Remind your body often that it is helpless and mortal (burn in a sauna, freeze in an ice bath, get crushed by a heavy load, have a hard time jogging, be exposed to a little radiation, be a little breathless, be exposed to some germs, etc.), spend the night sleeping, just in the day You can eat one meal, drink water, but sometimes stay dehydrated, consume less protein, and make sure that the food you eat consists of low-density vegetable foods. these are Harvard Professor David A. From Sinclair's book "Life, and why we grow old when we don't need it".