During a fast, the body produces few new proteins and requires cells to take protein from nonessential sources, break them down and use the amino acids to make new proteins, vital for survival. Then, after eating, new proteins are formed in the brain and elsewhere.

It can take 10 to 12 hours to use up calories in the liver before your body changes over to use the stored fat.

After meals, glucose is used for energy, while fat is stored in fat tissue. During fasts, once glucose is depleted, stored fat is broken down and used for energy.

Many people will experience hunger, irritability, and a reduced ability to concentrate. These symptoms seldom last for more than a month.

Some people may binge-eat when they finally can eat, creating an eating disorder. Others may consume all food regardless of its nutrition...

To lose weight, strive for sixteen calorie-free hours. Stop eating by 8 pm, and eat again at noon the next day. Results can take up to four weeks to notice.

Intermittent dieters should eat healthy foods, including whole grains and healthy fats and protein. They sh...