Abstract
BackgroundDifferences in biological changes from weight loss by energy restriction and/or exercise may be associated with differences in long-term weight loss/regain.ObjectiveTo assess the effect of weight loss method on long-term changes in weight, body composition and chronic disease risk factors.Data SourcesPubMed and Embase were searched (January 1990-October 2013) for studies with data on the effect of energy restriction, exercise (aerobic and resistance) on long-term weight loss. Twenty articles were included in this review.Study Eligibility CriteriaPrimary source, peer reviewed randomized trials published in English with an active weight loss period of >6 months, or active weight loss with a follow-up period of any duration, conducted in overweight or obese adults were included.Study Appraisal and Synthesis MethodsConsiderable heterogeneity across trials existed for important study parameters, therefore a meta-analysis was considered inappropriate. Results were synthesized and grouped by comparisons (e.g. diet vs. aerobic exercise, diet vs. diet + aerobic exercise etc.) and study design (long-term or weight loss/follow-up).ResultsForty percent of trials reported significantly greater long-term weight loss with diet compared with aerobic exercise, while results for differences in weight regain were inconclusive. Diet+aerobic exercise resulted in significantly greater weight loss than diet alone in 50% of trials. However, weight regain (∼55% of loss) was similar in diet and diet+aerobic exercise groups. Fat-free mass tended to be preserved when interventions included exercise.
Highlights
An energy restricted diet, aerobic exercise, and diet combined with aerobic exercise, have shown success in producing clinically significant ($5%) [1] reductions in body weight [2,3,4,5,6,7]
Forty percent of trials reported significantly greater long-term weight loss with diet compared with aerobic exercise, while results for differences in weight regain were inconclusive
It has been hypothesized that the type and magnitude of biological changes predisposing to weight regain may differ between weight loss induced by diet compared with aerobic exercise [16] which may explain the observation of Pavlou
Summary
Aerobic exercise, and diet combined with aerobic exercise, have shown success in producing clinically significant ($5%) [1] reductions in body weight [2,3,4,5,6,7]. Several excellent reviews have described the compensatory changes in biological systems involved in energy utilization/storage and appetite regulation induced by an energy restricted diet [17,18,19,20,21]. These changes act in concert to predispose individuals to regain lost weight. Weight loss by diet results in decreased resting and non-resting energy expenditure [22,23,24], fat oxidation [25], thyroid hormones [26,27,28] and increased cortisol [29,30]; changes which all are associated with increased energy storage. Differences in biological changes from weight loss by energy restriction and/or exercise may be associated with differences in long-term weight loss/regain
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