Energy balance and energy expenditure in obesity: Is obesity a disease of inactivity?

The aim of this clinical review was to examine the problem of obesity in the context of energy balance, and specifically to examine the role of increased physical activity in altering energy balance in obese individuals. The control of obesity depends on a regulatory axis involving feedback control between: food intake, nutrient turnover, energy expenditure, and body fat stores. Physical activity impacts on this regulatory axis at all levels. There are four major conclusions regarding physical activity in the management of obesity: (/) a combination of physical activity and restriction of energy intake is more effective for weight loss than exercise or dieting, independently; (/'/) physical activity may help to offset the loss of fat-free mass and attenuate the decline in metabolic rate that occurs with food energy restriction while dieting; (Hi) exercise may be most beneficial for the prevention of weight regain after weight loss; and (/V) the impact of physical activity on body composition and body weight occurs in a dose-dependent manner. There is consensus that moderate intensity activity of approximately 45 - 60 min/day is required to prevent the transition to overweight or obesity. However, in order to lower the overall risk of chronic diseases of lifestyle, minimising co-morbidities of obesity and increasing adherence, the Centers for Disease Control and American College of Sports Medicine guidelines provide an evidence-based recommendation that 'every adult should accumulate 30 minutes or more of moderate-intensity physical activity on most, preferably, all days of the week'