We’ve all been there. A bad nights sleep and the next day you’re eating anything you can get your hands on, preferably white and baked. Worse still, you’re up with the baby at all hours of the night and the only thing that keeps you going between settles is hot buttery toast.

There is no doubt that hunger is linked to fatigue. Studies have shown that just one night of poor sleep can make you give in to your cravings for energy-dense treats the next day. The trouble is, you’re not actually hungry –  those are excess kilojoules you’re eating. It’s no surprise then that 27% of people who averaged 6 hours of sleep a night are 27% more likely to be overweight than 8-9 hours a nighters.

How does sleep affect appetite?

There are a few hormones that appetite in different ways and they’re all affected by sleep.

Leptin is a chemical that tell’s us when we’re full, when it should start using kilojoules for energy. When we sleep, our levels of Leptin rise letting the brain know that we’ve got plenty of energy we don’t need to eat or use up energy (sleeping is easy). Not enough sleep means you end up with too little Leptin – so you’re likely to get that hunger trigger even though you’re not actually low on energy (kilojoules). If you eat, you’re going to store these excess kilojoules ‘for next time’. Constant fatigue can result in chronic low levels of Leptin making you feel hungry often and can even cause your metabolism to slow down.

It gets worse.

Ghrelin is a hormone that’s the opposite to Leptin. It tells your brain when you need to eat and when it needs to stop or slow the use of energy. Ghrelin decreases as well sleep as we don’t need to use as much energy and we certainly don’t need to eat. So if you’re over tired you’re likely to end up with too much Ghrelin, telling you to eat and storing the energy because your brain now thinks there’s a famine.

And even worse

Sleep deprivation increases the stress hormone cortisol which can also increase your appetite. It’s probably the cortisol that makes you crave high-fat, high-fat foods as a quick response to feel better from lack of sleep.

Short sleeps at night can cause insulin levels to stay high (when they should be dropping ready for you to wake hungry in the morning). Losing out on just 30 minutes of sleep can lead to insulin resistance, which can lead to weight gain (and also type two diabetes in the long-term).

Don’t Panic.

There’s plenty we can do. If you’ve got a baby or toddler waking you in the small hours, you can’t aim for an uninterrupted 8 hours of sleep just yet, but we can do some damage control (see point 2).

What you can do

1. Get a better night’s sleep

• Aim for a solid 7-8 hours a night
• No screens 30 min before bed
• Avoid caffeine in the afternoon and evening
• Don’t drink alcohol at night, it might help you go to sleep but you’ll have poor REM sleep
• Get more physical activity into your day
• Address any stress or life issues causing you poor rest

2. Make up for lost sleep when you can

• Nap when the baby sleeps
• Ask for help every now and again so you can get a solid block of sleep
• Use your down time wisely. If you can’t sleep, meditate or just switch off and relax.
• Make time to exercise and relax everyday. Even a few minutes can be enough to reduce cortisol levels.

3. Be prepared for the snack attacks.

If you’re eating well then chances are you’re not actually hungry when the cravings hit. Try to distract yourself by removing the temptations, having a herbal tea or better yet, go for a walk or a quick burst of activity outside.

You’ll naturally be craving  simple carbs, they’re quick and easy to digest but spike blood sugar levels and don’t give you many nutrients. If you’re going to snack, have some more wholesome foods on hand ready to eat instead. Your self-control won’t be at it’s best so make sure the healthy choice is the easy choice.

• Dense, grainy whole grain bread. Spread with hommus or natural peanut butter
• 30 g mixed fruit and nuts in small snack bags
• Cut up veggie sticks and dip in containers in the fridge
• Portion controlled sweet treats, like these delightfully fluffy (but low-ish sugar) wholemeal muffins

If you find yourself constantly tired or suffering from poor sleep, have a chat to your GP.

Sarah Moore is a Registered Nutritionist in Perth, Western Australia. She offers group education sessions and private consultations.