Late night eating and sleep - what's the connection?

How to get to sleep quicker: does eating dinner later really make it harder to drift off?

Posted by for Nutrition

The old saying goes: “Breakfast like a king, lunch like a prince, dine like a pauper.” But given how busy we are these days, most of us dine like kings and spend our days pecking on snacks. Is that why we’re all so bloody tired?

If you’re looking to sleep better, there are a few obvious things to avoid. Scrolling on your phone for hours in bed, watching the 10pm news, having a massive row (online or in person) just before lights out – all of these things are going to make switching off harder. And while we can cut the caffeine by 3pm and try to avoid social media close to bedtime, the one thing that’s a lot harder to control is the time we eat our last meal.

During the lockdowns, it was easy to be fed and in bed by 10pm. But now we’re back in the office, meeting up with pals, going to the gym or doing other after-work activities, dinner is a far less structured affair. After two years of finishing supper by 7.30pm – earlier than I ate it while at school – I’m now back to cooking at 8.45pm on Tuesdays, 9pm on Thursdays and midnight on weekends. 

As a vegan, however, I tend to tell myself that it could be worse; plants can be digested pretty swiftly if you chew them properly and because my mornings often start with fasted cardio, I’m putting all that late-night fuel to good use. I see it as a kind of daily carb-load situation for my morning runs – only having breakfast if I’m running over 10k at the weekend. 

Despite my own dodgy anecdotal evidence, however, eating earlier has long been touted as being the healthier option, particularly when it comes to sleep quality.

Is eating earlier really healthier?

Studies have found that those of us who experience stress tend to have a spike in ghrelin (the hunger hormone) in the evening. The more ghrelin you produce, the more awake you’re likely to feel because your circadian rhythm gets disrupted. That means if you’re feeling more intense hunger, you’re probably more likely to eat past the point of satiety, which could lead to or exacerbate bloating, discomfort and acid reflux in bed. In fact, if you do have a reflux issue, you’re supposed to avoid eating at least three hours before lying down. 

So, does that mean those of us who eat late are risking our health by not grabbing a quick evening snack on the way home from work? Or is there more to this than simply sticking by strict timings?

“We know from a body of research called chrono-nutrition that the time that we eat can have a big impact on our health outcomes and our ability to digest and absorb food,” says Sophie Medlin, consultant dietitian and founder of City Dietitians

“We all have different chronotypes, meaning that if you’re a morning person, you respond differently to people who are ‘night owls’. There is some excellent data to show that people who habitually eat most of their food at night – shift workers – have worse health outcomes than those who eat during the day, even if they eat the same foods. 

“This is because after around 9pm, we are in our biological night and we are less efficient at breaking down fats and sugars and storing them so they don’t cause further problems. 

How you eat impacts your overall body clock

“We also know that if you eat too late – after our biological night – that we can’t digest the food so easily and it can sit in our bowel for longer, leading to more fermentation and issues like bloating. It can, of course, also affect our sleep because our body is unable to fully switch off while it has significant digestion to perform.”

But Medlin says that the kind of diet you have also has an impact. Eating higher fat or higher carbohydrate foods at night are likely to cause more harm, she says, while higher fibre foods can be more difficult to digest so may keep us awake for longer.

If you do need to eat late, she recommends going for a higher protein meal to keep you full without spiking the blood glucose or causing much bloating.

“The general advice is more about eating two-to-three hours before bed to allow time for the food to move down from the stomach, which means you’re less likely to experience disturbed sleep from feeling too full or ‘heavy’ in your stomach,” explains nutritionist Kimberley Neve. When asked if vegans like me might be better off than omnivores when it comes to eating late, she says that while, in theory, meat takes a little longer to digest, there’s not enough research to suggest either way.

Of course, our eating habits and sleep are highly individual. Signe Svanfeldt, nutritionist at Lifesum, says: “Some people need to have a couple of hours between their last meal and bedtime, while others need to have a snack just before bed to fall asleep properly.” But it’s not just a biological thing; she goes on to say that our schedules have a massive impact on how late we eat. If you work out in the evening, for example, “you’ll probably need a late-night snack afterwards”. If you work out in the morning, however, you might need an early morning snack and a bigger breakfast afterwards. In other words, there’s no one size that fits all.

Svanfeldt does stress that alcohol and caffeine are known to impact sleep quality, and that eating heavy meals before bed can interfere with sleep quality.

