Intermittent fasting usually means time-restricted eating: confining food to a window, like 8 hours a day. Some people find it a simple way to eat fewer calories, and short-term studies show modest weight loss. But several controlled trials that matched calories between fasting and regular eating found similar results — suggesting much of the benefit comes from eating less overall, not the timing itself.
It can still be a useful tool if the structure helps you, and some research suggests benefits for blood sugar when the eating window is earlier in the day. But it's not magic, it's not for everyone (people with a history of disordered eating, or who are pregnant, should be cautious), and what you eat still matters more than when.