Finally, if you fast for several days

 

Finally, if you fast for several days, you may drop pounds but most of it will be water and some of it may be muscle, which will make you look thin and flabby, rather than tight and toned. Fasting for longer periods can also slow down your metabolism, making it harder to keep the weight off or to lose weight later.
We're not going to tell you that eating lots of veggies and fiber and drinking lots of water is a bad idea. But you also need to make sure you're getting all of the nutrients you need, including protein from lean meats, eggs, beans, or peas and calcium from low-fat or fat-free milk or yogurt. You definitely shouldn't start a detox diet or stop eating from any major food group without talking to your doctor or a registered dietitian.
Your body is designed to purify itself. Your liver and kidneys will do the job they're supposed to do if you eat a healthy diet that includes fiber, fruits, veggies, and plenty of water. If you're feeling tired or run down, or if you're concerned that you're overweight, talk with a doctor who can help you determine the cause and recommend ways to address the problem.