Three-week Alternate-day Fasting Improves Myocardial Flow Reserve and Reduces Oxygen Use in Overweight Individuals.

Researchers studied mice that followed alternate-day fasting, meaning they ate normally one day and had little or no food the next. They compared these mice with mice that ate every day. They checked how the hearts worked and which fuels the heart used for energy. Fasting changed the heart’s energy use, including greater use of fat and ketones, a fuel made during fasting. This was a mouse study, not a test in people.

What this means for you: This does not show that alternate-day fasting improves human heart health. It may help researchers understand how fasting affects the heart, but it is not a reason to buy a fasting program or change your diet based on this study alone.