Intermittent fasting: pros, cons, and who it isn't for

Our nutritionist · September 27, 2026

A plate of food and a clock — the intermittent fasting pattern

Intermittent fasting remains one of the most talked-about topics in nutrition. Here is what research actually supports and when this approach isn't a good idea.

Intermittent fasting isn't a diet in the usual sense — it's a way of organizing when you eat. It comes with both solid data and some exaggerated promises.

What research supports

Limiting your eating window can help some people reduce overall calorie intake simply by eating less often. Some studies note a positive effect on certain metabolic markers.

Possible risks

Overeating during the allowed window, which cancels out the benefit of restriction.
Irritability and reduced concentration in some people during the adjustment period.
Not suitable for people with a history of eating disorders.

Who should be cautious

Pregnant and breastfeeding women, and people with diabetes or chronic conditions, should only discuss this eating pattern with a doctor — sudden dietary changes can affect medication and overall wellbeing.

For smart snacking, see "Snacks for energy", and for sugar, "Sugar and energy".

Questions and answers

What is intermittent fasting?

It's an eating pattern where meals are limited to a certain time window, for example 8 hours a day, rather than a list of specific foods.

Who shouldn't try intermittent fasting?

Pregnant and breastfeeding women, people with a history of eating disorders, diabetes and several other conditions — only after consulting a doctor.

Does intermittent fasting help you lose weight better than other diets?

Studies show the weight-loss effect is comparable to ordinary calorie restriction — no special advantage for fasting itself has been confirmed.