How long should you fast if trying to lose weight and do you eat anything?

AnswerFasting does work, depending on how much fat your body has and how long. Fat is used to store unused calories and use them at disposal when food is not present. If you are 20 pounds overweight then 4-7 days will do it. Remember, younger people tend to lose weight faster and easier then older people, also losing weight is more difficult for females then men. Women over the age of 40 lose their ability to burn fat which is why you see most older people fattier then young ones.