It is well recognized that weight loss interventions should include a weight maintenance phase after weight loss, to help stabilize weight and teach participants how to keep weight off. Better weight loss outcomes may be achieved by also incorporating a deliberate weight maintenance phase before weight loss. Women who underwent an 8-week weight maintenance phase before a 20-week weight loss phase regained significantly less weight than women who undertook the traditional approach of weight loss before weight maintenance (1). Another appropriate time to incorporate a deliberate weight maintenance phase may be during the weight loss phase. Energy restriction in overweight or obese humans induces a series of physiological effects – notably increased appetite, reduced physical activity and energy expenditure, as well as neuroendocrine perturbations – which can collectively act to hinder further weight loss and fat loss and promote regain, while simultaneously promoting loss of lean tissues. However, certain aspects of the adaptive response to moderate or even severe energy restriction may be normalised or significantly attenuated in overweight and obese people by a period of weight maintenance, but only if the intervention involves complete relief from energy deficit, and particularly if it incorporates physical activity. This would suggest that deliberate periods of energy balance during a weight loss phase could attenuate or deactivate various adaptive responses to energy restriction and thereby increase the efficiency of weight loss. This research has important implications for the optimal design of weight loss regimes involving intermittent energy restriction.