiber to facilitate adherence to a human caloric restriction program

Caloric restriction {(CR)} attenuates biological aging in animal models but there is little information on the feasibility and efficacy of {CR} regimens in humans. We examined the effects of consuming an insoluble cereal fiber supplement on ability to sustain {CR} over 1 year in healthy overweight adults.

In 34 healthy overweight women and men {(BMI} 25-30 kg/m2, age 20-42 yr), a 30% {CR} regimen meeting national recommendations for dietary fiber was provided for 24 weeks, and for an additional 24 weeks subjects were counseled to prepare the same regimen at home. During 5-10 weeks of {CR,} subjects were randomized to consume an extra 20 g/day of dietary fiber from a high fiber cereal {(+F)} or to not consume additional fiber {(-F).} After this time, all subjects were encouraged to consume the extra fiber. Outcomes included adherence to the provided and self-prepared {CR} regimens (energy intake determined using doubly labeled water), changes in body weight, and self-reported satisfaction with the amount of consumed food.

During 5-10 weeks of {CR} when all food was provided, both {+F} and {-F} groups were highly adherent to the {CR} regimen and there was no significant difference between groups in energy intake (p=0.51), weight change (p=0.96), or satisfaction with amount of provided food (p=0.08). During self-prepared {CR} from 25 to 48 weeks, mean adherence was lower than during the food-provided phase and there was a significant association between fiber intake and % {CR} (r=0.69, p<0.001), decreased {BMI} (r=- 0.38