Increased Physical Activity Associated with Less Weight Regain Six Years After "The Biggest Loser" Competition.

OBJECTIVE: The aim of this study was to explore how physical activity (PA) and energy intake (EI) changes were related to weight loss and regain following "The Biggest Loser" competition. METHODS: At baseline, week 6 and week 30 of the competition, and 6 years after the competition, body composition was measured via dual-energy x-ray absorptiometry, resting energy expenditure was measured by using indirect calorimetry, and EI and PA were measured by using doubly labeled water. RESULTS: Six years after the competition, median weight loss in 14 of "The Biggest Loser" participants was 13%, with those maintaining a greater weight loss (mean ± SE) of 24.9% ± 3.8% having increased PA by 160% ± 23%, compared with a PA increase of 34% ± 25% (P = 0.0033) in the weight regainers who were 1.1% ± 4.0% heavier than the precompetition baseline. EI changes were similar between weight loss maintainers and regainers (-8.7% ± 5.6% vs. -7.4% ± 2.7%, respectively; P = 0.83). Weight regain was inversely associated with absolute changes in PA (r = -0.82; P = 0.0003) but not with changes in EI (r = -0.15; P = 0.61). EI and PA changes explained 93% of the individual weight loss variability at 6 years. CONCLUSIONS: Consistent with previous reports, large and persistent increases in PA may be required for long-term maintenance of lost weight.

Persistent metabolic adaptation 6 years after "The Biggest Loser" competition.

OBJECTIVE: To measure long-term changes in resting metabolic rate (RMR) and body composition in participants of "The Biggest Loser" competition. METHODS: Body composition was measured by dual energy X-ray absorptiometry, and RMR was determined by indirect calorimetry at baseline, at the end of the 30-week competition and 6 years later. Metabolic adaptation was defined as the residual RMR after adjusting for changes in body composition and age. RESULTS: Of the 16 "Biggest Loser" competitors originally investigated, 14 participated in this follow-up study. Weight loss at the end of the competition was (mean ± SD) 58.3 ± 24.9 kg (P < 0.0001), and RMR decreased by 610 ± 483 kcal/day (P = 0.0004). After 6 years, 41.0 ± 31.3 kg of the lost weight was regained (P = 0.0002), while RMR was 704 ± 427 kcal/day below baseline (P < 0.0001) and metabolic adaptation was -499 ± 207 kcal/day (P < 0.0001). Weight regain was not significantly correlated with metabolic adaptation at the competition's end (r = -0.1, P = 0.75), but those subjects maintaining greater weight loss at 6 years also experienced greater concurrent metabolic slowing (r = 0.59, P = 0.025). CONCLUSIONS: Metabolic adaptation persists over time and is likely a proportional, but incomplete, response to contemporaneous efforts to reduce body weight.