Why does lack of sleep lead to such bad food choices?

Sleep plays a crucial role in appetite regulation. Here are some ways to avoid eating the wrong foods when you’ve stayed up all night.

Let’s picture a scenario. One we’ve all experienced before.

You’re up late for that big presentation the next day. You’re staring at the laptop screen and checking the smart phone. You finally hit the hay around 2 am.

At 7 am, the alarm goes. Instead of your usual omelete, you reach for the box of Cheerio’s. You tell yourself, it’s just less hassle this morning.

But at 11 am, when it’s time for your mid morning coffee, instead of your usual apple, you can’t keep your eyes off the chocolate muffins. You grab one, acting on autopilot.

If this scenario sounds familiar, and you’re struggling to lose weight, eating on impulse a little too regularly, consider that it might have nothing to do your willpower.

It could be down to your sleep patterns.

The science of sleep and appetite regulation

According to a 2013 National Sleep Foundation poll, most of us need around 7.5 hours of sleep to be at our best. Yet we average 6.5 hours per night, with up to 30% of adults in the US getting less than 6 hours shut-eye.

The consequences are not trivial. In our scenario, you thought you ate the Cheerio’s because it was convenient. You thought you ate the muffin because you were a bit more tired than usual.

You’re wrong; the reason you made unhealthy, high calorie, high sugar food choices is down to your lack of sleep.

Sleep and obesity - Sleep Junkies

Circadian rhythms

To understand how sleep affects appetite and how we process food, we have to understand how our body clock, or circadian rhythm works.

Our circadian rhythm operates on the natural 24 hour cycle of light and dark. Jet-lag is a prime example of what happens when you desynchronize your body clock.

Apart from determining our energy levels and how tired we feel, sleep and circadian rhythm play a huge role in regulating our appetite, and processing food intake.

For this reason, disrupting your sleep and body clock can put you at risk for weight gain, obesity and type-2 diabetes. Let’s look at how.

Blood sugar

Lack of sleep has the same effect on your ability to manage blood sugar as someone who suffers from diabetes. Both diabetics and the sleep deprived can end up with consistently high  blood sugar levels. Over time, this can damage the body and lead to many health problems.

In our example, the high sugar content in the chocolate muffin and Cheerio’s literally has nowhere to go, because poor sleep disrupts the balance of many hormones, including insulin which is responsible for managing blood sugar levels.

This results in abnormally high blood sugar levels, and a state known as prediabetes, which is often a warning sign that you may develop full blown diabetes.

But ending up in this pre-diabetic state doesn’t just happen after you’ve pulled an all-nighter. While the effects are particularly pronounced with between 4-5.5 hours sleep, the same effect can accumulate over time, from 5 or more consecutive nights of sleeping 90 minutes less than your habitual sleep time.

Appetite and food preferences

The irony of ending up in this temporary pre-diabetic state, is that your brain is telling you to go and eat the exact thing your body can’t handle – ie carbs. Hence the Cheerio’s and muffin were not a random choice. The desire for high carb, high sugar foods increases by 30% when you’re sleep deprived.

Hunger hormones

Leptin, the hormone in the brain that signals “I’m full”, drops by 18%. Ghrelin, the hormone in the gut that signals “I’m hungry” increases by 28%. Together, this combination turns you into a weapon of mass consumption. One study found a single night of sleep deprivation increased calorie intake by 22% during the subsequent day.

You eat more after a bad night's sleep

Imagine you need around 2,500 calories a day to maintain a healthy weight. Now imagine having 1,000 calories taken away from you: you’d be starving. But this is what happens to our hunger hormones when we lack sleep.

What follows is similar to binge-eating after an extreme diet. You get hungrier, but gain less satisfaction from your food. This is because lack of sleep inhibits the effect of a hormone called PYY  which regulates food intake.

This explains why the 11am muffin proved to be so irresistible. Lack of sleep confuses the food-reward and inhibition mechanisms in the brain, leading us to overcompensate above our energy needs, with a preference for high sugar, high carb foods.

The night-time danger zone

But if you thought mornings were the worst time for sleep-related poor food choices, think again. Research shows you’ll eat more calories after dinner. The primary culprit for this increased calorie intake? Snacks. In particular, highly palatable, energy-dense, high sugar and fat snacks. Raiding the pantry at night-time is more likely to be the result of a less like a tough day than that of an unregulated body clock.

How to make better food choices when you’re sleep deprived

The question is, how do you avoid the Cheerio breakfast, 11am muffin, and evening binge on those inevitable occasions you don’t get adequate sleep? The following steps will help:

1)Deal with breakfast (Option i).Consider skipping your breakfast, and pushing your first meal back later in the day. This is because fasting is the most effective way of regaining control of your blood sugar management.

The effects begin to occur around 12 hours from your last meal. So work backwards from your last meal, and aim for 12-18 hours after before you chow down again. If you had dinner at between 7-8pm the previous day, then aim for 1pm.

2)Deal with breakfast (Option ii). If you’re sleep-deprived, fasting might not be an easy option, given the lack of appetite regulation. In this case, focus on low-carb, high protein and fat meals for breakfast.

Breakfasts like these lead to greater fullness and better blood glucose regulation. Breakfasts containing protein and fat suppress the stimulation of hunger hormones. So think eggs and avocado.

3)Eat protein with each meal: High protein intake reduces food stimuli, and decreases reward-seeking food behaviours, so that 11am muffin will be less appealing. Remember that most calories come in the evening? High protein intake throughout the day can decrease your food intake at subsequent meals. Aim for around 250-300g meat, fish, or poultry, or 300-400g lentils, beans or legumes for plant-based diets to cover.

4)Time your carbs:  Carbs have one very unique role in the sleep picture. While you want to avoid the high sugar foods during the day, in the evening to help get your sleep back on track, you don’t want to keep carbs too low.

Not having enough carbohydrates can decrease REM sleep, increase sleep onset time, and increase light-phase sleep. Carbs can also boost brain levels of melatonin, the hormone that promotes sleep. So add some good quality carbs to your dinner – think sweet potatoes, quinoa, lentils, rice.


Now you know why unregulated sleep and body clock may the biggest hindrance to getting your diet on track.

But life gets in the way, and we can’t always engineer the perfect night’s sleep. For the times when you need it, use the steps outline above to prevent less than optimal sleep from derailing your diet.

Alan is a Nutritional Therapist coaching nutrition for wellness, fitness and clinical purposes. Alan is a Certified Nutrition Coach with Precision Nutrition, and a Certified Fitness Trainer with the International Sports Sciences Association.

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