What to eat and drink while intermittent fasting

Intermittent fasting is one of the most popular dietary trends of the moment. With fewer rules than other nutrition plans and a simple structure, it’s easy to see why it might appeal. Whether you follow the 5:2 plan or prefer 16:8, the idea is to eat normally followed by a period of fasting (not eating). Simple, right?

In short, intermittent fasting involves only eating during certain windows of time. You fast during certain hours and then eat normally for the rest of the time. There’s not one official way to fast, but some popular methods include:

OK, you can’t eat... but surely you can drink? The answer is yes, as long as you stick to calorie-free drinks. To be clear, we’re talking about intermittent fasting here – not fasting for medical, religious or other reasons. Different fasts have different rules, but the general consensus is that you can drink non-alcoholic and low- or no-calorie drinks like black tea alongside water. This is because they're unlikely to trigger a significant metabolic or insulin response. Sparkling water, cucumber water and lemon water are generally considered fine, as are small amounts of low-calorie bone broth.

Intermittent fasting isn’t routinely recommended by organisations such as the NHS as a preferred approach for weight management, although some healthcare organisations recognise it as one possible dietary strategy for certain people. According to the British Heart Foundation, it’s likely more sustainable to focus on eating a balanced diet every day, such as the Mediterranean diet which focuses on foods like olive oil, legumes and plant foods alongside healthy fats and balanced meals.^1,3

“A balanced approach works best,” explains Madalena. “Try to include sources of protein to support muscle maintenance and satiety (fullness) and fibre-rich carbohydrates to support more gradual digestion and satiety.¹ If you’re breaking your fast in the morning, a yoghurt bowl with toppings like nuts, seeds and fruit provides a good mix of that. For something savoury, a meal like salmon with wholegrain rice and some veg is ideal.

“As the eating window is shorter, some people may struggle to meet their nutritional needs. If the routine doesn’t fit your schedule or feels stressful, it’s unlikely to work long term. And if something doesn’t feel right, it’s worth discussing with a healthcare professional," says Madalena. Stop or seek professional advice if you experience:

“Intermittent fasting may not be appropriate for everyone. If you have certain medical conditions, take medications that require food or are undergoing treatment, it’s important to speak with a healthcare professional before starting,” says Madalena. You also shouldn’t follow an intermittent fasting diet if:¹

Evidence is still mixed when it comes to intermittent fasting but it’s generally considered safe for most healthy people to try.¹ The priority is a healthy, balanced diet with plenty of fruit, vegetables, whole grains and sources of healthy fat and lean protein. So, if intermittent fasting works for you, that’s great – but if not, a Mediterranean-style dietary pattern (or one that you can stick to and is healthy) is probably the more evidence-based and sustainable approach.

Disclaimer – This article provides informational advice and is not a substitute for medical care. Working with experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.