A March 2022 study by the University of Illinois Chicago looked at
(1) Alternate-day fasting — consuming 0-500 calories on alternating feast days;
(2) The 5:2 diet — two fast days and five feast days per week;
and
(3) Time-restricted eating — eating only during a prescribed time window each day.
The study said,
“The main myth is people are going to feel weak and not be able to concentrate during fasting. We’ve shown it is the opposite: They actually have a better ability to concentrate,”
“With any diet, as you lose weight, your metabolism, like your calorie needs, will go down because they’re correlated tightly with your muscle mass. As you lose weight, people tend to lose a little bit of muscle. But fasting doesn’t tank your metabolism at all. We’ve shown that it is the same that would happen with like traditional dieting,”