Does the Method of Weight Loss Effect Long-Term Changes in Weight, Body Composition or Chronic Disease Risk Factors in Overweight or Obese Adults? A Systematic Review

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.

Obesity Energetics: Body Weight Regulation and the Effects of Diet Composition

“…15 However, exercise results in preferential loss of body fat and maintenance of fat-free mass compared with diet-induced weight loss. 16,17 but exercise does not appear to prevent the slowing of metabolic rate during weight loss. 18 Exercise interventions typically result in less average weight loss than expected, based on the exercise calories expended, and individual weight changes are highly variable even when exercise is supervised to ensure adherence.…”

Randomized trial comparing effects of weight loss by liraglutide with lifestyle modification in non‐alcoholic fatty liver disease

“…Weight loss and maintenance are currently the mainstays of long‐term management of NAFLD . However, weight maintenance is challenging, with weight regain of ~55% at 4‐18 months in clinical trials . Gastrointestinal adverse effects, plateau of weight loss, daily injections and cost limit the duration of GLP‐1 agonist usage, with 30%‐40% of outpatients stopping treatment before 1 year .…”

Voxel‐based morphometry reveals brain gray matter volume changes in successful dieters

“…We are aware of the positive impact that increases in exercise and fitness can have on brain structure and function . However, typical weight management programs, the present investigation included, combine both diet and exercise in order to promote WL . Accordingly, we were unable to distinguish the influence of changes in exercise as compared with changes in diet on brain structure.…”