What time should you stop eating?

Victoria Taylor, Senior Dietitian at the BHF, says:

There are several theories about why timing of meals is important. Studies have shown that even when people eat the same number of calories, the time of day they are eaten affects how they are used in the body.

This difference could affect weight, cholesterol levels and blood sugar levels – all of which can affect your risk of heart and circulatory diseases.

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Why does it matter when you eat? 

What’s causing this isn’t completely understood. It could be that the body uses up more energy digesting food in the early part of the day. But other theories focus on differences in how the body uses energy across the day. Some look at the idea that skipping breakfast or eating late at night may disrupt your internal body clocks, or how your meal timing can affect your behaviour later in the day.

There is evidence from studies looking at the meal patterns of large groups of people (observational studies) that skipping breakfast is linked to an increased risk of obesity, as well as higher “bad” cholesterol levels and worse cardiovascular health.

However, studies where people were put into groups to either eat or skip breakfast (randomised controlled trials) have given more mixed results. These randomised controlled trials have generally been small in size and short in duration, so more research is needed.

But some findings suggest that advice to eat breakfast has a limited benefit for weight loss, although it could be helpful in regulating blood sugar levels and making it easier to eat healthily later in the day. It’s possible that having breakfast could also help you feel that you have the energy to be more active across the day.

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When is the best time to eat dinner?

There is also some evidence that eating late at night can be linked to obesity as well as having effects on how the body regulates blood sugar levels.

Research is limited, but there appears to be a link between our internal body clock and the digestion and absorption of nutrients.

Our body’s circadian rhythms (its natural daily cycle) are designed for eating in the day and sleeping at night. If they are disrupted, this could have implications for our heart health.

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What time should you stop eating?

In the UK, we typically eat across a 14-hour period from our first mouthful to our last. That means a 10-hour gap overnight.

A smaller overnight gap has been linked to weight gain and effects on blood sugar levels. And having a longer overnight gap seems to have benefits, including reductions in blood pressure and weight. This is called time-restricted eating (TRE). This aims to limit eating hours to the daytime, which fits better with our circadian rhythm, and to avoid eating at night.

There is a lot of interest in time-restricted eating, as it’s a simple strategy that doesn’t focus on what you eat, or how much. But at the moment, results from the research vary too much to draw firm conclusions. There is some evidence that it helps with short-term weight loss, but we don’t know what happens in the long term.

We also don’t know how long the ideal ‘eating window’ should be. At the moment, studies use anything from four to 13 hours per day. It’s also not clear how time-restricted eating could help lower the risk of heart and circulatory diseases, as most of the research has focused on obesity.

There are also questions about how well time-restricted eating works in real life, rather than in a more controlled research experiment. The practicalities can be challenging – for example, if you’re invited to a social event that involves food, but doesn’t fit into your eating window.

Achieving a healthy balanced diet is more important than when you eat

We don’t know whether trying to eat your last meal of the day earlier could lead to a greater use of convenience food or eating on the go. We also don’t know whether fitting eating hours into a smaller window could lead people to be less active during the day, or whether normal exercise sessions could feel more challenging if they happen during fasting times.

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What does this mean for us?

It’s too soon to know for sure how meal timing influences our health and how we can realistically translate this into our eating patterns. More research is being carried out, and in the future we could see timing of meals included in dietary guidelines. For now, focusing on what you eat and achieving a healthy balanced diet is more important than when you eat.

What we can say is that trying to stick to a regular meal pattern, and eating earlier in the day rather than late at night, is unlikely to be harmful and could help our health.

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