Mindful eating: is it alright to eat before bed and how does it affect your body?

We now know that inadequate sleep can influence our food consumption and increase our risk of developing health issues, such as obesity and cardiovascular conditions. But, how much does our food intake influence our sleep?

Little attention has been given to the impact of diet and nutrition on indicators of sleep quality and duration. Emerging evidence indicates that broad, binary labels like ‘healthy foods’ and ‘unhealthy foods’ are unhelpful when considering the complex relationship between food consumption and sleep.

This article will evaluate the scientific evidence on this topic to consider whether consuming certain food groups or specific ingredients in particular patterns can limit or enhance our ability to achieve healthy sleep.

What is the best diet for sleep?

The best diet to adopt for optimal sleep is one that incorporates a wide range of different nutrients without over-indulging in particular macronutrients, such as sugar or fat. Deficiencies in key nutrients have been linked to sleep problems. Although high-carb meals with high glycemic indexes can induce sleepiness, they also impair your sleep quality, increasing night wakings and reducing deep sleep.

Nutritional balance could be achieved by adopting a number of different diets. The Mediterranean diet–plant-based with the inclusion of lean meats and high-fibre ingredients–has been proven to enhance cardiovascular health and sleep quality, with particularly impressive benefits for women.

Researchers also inadvertently found that the DASH diet, aimed at lowering blood pressure by reducing salt and saturated fats in favour of wholefoods with high levels of fibre, potassium and magnesium, tends to result in subjectively better sleep outcomes.

A 2011 study suggested that the protein, carbohydrate and fat content of foods eaten in the evenings negatively impacts sleep architecture. The researchers concluded that ‘nocturnal eating’ (any food intake 30–60 minutes before bedtime) has a negative impact on sleep quality, particularly among women. This effect may be due to the discomfort caused by digestive activity.

A 2016 review reported that a high-carb diet was associated with a shorter period of time falling asleep, less deep sleep and more rapid eye movement (REM) sleep. It was argued that these effects were due to the hormonal processes that are triggered by a high-carb intake, including serotonin regulation, carbohydrate oxidation and reductions in growth hormone secretion.

The same review found that a high-fat diet was associated with reduced sleep efficiency, less REM sleep, more night wakings but more deep sleep. This demonstrates the nuanced interaction between diet and sleep as some food groups appear to enhance sleep in some ways, while hindering it in other ways. Further, it reinforces the need for nutritional balance in the maintenance of good sleep, which is consistent with supporting our general health and wellbeing.

Remember to consult a healthcare professional before making significant changes to your diet.

What is the impact of specific foods on sleep?

Anecdotal evidence and some small studies attest to the connection between consuming specific foods and changes in sleep. Large-scale scientific research on the topic is limited, but it appears that certain foods have the potential to significantly alter sleep.

Foods that may have a strong, positive influence on sleep

Some studies have reported that fruits, such as kiwis and cherries, can positively impact sleep. The high levels of melatonin and antioxidants in kiwis may allow them to promote sleep by regulating the circadian rhythm and protecting against oxidative stress. Tart cherries–rich in antioxidants, serotonin and folate–have also demonstrated positive effects on sleep, although the effects vary depending on the type of cherries used.

A 2019 study reported that soybeans, lima beans, wholegrains and carbohydrates all had a particularly strong association with enhanced sleep quality. The phytoestrogens in soybeans may have regulated sleep duration and sleep quality, while the presence of tryptophan (a precursor to serotonin and melatonin) may have played a role too. L-ornithine could have been responsible for reducing stress and anxiety as other studies have revealed its positive impact on objective and subjective indicators of sleep quality.

The high levels of phosphorus found in lima beans could explain their positive impact on sleep quality as phosphorus plays a key role in cell repair, metabolism and sleep, and low levels are associated with sleep deficit. The presence of magnesium and vitamin B6 could have also contributed to the sleep-enhancing effects of lima beans.

There are many potential explanations for the apparent sleep-promoting effects of wholegrains. The magnesium content could have relaxed muscles while playing a role in melatonin regulation. The butyric acid could have also aided muscle relaxation by helping the body to produce GABA receptors. The contribution of complex carbs could have raised serotonin levels and lowered cortisol (stress) levels, while aiding the delivery of tryptophan to the brain. Selenium could have helped settle restlessness and restore balance within the body to support a restful slumber.

