Eat, sleep, work, repeat: How diet impacts sleep

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We often talk about working life as a relentless treadmill of eat, sleep, work, repeat. A recent study of 81 organisations and 189,000 employees by the management consultancy McKinsey and Company found that sleep affects:

  1. Attention
  2. Concentration
  3. Creativity
  4. Insight
  5. Pattern recognition
  6. Learning
  7. Memory
  8. Decision-making
  9. Emotional reactions
  10. Socio-emotional relationships and
  11. The development of trusted relationships.

These are all pretty critical things for efficient and effective working and we know that sleep is affected by what we eat and drink. We also know that inadequate sleep increases your appetite and this too can have health consequences that reduce our productivity at work. So in this post I take a look at how diet impacts sleep and how the quality and quantity of sleep impacts what we eat and our health in general.

There are 3 key aspects of diet that we know have an impact on how quickly we get to sleep, how long we stay asleep and the quality of our sleep:

  1. Caffeine
  2. Alcohol
  3. What we eat before bed


Caffeine has been shown to delay sleep onset, increase light sleep, shorten deep sleep and increase the number of times we wake in the night. These effects depend not only on the amount of caffeine we consume around bedtime, but also on the amount of caffeine consumed over the whole day. Whilst caffeine may help you feel more alert during the working day studies have shown that the effect only lasts a very short time. So, contrary to popular belief taking caffeine is not a good way to increase productivity.

Caffeine is found naturally in the leaves and seeds of various plants. Natural sources of caffeine include coffee beans, cocoa beans, kola nuts, tea leaves, yerba mate and guarana. Caffeine is also added to energy drinks and some medicines. Coffee and energy drinks are by far the most concentrated sources of caffeine in the diet but if you drink a lot of cola or strong tea you will also be getting a significant intake. We all respond differently to caffeine so you will need to experiment to find an intake that’s suitable for you sleep wise. Generally I find people are better off keeping caffeine containing drinks for the mornings and not having more than 2-3 mugs or glasses. This has huge implications for the workplace where it’s important to find other ways to help people stay alert and to ensure that plenty of caffeine free drinks are available. Make sure staff have access to high fibre foods and protein based foods as these will release energy to the body in a steady flow over several hours which in turn will help people feel more alert. Make sure the options are also low in salt and sugar. Good choices for fibre include:

  1. Potatoes in their skins
  2. Fruits, salads and vegetable options
  3. Meals based on chick peas, beans and lentils
  4. Wholegrain foods such Shredded Wheat, Weetabix, porridge, brown rice, wholemeal cous cous and wholemeal pasta.

Good choices for protein include:

  1. Fat free unsweetened yogurt
  2. Eggs or egg dishes such as omelettes,
  3. Grilled or steamed fish and
  4. Meals based on peas, beans and lentils.

Making sure people take regular breaks will also help and if they can exercise during the breaks even better. See my other posts in this series for more information.


At low doses alcohol has a stimulating effect which is noticeable about an hour after you’ve had a drink. At higher doses alcohol has a sedating effect which lasts several hours.  However there is a rebound stimulant effect 2–3 hours after blood alcohol concentrations fall close to zero. This means that is we have been drinking in the evening we experience the stimulant effect in the middle of the night and become restless or even wake up. Late afternoon drinking, as much as six hours before bedtime, also disrupts sleep, even though alcohol is no longer in the brain at bedtime. The long and short of all this is that alcohol is not going to help you get a restful and refreshing night’s sleep. Alcohol is often a key part of workplace socialising and hospitality but it’s important to be aware of the impact it might have on people’s productivity the next day even if they drink fairly responsibly and don’t get drunk. Events involving alcohol are best kept for occasions where there is no work the next day. However if this is unavoidable make sure plenty of water and other unsweetened non-alcoholic, caffeine free drinks are available.

What we eat before bed

It is hard to make concrete recommendations about what to eat to promote sleep as more research is needed.  However if you find that fatty or spicy foods give you heartburn or acid reflux then these foods are best avoided in the evening as you will feel uncomfortable and this may stop you reaching the state of relaxation needed for sleep.

Tryptophan is an amino acid that promotes sleep and is found in small amounts in all protein foods. The best sources are eggs, soybeans, poultry, meat, fish and cheese. It is a precursor to the sleep-inducing chemicals serotonin, and melatonin. For tryptophan to have a sedative effect, it needs to enter the brain by crossing the blood-brain barrier and to do this it has to compete against other amino acids. Carbohydrates like bread, potato, cereals, rice and pasta stimulate the release of insulin which clears other amino acids from the bloodstream and this may facilitate the entry of enough tryptophan into the brain to make the necessary serotonin and melatonin. A small protein/carbohydrate snack before bed may be the best option for example a poached egg on a thin slice of toast but some people recommend high tryptophan foods at the evening meal and then a small carbohydrate snack like toast before bed. The fact is that we don’t yet have enough scientific evidence to be able to say what is best but if you struggle to sleep you could try these options and see if either help.

Whatever you do remember that your body does not want to be actively digesting food whilst you try to get to sleep so keep bed-time snacks small and avoid fatty foods which take much longer to digest.

Sleep, appetite and weight gain

Finally if you are not sleeping well this can reduce levels of the hormone leptin, which normally helps us feel full and increase levels of the hormone ghrelin which makes us feel hungry. As a result lack of sleep can lead to an increased calorie intake and weight gain. In turn being overweight increases our risk of heart disease, cancer and stroke, puts excessive pressure on our joints and makes it more difficult to exercise. So all the more reason to do everything we can to sleep well for our health and productivity.

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