Intermittent fasting has become an increasingly popular approach to weight management and metabolic health. But is when you eat more important than what and how much you eat?

What is intermittent fasting?
Intermittent fasting describes eating patterns that alternate between periods of eating and fasting. Rather than prescribing specific foods, it primarily changes when you eat.
A common approach is time-restricted eating — limiting food intake to a set window each day, such as 8–10 hours.
Does intermittent fasting help with weight loss?
Yes, it can — but it doesn't appear to be meaningfully better than traditional approaches.
A 2025 systematic review and network meta-analysis of 99 randomised clinical trials involving 6,582 adults found that both intermittent fasting approaches and a continuous energy restriction approach reduced body weight compared with eating without intentional energy restriction (1).
However, when intermittent fasting was compared with traditional continuous energy restriction, the differences were generally small. In other words, intermittent fasting can work, but it does not appear to be a uniquely superior method of losing weight.
Why might intermittent fasting work?
One reason intermittent fasting may lead to weight loss is relatively simple: reducing the amount of time available for eating may help some people consume less energy overall.
For example, a shorter eating window may reduce evening snacking or other discretionary eating, helping to create an energy deficit over time.
For some people, following a time-based rule may also feel simpler than counting calories or monitoring portions.
However, fasting does not remove the importance of overall diet quality and energy intake. Regardless of when you eat, prioritise a balanced dietary pattern prioritising whole foods such as vegetables and fruit, wholegrains, legumes, adequate protein, nuts, seeds and healthy unsaturated fats.
Is intermittent fasting right for everyone?
Not necessarily.
Some people find intermittent fasting simple and sustainable, while others experience hunger, low energy or difficulty fitting restricted eating windows around work, exercise, family meals and social occasions.
It may also be inappropriate for some people, including those taking certain glucose-lowering medications or with a history of disordered eating. Individual medical and nutritional advice may be required before commencing a fasting regimen.
Take-home message
Intermittent fasting can be an effective tool for weight management, but it isn't necessarily better than other approaches.
The most effective dietary strategy is one that supports good nutrition, helps you achieve your health goals and, importantly, is realistic and sustainable over the long term.
References
- Semnani-Azad Z, Khan TA, Chiavaroli L, et al. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. BMJ. 2025;389. doi: 10.1136/bmj-2024-082007.
