If you must have a late-night snack, unsalted pistachios are an excellent option. They are rich in nutrients, protein and fibre, and can benefit heart health by lowering cholesterol and blood pressure. A new study has even found that eating them before bed positively alters gut bacteria in people with prediabetes. They’ve also been shown to encourage the growth of beneficial intestinal microbiota – the “good” microbes in our gut – especially those that produce short-chain fatty acids, leading to favourable health effects.
“Pistachios are packed with fibre and they contain other bioactive compounds that really help our ‘good’ gut bacteria to thrive, encouraging it to become more abundant,” says Charlotte Radcliffe, a registered nutritionist. “Portion size is the key, though: you really should eat no more than a handful.”
The only downside to pistachios, it seems, is that it’s easy to accidentally eat too many – something Stansbie warns is potentially harmful. “These days a lot of people think they’re squirrels, not humans,” she says. “Eating three walnuts or a handful of almonds or pistachios is fine, but they shouldn’t be your morning, afternoon and evening snack. You must also remember that they’re very calorie-dense. People who are careful to monitor the calories in their meals forget that even a small pack of nuts may contain 500 calories, which is a lot.”
Avoid eating a large, late dinner
Research increasingly shows that eating a heavy meal late at night has a negative effect on our gut microbiome and a range of other bodily processes. It can also result in acid reflux, poor-quality sleep and weight gain.
“The optimum time to eat your evening meal is two to three hours before going to bed,” advises Stansbie. “This allows time for the meal to be digested and the body to prepare itself for sleep mode.”
Stansbie emphasises the importance of setting a routine and, as far as possible, sticking to it. A consistent eating pattern nourishes the colonies of beneficial microorganisms that live in our gut, helping them thrive, whereas irregular schedules disrupt this balance. “The body is regulated by circadian rhythms,” she says. “If it expects food around 7pm, it prepares by releasing hunger signals, stomach acid and digestive enzymes. Eating at irregular times can delay digestion and cause indigestion.”
Radcliffe adds that acid reflux is another common issue linked with late-night eating. “When you lie down too soon after a meal,” she explains, “the stomach contents press against the lower oesophagus. The valve that normally keeps acid in place can then leak, causing heartburn. This not only disrupts sleep but also prevents the body from carrying out its vital night-time healing.”
“For good gut health, choose light meals with lean proteins that supply B vitamins to support the liver, plus plenty of fibre to nourish the gut microbiome,” says Stansbie. “Wholegrain carbohydrates are also great – they provide steady energy and prevent sugar spikes that may disturb sleep. You should definitely avoid heavy, high-fat foods at night, as it takes a long time to digest, which means all our energy is concentrated on the stomach, not leaving enough resources for the body to regenerate during the night.”
Sleep on your left side
“For anyone who suffers with acid reflux, sleeping position can make a big difference,” says Radcliffe. Our stomach is positioned slightly to the left of our bodies, and sleeping on our left side can help food move through the digestive tract.
Studies have shown that lying on your left side can reduce reflux symptoms. This is because it positions the stomach lower than the oesophagus, so it basically makes it harder for the acid to flow upwards, back into the oesophagus. And if you sleep on your back, the reverse is true, which can make reflux worse.”
Stansbie cautions, however, against trying too hard to sleep on your left if it doesn’t come naturally: “Having a good night’s sleep is more important than being fixated or sleeping in a certain position.”
Go to sleep at the same time each night (and try to wake up at a similar time each morning)
A study carried out by researchers from King’s College London and Zoe, the science and nutrition company, claims that disrupted sleep patterns are linked to changes in your gut microbiome. Researchers found that just a 90-minute difference in the timing of the midpoint of sleep – the halfway point between sleep time and wake-up time – is associated with differences in gut bacterial species.
This can partly be put down to the fact that so-called “social jet lag” is associated with lower overall diet quality, higher intakes of sugar-sweetened beverages and lower intakes of fruits and nuts, which may directly influence the abundance of specific microbiota in your gut. Doing shift work, for example, can lead to dietary cravings at random times of the day, making following a healthy diet harder to achieve. Nonetheless, it seems that the microbes in our gut microbiome are affected by the time of day we eat and sleep in ways that we do not yet fully understand.
What we do know for sure is that disruption to our body’s natural circadian rhythms can lead to digestive discomfort, an imbalance in gut microbiota, and an increased risk of issues like acid reflux, bloating and long-term health problems such as obesity and metabolic disorders.
“Our bodies are prepared to do certain things at certain times,” says Stansbie, “so routine really has an impact. Erratic sleeping and waking patterns can send our body into confusion and result in too long or too short fasting windows: at times our digestive system is overwhelmed, at others, starved. It’s not a problem if you occasionally have a lie-in on a Saturday – that’s not going to make a huge difference. But a good eating and sleeping routine improves appetite, digestion and overall health.”
Steer clear of high-fat snacks and alcohol
One of the most harmful aspects of late-night eating is the effect it has on our blood-sugar levels. High-fat snack foods (such as crisps and chocolate), in particular, tend to be disruptive to our metabolism and cause insulin resistance, which can lead to diabetes and weight gain (especially as they’re designed to be easy to consume and we often eat them while watching TV). One study also found that a high-fat diet can decrease the diversity of good bacteria in our guts.
“I would always recommend something light and easy to digest, like bananas, oat cakes, rice cakes or a small handful of nuts and seeds,” says Radcliffe. “High-fat foods should be avoided. Of all the nutrients, fat is the hardest one to for the body to digest, so it’s going to take that much longer to process.”
Drinking even a small amount of alcohol, meanwhile, may initially make you feel sleepy, but in most cases it will impair sleep quality by interfering with natural sleep stages. Alcohol also negatively impacts your gut bacteria, triggering irritation and inflammation, impacting nutrient absorption and digestion, and driving up the risk of gut-related health problems such as ulcers and gastritis.
“The best evening beverage choice is water, plain or flavoured naturally with fruit,” says Stansbie. “A small cup of herbal or sleep tea before bed may also help, though not in large quantities as you may need to get up and go to the bathroom during the night.”
Take a magnesium supplement
Emerging research suggests that magnesium plays a role in maintaining a healthy gut microbiome and also acts as a useful sleep aid. “Ideally you should take magnesium glycinate, which can help relax the nervous system,” says Stansbie. “But be aware that other kinds of magnesium, like magnesium citrate, are mainly used as a laxative, and that could cause digestive system upset, either during the night or in the morning.”
Radcliffe also strikes a note of caution. “While supplements can offer some benefits to people who are deficient in magnesium, the evidence is rather mixed. Most people can get enough magnesium from consuming a healthy, balanced diet [it is found in foods such as leafy greens, beans, nuts and seeds]. My advice is that, yes, if you’re deficient, magnesium supplements do have a place, but be mindful that high doses of magnesium can cause some quite unpleasant side effects, so it’s best to speak to a healthcare professional before considering supplementation.”
