Keto specialist website Ketodietapp.com added: “This fast should be followed for no more than three to five days.
“If you follow the fat fast for a longer period, you run the risk of getting your body into starvation mode, losing muscles and getting deficient in essential nutrients.”
The website also warned those who are “keto-adapted”, who have already followed the keto diet for around three or four weeks at least, should try the diet.
Otherwise, the changes to the body might be too uncomfortable to deal with.
It is important to take a multivitamin when doing a fat fast, and to avoid intensive exercise.