Question special

If the calorie consumption was significantly higher before trial enrollment, are we concerned that on trial completion, participants could return to baseline calorie consumption, or at least close? I am thinking about extrapolating the results to our real world, clinical setting. If my patient is consuming 2300 calories and I tell her to reduce her intake to 1500 but maintain the same level of physical activity (or more because many people who start a 'diet' also start exercising at the same time), chances are she will feel deprived and cranky and resort to what she was doing pre-trial, soon after the study ends.