New Insights into The Biggest Loser Contestants’ Weight Loss and Metabolic Rate
The Biggest Loser, a popular reality TV show that aired on NBC for over a decade beginning in 2004, featured participants with obesity competing to see who could lose the highest percentage of body weight through intense physical challenges and a reduced-calorie diet. Studies on the show's contestants revealed that significant weight loss led to a drastic slowing of metabolism, and regaining lost weight did not restore metabolism back to pre-weight loss levels. Consequently, individuals who lost a significant amount of weight had to maintain an extremely low-calorie intake to avoid regaining the lost weight.
A more recent study by Dr. Kevin Hall, who previously studied The Biggest Loser Contestants, delves into the metabolic changes that take place after significant weight loss. Dr. Hall posits that contestants' sustained periods of intense physical activity resulted in a reduction in metabolism, which minimized changes in total energy expenditure to maintain energy balance. Interestingly, the degree of metabolism reduction at the end of the competition was not related to subsequent weight regain, and those who maintained the most weight loss had the greatest amount of metabolism adaptation. This indicates that metabolic adaptation is a response to lifestyle changes, namely the significant increase in physical activity observed in those who maintained the most weight loss. While compensatory mechanisms do not fully counteract lifestyle changes, they do occur, meaning it is possible to keep off substantial amounts of weight.
Overall, the studies on The Biggest Loser contestants suggest that short-term reductions in resting metabolic rate are due to extreme calorie restriction during active weight loss, whereas persistent metabolic adaptation later is related to substantial, sustained increases in physical activity. Physical activity is a critical component of successful weight maintenance, according to the National Weight Control Registry, but the exact relationship between body composition, physical activity, energy regulation, and weight maintenance requires additional research. In the meantime, it is advisable to consume healthy whole foods in moderation, avoid processed foods, and engage in regular physical activity to maintain healthy body weight.