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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #208588
Title: Use of cereal fiber to facilitate reduced energy intake in CALERIE, a one year clinical trial of human caloric restriction

Author
item GILHOOLY, CHERYL - TUFTS-HNRCA
item DAS, SAI KRUPA - TUFTS-HNRCA
item GOLDEN, JULIE - FDA
item MCCRORY, MEGAN - BASTYR UNIVERSITY
item ROCHON, JAMES - DUKE CLINICAL RES. INST.
item DELANY, JAMES - UNIV. OF PITTSBURG
item FREED, ALICIA - TUFTS-HNRCA
item FUSS, PAUL - TUFTS-HNRCA
item DALLAL, GERARD - TUFTS-HNRCA
item SALTZMAN, EDWARD - TUFTS-HNRCA
item Roberts, Susan

Submitted to: Aging Clinical Experimental Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2007
Publication Date: 2/10/2008
Citation: Gilhooly, C.H., Das, S., Golden, J.K., Mccrory, M.A., Rochon, J., Delany, J.P., Freed, A.M., Fuss, P.J., Dallal, G.E., Saltzman, E., Roberts, S. 2008. Use of cereal fiber to facilitate reduced energy intake in CALERIE, a one year clinical trial of human caloric restriction. Aging Clinical Experimental Research. 20:513-520.

Interpretive Summary: Problem Statement There is currently substantial interest in human caloric restriction (CR) but the question of how feasible human CR really is remains uncertain. Dietary fiber has the potential to enhance adherence to a CR regimen by acting as a satiety agent but to date conclusions about the role for dietary fiber in sustaining human CR are unclear. We conducted a study testing the feasibility of adding 20 g/day of additional dietary fiber to an already adequate dietary fiber intake and its ability to increase adherence to a human CR regimen of 48 weeks duration. Research accomplishment(s) This investigation included both a 6 week RCT of DRI levels of dietary fiber vs. DRI levels + 20/g day of an insoluble dietary fiber preparation, and an additional 9-month period of voluntary consumption of the same type of fiber. We found no significant effect of dietary fiber intakes >DRI levels on weight change during the short period of the RCT. However, during this 6 week period all food was provided and adherence was high irrespective of the fiber randomization group. In the subsequent 9 month period when fiber intake was voluntary (and for most of this time subjects self-prepared their regimen), those who continued consuming high levels of dietary fiber sustained significantly greater levels of CR, equilibrated at a lower BMI, and experienced greater dietary satisfaction than subjects who ate less dietary fiber. Although the fiber results during the self-selected phase of the study need further support by RCTs, they are consistent with the suggestion that dietary fiber has small but cumulative effects on energy balance that promote greater weight loss over time and that high fiber cereal preparations can be used to facilitate a human CR regimen. Research contribution This study was part of the NIA-funded CALERIE trials and we believe is an important and exciting addition to the growing human caloric restriction literature. To our knowledge, there is no published research on the use of large amounts of cereal fiber (greater than DRIs) to support caloric restriction regimens.

Technical Abstract: Background: Caloric restriction (CR) attenuates biological aging in animal models, but little is known about factors that may facilitate adherence to CR regimens in humans. We examined the effects of insoluble cereal fiber on ability to sustain CR over 1 year. Methods: In 34 healthy overweight volunteers (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 20g/d of dietary fiber from a high fiber cereal (+F) or not to 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 satisfaction with the amount of consumed food. Results: During 5-10 weeks of CR, 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, adherence was lower and there was a significant association between total fiber intake and %CR (r= 0.69, p<0.001), decreased BMI (r=-0.38, p=0.04) and satisfaction with the amount of consumed food (r=0.59, p=0.002). Conclusions: A high fiber cereal may facilitate CR in humans; longer-term intervention studies are needed to confirm these findings.