Achieving weight loss
An energy deficit of 2250-4500 kJ from daily energy expenditure will allow for a 0.5-1 kg weight loss per week. This can be achieved both through decreasing energy intake and/or increasing energy expenditure. However, although weight loss can be achieved in the short-term, an issue of major importance is how to sustain this weight loss long-term.
A meta-analysis assessing long-term weight maintenance reported approximately 15 per cent of subjects undergoing weight loss interventions maintain either their reduced weight or an overall reduction of 9-11 kg at a follow-up time of up to 14 years. Weight loss maintenance is defined as maintaining a reduction of 10 per cent of initial body weight for one year. A weight loss strategy must therefore be sustainable in the long-term for successful maintenance of a reduced weight.
Proven methods for the Management of Overweight and Obesity in Adults notes that the success of a weight loss strategy will be further increased with incorporation of additional principles including regular physical activity, behavioural management strategies, social support and attention to psychological adjustment including behaviour modification and stress management strategies
Incorporating moderate sustainable physical activity is highly effective and will improve both weight loss and weight maintenance. A recent Cochrane review showed that exercise combined with diet substantially increased the weight loss achieved than with diet alone. This can include both structured exercise (at least 30 minutes per day) and incidental exercise (daily lifestyle activities such as climbing stairs whenever possible, walking greater distances (e.g. parking further away, walking during lunchtime, walking down the hall instead of emailing), gardening and house cleaning). Current public health recommendations are for 200-300 minutes per week of moderate exercise for long-term weight loss maintenance and prevention of weight regain in overweight and obese adults.
There is also evidence that physical activity, even in the absence of weight loss, improves a range of metabolic risk factors such as hypertension, insulin resistance and impaired glucose tolerance. Mechanistically, immediately after an acute period of exercise, glucose transport in skeletal muscle is increased through insulin-independent translocation of the GLUT4 glucose transporters to the cell membrane. The molecular mechanisms for enhanced insulin sensitivity with exercise training may be related to increased expression/activation of key proteins in the insulin signalling pathway that regulate glucose metabolism in skeletal muscle.