Interestingly, white rice induced a shorter time spent falling asleep than jasmine rice. This was perhaps due to the higher carbohydrate content in white rice, which would have led to increased tryptophan levels. In this instance, the need for further research is clear as this study was based in Pakistan where rice is often consumed alongside curries, and the spiciness of the curries could have undermined the sleep-promoting effects of the rice.

Foods that may have a moderate, positive influence on sleep

Research suggests that dairy products and leafy greens have a moderately strong association with improved sleep.

The calcium in dairy products may help the brain to use the tryptophan in the processing of the sleep hormone, melatonin. Malted milk, with its balance of wheat, malt barley, sugar, milk, vitamin D and vitamin Bs, has been associated with fewer sleep disturbances across different age groups.

There are also indications that nighttime milk–milk that has been expressed from cows during the night–has sleep-promoting effects, probably due to the high levels of tryptophan and melatonin present. The selenium, butanoic acid and serotonin found in milk and cheese has also been linked to better sleep.

Diet and nutrition is not just about food. Herbal teas are popularly used in the treatment of sleep problems due to their relaxing properties. The presence of nutrients such as L-Threonin and apigenin, as well as herbs like rhodiola rosea, can calm the body and mind, promoting the ideal state for a restful slumber.

The jury is still out

Foods such as fatty fish, dark chocolate and processed meat have produced mixed results. Although fatty fish contains nutrients like vitamin D and omega-3 that are important for the regulation of serotonin (and therefore sleep), researchers have linked it to decreased sleep efficiency and no positive effects on sleep quality or duration.

Dark chocolate appears to create both positive and negative effects on sleep as the magnesium content induces sleep while the stimulating impact of the caffeine and theobromine hinder sleep. For this reason, the current official guidance is to avoid chocolate before bedtime.

Foods that may have a negative influence on sleep

Spicy, fatty and sugary foods are best avoided around bedtime. Spicy foods can cause gastro-intestinal issues such as heartburn, indigestion and acid reflux, that often feel even worse when lying down. Spicy foods also increase overall body temperature, which has been linked to poorer sleep quality.

Sugary foods and fatty foods have been shown to decrease orexin cell activity, which may lead to poor and interrupted sleep as orexin is crucial for the regulation of circadian rhythms.

In fact, a lack of orexin is believed to be the primary cause of narcolepsy, a sleep disorder involving extreme levels of daytime sleepiness and “sleep attacks”. More generally, high intakes of fat and sugar have been associated with shorter, lighter and less restorative sleep, as well as more night wakings.

How do patterns of food consumption affect sleep?

Skipping breakfast or eating late at night has long been frowned upon as some studies have linked it to serious health issues, such as obesity and type 2 diabetes. However, new findings suggest that skipping breakfast is not in and of itself responsible for the increased risk of developing these illnesses.

For those who regularly engage in late-night eating, skipping breakfast can effectively prolong the overnight fasting period to help with the management of metabolic abnormalities.

It is important to note that late-night eating can result in poor sleep, as well as circadian misalignment, which substantially impairs the internal clocks that exist in multiple organs. However, for many people late-night eating is simply unavoidable due to work commitments or other reasons.

A 2018 study suggests that late-night eaters make the following adjustments to limit the adverse impacts associated with eating late at night…

• Limit late-night meals to small amount of easily digestible foods with fewer calories
• Either skip breakfast or consume a very low-calorie meals, including water and the minimum minerals and vitamins required to get you through the morning

More research is required to enhance our understanding of how the timing of food consumption contributes to our sleep. This will allow us to make more informed decisions regarding our food consumption patterns.

Overview

• A balanced diet packed full of a wide variety of nutrients, vitamins and minerals is the best way to support healthy sleep, while the over-consumption of macronutrient groups such as fats, sugars or carbohydrates should be avoided;
• Eating around bedtime is not advisable but neither is going to bed hungry, so opt for a small, healthy snack;
• Certain foods have the potential to enhance sleep, so next time you’re feeling peckish at bedtime consider choosing one of these options as opposed to an unhealthy alternative;
• The timing of food intake can have a significant impact on general health and may play a role in sleep problems, although further research is required in this area;
• While late-night eating is problematic, there could be ways of ameliorating the adverse health impacts through making particular changes to dinner and/or the following morning’s breakfast.

Currently, less than 1% of those experiencing sleep problems are treated using functional foods. Further research into the links between diet, nutrition and sleep could encourage greater symbiosis between food and sleep medicine in the future.