I always think of it as the difference between starving in a cave waiting for winter to end and starving while attempting to hunt down food in the summer. In th

I always think of it as the difference between starving in a cave waiting for winter to end and starving while attempting to hunt down food in the summer. In the winter, reducing energy expenditure is important so you lose muscle first. In the summer it's more important to maintain condition so you can fight off competition and cultivate food sources. By hunkering down on the couch and just losing weight you get the winter scenario. By exercising while you lose weight you get the summer scenario.