Browse evidence-based analysis of health-related claims and assertions
Skipping meals on a regular schedule, without cutting calories, seems to shrink belly fat and improve blood‑sugar markers more than just eating fewer calories.
For older adults, going without food on certain days (but eating the same total calories) might help lose body fat and lower inflammation faster than just eating fewer calories every day — at least at first — but that doesn’t always mean better long-term health.
Skipping meals or eating fewer calories can lower a hormone called IGF‑1 in healthy people, and doing a special three‑month diet three times does the same, which might help lower cancer risk.
Cutting calories might help overweight women after menopause remember things better and boost brain areas tied to thinking, according to a 4-month diet study.
People tend to stick with intermittent fasting better than regular calorie counting over the long term, with fewer dropping out of studies, suggesting it might be easier to keep up with.
Going without food on certain days works just as well as eating fewer calories every day to help your body respond better to insulin, especially if you're overweight or have early signs of diabetes.
Both skipping meals now and then (intermittent fasting) and eating fewer calories can help overweight adults lose weight and body fat over several months, according to several studies.
Intermittent fasting might help lower blood sugar a little more than regular calorie cutting in people with extra weight, but the difference is so small it probably doesn’t matter in real life.
Intermittent fasting might help lower triglycerides a little more than regular calorie cutting in people with overweight or obesity, but the difference is so small that scientists can't say for sure it's not just due to chance.
If you're trying to improve your cholesterol and have extra weight, going on an intermittent fasting diet works about as well as cutting calories every day — both help in similar ways.
Intermittent fasting might help people lose a little more weight than cutting calories the usual way, but the difference is so small it could just be due to chance — overall, both methods work about the same for weight loss in people with overweight or obesity.
Intermittent fasting might help people with extra weight lose a little more body mass than cutting calories regularly, but the difference is small and we’re not sure if it really matters for health.
For people who are overweight or obese, cutting calories all the time works about the same as intermittent fasting when it comes to cholesterol, triglycerides, and belly fat — neither one has a clear edge.
If you're trying to lose weight and are overweight or obese, cutting calories just two days a week doesn’t work much better than cutting them every day — the difference is pretty small.
A stricter form of intermittent fasting where you eat very little every other day leads to more weight loss than cutting calories daily, but we only have early evidence from a couple of small studies.
For adults who are overweight or obese, cutting calories all the time works about the same as fasting on and off when it comes to losing weight — both help lower BMI just as much in the short to medium term.
People who try intermittent fasting tend to lose a little more weight than those who just cut calories continuously, according to several studies.
Eating only on certain days or within a short daily window might help people with extra weight lose more body fat than eating the same number of calories every day, but we only have a couple of studies to back this up.
Some people think that skipping meals on certain days (like the 4:3 or 5:2 plans) could help the body use insulin better than just eating fewer calories every day, but we only have a couple of small studies to back that up.
If you're an adult with extra weight, cutting calories by either fasting some days or eating less every day leads to similar weight loss and health improvements — neither method works much better than the other if you eat the same total amount of food.
It looks like the weight‑loss you get from intermittent fasting starts to slip back after about three months, but steady calorie‑cutting keeps the loss steady, so fasting might not work as well over the long run.
Eating a bit less consistently can lead to noticeable weight loss over a short period for people who are overweight or obese.
If you do alternate-day fasting, you’ll likely lose about 5 kilograms in the short term if you’re an adult with overweight or obesity.
Cutting calories a lot all the time helps people with extra weight lose the most pounds quickly — about 11.5 kilos on average in the short term.