your body will still be able to metab… and insulin, but will not be able to raise AMPK, since that senses the energy status of the cells. If you are eat a very high fat diet (ketogenic) your body will still be able to metabolize this to energy — generating ATP and lowering AMPK. Only 2 of the 3 nutrient sensing pathways have been alerted. Only complete restriction of nutrients will have this effect (ie. fasting).
…n our body stop growing. Importantly, the same genes that control quiescence also control lifespan. In rodents, fasting for 24 hours every other day or twice weekly extends lifespan up to 30%. Chronic caloric restriction may also have similar benefits. Fasting may promote mitochondrial function, trigger autophagy and DNA repair pathways.