When we talk about sugar, however, we’re on more solidly scientific ground. “If you eat sugar right before bed, you’re likely to have sleep disturbances as the energy will be released quickly. A diet that is generally low in sugar will help to regulate energy levels throughout the day, which will also help with better sleep, but it wouldn’t be the first/most obvious ‘cure’ for bad sleepers,” Neve says.

Communities in southern Europe eat later – does that mean the Mediterranean diet isn’t so healthy?

Other pieces of research claim that eating late at night can push our blood glucose and cholesterol levels higher, while a study published in the International Journal Of Cancer looked at the impact of late-night eating on people in Spain. It found that eating at least two hours before bed cuts your risk of breast cancer by 18%. 

That’s interesting, given that countries like Spain, Italy and Greece are famed for both super-late dinner times and health-boosting Mediterranean diets. We’re forever hearing how the eating habits in these countries are linked to extended life spans, lower risks of heart disease and better gut health. But in Spain, you’d be hard pushed to find a family or restaurant serving dinner before 9pm.

When asked if, given the extensive health benefits of eating like the Italians, Mediterranean countries really do have their timings wrong, Neve says that she’s just not sure. “Many [people in those countries] may also go to bed a little later and there are lots who don’t actually eat as late as we think, so I’m afraid it’s not clear. That said, the general custom is to eat a much lighter meal in the evening, which is quicker and easier to digest, and a larger meal at lunch, so that could play a role too. In the UK, we generally eat quite big meals in the evening.” Even with that in mind, it’s interesting that heavy lunches are often followed by siestas – which again, means lying down soon after consuming food.

Medlin offers another explanation for the difference between us and the southern Europeans: “Eating later and our tolerance for this is largely genetically determined. Sometimes when we think about the way other cultures eat, we take one factor and extrapolate it out of context. 

“For example, ‘People in Mediterranean countries eat late and they’re healthy so I can’. This doesn’t take into account things like the fact that people take a siesta which changes their biological night, the largely plant-based diet (where traditional diets are still followed) and the amount of energy as a percentage that is consumed earlier in the day, which remains high in traditional Mediterranean cultures.”

Does eating later give us more energy the next morning?

OK, so we can’t just assume that because someone in Tuscany tends to have supper at 9pm, we too should be aiming to have our bowls of pasta late at night. But if we do dine later than most, what impact might that have on our ability to work out the next morning?

Neve says she doesn’t believe that delaying dinner by an hour or two would make much difference to glycogen stores the following day. The main difference, in her opinion, would be how well or badly you sleep. “That extra hour may just mean that you don’t sell as well, which would have a detrimental effect.”

Nutritionist Rohini Bajekal agrees that changing your meal times to factor in fasted cardio really isn’t the way to go. “I’m not a fan of fasted workouts for women, given the increase in cortisol, and always recommend having something light such as a banana with peanut butter or even a slice of wholemeal toast with hummus prior to a workout.” And that’s because, she points out, “almost all of the research on fasted workouts has been done on men or animals such as male rodents”. 

How to eat for a better sleep

“With regards to meal timings, research suggests that consistency is best,” Bajekal explains. She recommends trying to have set meal times daily with a hearty breakfast soon after waking, a good-sized lunch and a smaller dinner.

She points to research which has shown that eating larger breakfasts and lunches is more beneficial to optimise insulin sensitivity than a greater number of meals and snacks throughout the day. “In other words: breakfast like a king, lunch like a prince and dinner like a pauper. This helps nurture your circadian rhythms and regulate your internal body clock. Aim to have your last meal by 7pm in the evening if possible, to allow for a gentle overnight fast or, in other words, leave around 12 hours between dinner and breakfast.”

And if you can’t eat by 7pm, try not to stress. Use this information to enjoy your lunches more and avoid skipping breakfast. If you can’t finish eating earlier in the day, leaving 12 hours between your last and first meal may be more doable. After all, if you’re dining at 9pm, that means having your bowl of cereal as you read through your morning emails at 9am, which isn’t so bad.

For more nutrition tips, check out the Strong Women Training Club.

Images: Getty

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Miranda Larbi

Miranda Larbi is the editor of Strong Women and Strong Women Training Club. A qualified personal trainer and vegan runner, she can usually be found training for the next marathon, seeking out vegan treats or cycling across London on a pond-green Tokyo bike.