Studies in humans have shown promising health benefits with some intermittent fasting regimes.

• People can't stick to eating every other day. If you do alternate-day fasting or skip breakfast every day, it's associated with negatives and very hard to do. Instead, people who want to benefit from intermittent fasting should be less extreme, such as 12-hour eating windows.
• In the handful of studies that tested alternate-day fasts with people, more than a third dropped out, and in those who stayed, there wasn't much advantage in weight loss or heart health.

It's easy to research the diets of mice when they are in a controlled environment. However, human studies are more complicated as they need to be in a controlled environment with controlled diets.

Instead, studies track what people eat from what they report. But people underestimate their calorie intake and overestimate the energy they spend, misrepresenting what they ate.