Why Your Diet Could Be Affecting Your Sleep
As we lie awake at night with a million thoughts running round in our heads, it’s easy to blame our busy minds for stopping us sleeping. On the surface that might be the case, but of course many things influence how we sleep from the natural such as daylight – to what time we switched off our screens that evening. In truth, there is still much mystery surrounding the science of good sleep and the brain, but one of the most interesting areas of research at the moment is how the gut biome (the vast community of bacteria, fungi and yeasts which populate our digestive tract) could be a big influencer on quality and quantity of shut eye.
We already know that the gut biome affects the hormones which control our appetite, and now a recent study by scientists at University of Colorado suggests that prebiotics (a particular type of fibre which encourages the growth of good bacteria in the gut) can promote Non Rapid Eye Movement (NREM) sleep, which is restful and restorative as well as helping to increase Rapid Eye Movement (REM) sleep after being exposed to a stressor. While the researchers say more studies are needed, this seems to indicate that regular intake of prebiotics could be helpful in supporting sleep patterns after periods of stress.
Gut biome aside, most of us are aware that what we eat affects how we sleep through experience – think of that old saying about cheese and nightmares. There’s some truth in that since heavy, fatty foods are more difficult for the body to process, therefore eating them late at night is not a good idea. Makes sense when we consider that good sleep relies on the release of a complex cascade of chemicals and hormones, and that eating well and allowing the body to absorb proper nutrients provides the brain with what it needs for this to happen.
Various studies suggest eating at a time when we’d naturally be sleeping could have adverse effects on weight and metabolic health and it’s all inter-connected via our circadian rhythm. Our circadian rhythms are what keep our body clock running on time, which in turn keeps all of our bodily functions running on schedule — such as falling asleep at night, waking up in the morning, feeling hungry when we need energy and metabolising the food we eat. What, when and how we eat can help regulate this roughly 24-hour cycle our body follows each day.
Looking at things from a wider perspective often brings us back to ancient holistic wisdom. For example, in the yogic system of Ayurveda it’s believed that digestive fire – known as Agni – is at its most powerful when the sun is highest in the sky, therefore the best time to eat your biggest meal is around midday. And yet how many of us eat our main meal in the evening? This was always my habit – after all, going out for dinner is one of the most enjoyable ways we socialise these days. But, coming in late at night from eating a large meal would inevitably keep me awake, and even if I hadn’t drunk anything, I’d feel like I had a hangover next morning.
Having swapped timings in favour of main meal at lunch or more often brunch, I’ve found eating light in the evening to be a catalyst for better digestion and sleep. That’s not to say I never go out for a big dinner in the evening – it’s just I make it the exception rather than the rule. As always, it comes down to balance, and here are some suggestions for subtly adjusting eating habits in favour of good sleep.
- Introduce prebiotic foods into your diet. These include lentils, chickpeas and hummus, butter beans, globe artichoke, leeks – all of which are a source of the particular type of fibre which encourages the growth of healthy gut bacteria.
- Re-think meal timings considering dim light melatonin onset (DLMO) which is when the body winds down in preparation for sleep and starts producing the sleep hormone melatonin. For most of us, our DLMO usually begins around 8pm so it would be good to time eating before then. Or, allow two hours between eating and bedtime to allow time to unwind and digest.
- Ayurvedic thinking suggests warm, liquid foods are the most easily digested in the evening. So for example, lentil dahl, which tastes great when made with leek; root vegetable soups or stews including lentils or chick peas; sweet basmati rice pudding made with dairy or non dairy milk with cardamom, grated ginger and dates.
- Keep in mind it’s not great to go to bed hungry, considering that our bodies use energy at night when it goes into repair mode. Rather than reaching for typical midnight snacks (crisps, chocolate etc) try hot milk. At one of the best retreats I’ve stayed in in India they brought a pre-bed small cup of locally sourced organic milk, heated with a little saffron. To my surprise, it was the most satiating, satisfying sleep-inducing thing – not to mention delicious.