Obesity is a major risk factor for type 2 diabetes and other chronic diseases. While losing excess weight is known to reduce the risk of such diseases losing weight by non-surgical interventions tends to result in poor weight maintenance. Compensatory responses to energy restriction and weight loss inhibit a continued weight loss and promote regain. These compensations include an increase in appetite and reductions in non-exercise physical activity and resting energy expenditure (REE).

It is intuitive that the amount of energy restriction is proportional to the compensatory responses.  However, little is known about the impact of the severity of energy restriction on the strength of responses. This study has been designed to compare the strength of the compensatory responses in obese postmenopausal women, aged 45-65 years, body mass index 30-40 kg/m². One hundred volunteers will be randomised to either a severe energy restricted diet (60-70% energy restriction) for 4 months followed by a weight maintenance diet or a moderate energy restricted diet (20-30% energy restriction) for up to 12-months. Subjective ratings of appetite before and after a standard meal, physical activity measured via accelerometery, and REE determined by indirect calorimetry, will be measured at baseline, 1-week, 1-month, 4-months and 6-months after the start of the dietary interventions. Participants will be followed-up at 12-months to see whether initial compensatory responses return to normal post intervention.

Given that the increases in appetite and reductions in energy expenditure that occur due to energy restriction predict subsequent weight regain, the results from this study will inform the relative likelihood of weight regain in response to severe versus moderate energy restriction.

This study is a component of the TEMPO Diet Trial (Type of Energy Manipulation for Promoting optimum metabolic health and body composition in Obesity), funded by an NHMRC Project Grant (APP1026005). Trial ID: ACTRN12612000651886.