Exercise for Weight Management

Physical activity and exercise are important for people with chronic disease who have overweight or obesity for several reasons. These include:

• Increase energy expenditure to assist with weight loss and particularly with weight maintenance following a weight loss program²
• Attenuate some of the negative consequences of weight loss on lean muscle mass, bone and aerobic function
• Provide overall health benefits including for other common co-morbidities

Role of physical activity in the management of obesity

Evidence-based guidelines for obesity management and weight loss recommend that interventions for weight loss incorporate physical activity and exercise.^{28, 29} There is obviously a strong rationale for all individuals, irrespective of body mass status, to engage in the recommended levels of physical activity and reduce sedentary behaviour. Indeed, prolonged sitting time is associated with an increased risk of premature death as well as multiple chronic health problems.^{30, 31} However, it should be remembered that physical activity and exercise alone is unlikely to result in significant weight loss unless it is combined with dietary change.^{32, 33} This is widely acknowledged due to the small contribution of physical activity levels to overall energy output (20-30%).¹ HOWEVER, increasing physical activity has a range of health benefits EVEN IF NO WEIGHT IS LOST.^{32, 34} In individuals who are overweight or obese, aerobic exercise improves blood pressure,³⁵ cholesterol,³⁶ and glucose levels,³⁷ all relevant for management of the Edmonton Stages of Obesity.

Exercise is also important to attenuate some of the negative consequences of weight loss on lean muscle mass,³⁸ bone and aerobic function.³⁹ As well as affecting fat tissue, the catabolic state induced by caloric restriction also causes catabolism of other tissue types including skeletal muscle, heart, liver and kidney.⁴⁰ The lean muscle mass lost during dietary restriction⁴¹ reduces muscle strength.⁴² For this reason, strengthening exercise is recommended particularly for older individuals who already experience age-related sarcopenia and for those undertaking a very low calorie diet.