Why is it important for long-term health and well-being that weight reduction diets not mimic starvation?

Answer 1

During starvation, the body's priority is to supply the nervous system and red blood cells with sufficient glucose. Once glycogen stores have been depleted within the first 24-36 hours of no food intake, glucose must be synthesized from noncarbohydrate substances via gluconeogenesis. Muscles contribute to gluconeogenesis by supplying amino acids, lactate, and glycerol, all of which are used by the liver to generate small amounts of glucose. The loss of lean tissue during the early stages of acute starvation reduces the body's total energy requirements. The body goes into "survival mode" by dramatically reducing its metabolically active lean tissue. This defensive action is important because it helps prolong survival if starvation continues. In this way, less energy is needed to maintain lean body mass, thus decreasing the body's overall energy needs. Similarly, self-imposed energy restriction, as with some eating disorders and very low-calorie diets, also sacrifices lean tissue to support gluconeogenesis. Successful weight-loss diets advocate slow and gradual weight loss to minimize the loss of lean tissue and thus muscle mass and strength.