Do you eat more when you’re feeling tired? You’re not imagining it. HFG investigates how you add centimetres to your waistline when you run short of sleep — and how to overcome this.
We’ve all experienced a bad night’s sleep. Whether it’s stress that’s keeping you up, a crying baby or just a restless night, it can leave you feeling tired, irritable and low on energy.
Lack of sleep can also affect your concentration, coordination and immune system — not to mention the impact it has on your overall wellbeing and happiness. We all feel better after a good night’s rest. In fact, a study by Oxford Economics found that having a sound sleep was as good at boosting mood as having four times our disposable income.
New research has also revealed that getting enough shut-eye can be vital to maintaining a healthy weight. If you think you’re missing out, here’s what you need to know — and do. Sleepwalking through food
Think about the last time you had a poor night’s sleep — and what followed. You probably snoozed your alarm a few too many times, which meant you didn’t have time for breakfast before running out the door. Then, when you got to the coffee shop for your morning brew, you were easily tempted by the mouth-watering muffins sitting on the counter.
As 3pm rolled around and the yawning set in, you went on auto-pilot in search of sugar to combat the relentless fatigue. Sounds familiar? It’s easy to see how this cycle can lead to weight gain over time — but it’s also important to know how your body’s physiology contributes to it.
Why the junk food cravings?
Have you ever had a late night out and woken up craving a salad? Didn’t think so. What’s more likely is you went for something with a little more fat or starchy carbs — the foods that we know accelerate weight gain and associated diseases like diabetes.
Studies show cravings for sugary sweets, heavy carbs and salty snacks increase by more than30 per cent when you’re tired, compared with food choices you make when you’ve had eight hours sleep. But why do we lust after these foods?
It seems we physically ‘switch off’ our better judgement when we’re tired. A research team at the University of California scanned people’s brains while they were viewing food items — once when they’d had a full night’s sleep, and once when they were sleep deprived. The team then rated how much the participants desired each food. It discovered that the rational control regions at the front of the brain, which normally keep our hedonistic food desires in check, had shut down. Worse still, the more primal, deep-brain structures that drive impulsive decisions were revved up in response to desirable food images.
Without sleep, your body shifts to a more primitive pattern of brain activity that favours uncontrolled impulsivity, making you reach for a giant muffin rather than healthy leafy greens.
When your hormones run riot
Without enough sleep, your hormones become unbalanced and confused. In particular, your hunger hormones leptin and ghrelin start to fluctuate, making it hard to stick to healthy eating.
Leptin tells your brain you feel full, so when levels are high your appetite is blunted and you stop eating. Ghrelin, by contrast, ramps up feelings of hunger, so when the hormone reaches elevated levels you feel hungry and want to eat more. Generally, a healthy balance exists between these two appetite hormones.
Lack of sleep distorts this balance, however. Take a group of healthy, fit individuals and limit them to four-to-six hours sleep a night for several nights (as countless research studies have done) and you see a striking rise in levels of ghrelin, leaving participants feeling constantly hungry. At the same time, levels of hunger-suppressing leptin decrease, unleashing an extraordinary appetite.
What follows is perhaps all too predictable. Participants in these studies ate 1200–2000 more kilojoules at each meal than when they’d had eight hours sleep. Worse, despite eating more, they didn’t feel satisfied by the food. It’s the appetite equivalent of all accelerator pedal and no brake.
Is diet disrupting your sleep?
Certain things you eat or drink can really affect your sleep.
Caffeine is a stimulant, so you might find it makes it harder to fall asleep. You could sleep more lightly, wake frequently or need extra trips to the bathroom. Caffeine is not found solely in coffee — some teas, energy drinks and soft drinks have it too.
Dishes with plenty of chilli and garlic can cause you heartburn and indigestion, making sleep difficult, so you might need to lay off late-night curries with a good night’s sleep in mind.
Creamy pastas and deep-fried dishes delay digestion, which means you could have a restless night. These types of foods can also trigger heartburn.
While a nightcap might help you doze off, you’re likely to wake throughout the night and have a less restful sleep — so try your best to cut down on booze.
Loosing all the wrong weight
Skimping on sleep gets in the way of your weight-loss efforts, too. Even when you’re carefully cutting down kilojoules, if you sleep just five-to-six hours a night, 70 per cent of the weight you lose will come from lean body mass such as muscle, and not fat. Basically, your body becomes especially stingy in giving up fat when it’s sleep deprived — so dieting is ineffective.
Obesity isn’t caused by lack of sleep alone, of course, but research shows the sleep-loss epidemic is a key contributor to the obesity tsunami. Sadly, we’re now seeing these effects very early in life. Three-year-olds sleeping just 10.5 hours or less have a 45 per cent increased risk of being obese at age seven than those who get 12 hours. But there are steps we can take!
10 tips for a better sleep
1 Don’t go tot bed full
Too much food in the evening will make you uncomfortable and prone to indigestion. To give your body time to digest food, leave around three hours between having your last meal and going to bed at night.
2 Don’t go to bed hungry
Although you don’t want to eat too much too late, you don’t want to be lying in bed with a rumbling stomach either. A smallish bedtime snack (about an hour before hitting the hay) can help keep your blood sugar levels steady throughout the night. If you’re hungry, try a chopped banana with reduced-fat plain yoghurt, or a slice of grainy toast with peanut butter.
3 Avoid caffeine
Aim to have your last coffee at least four hours before bedtime. Instead, unwind with a soothing cup of chamomile tea, which has been shown to have relaxing properties due to its flavonoid compound chrysin.
4 Get moving
Exercise can promote ’40 winks’ as it helps to relieve stress and tension. That doesn’t mean you have to pump iron or pound the pavement all day either. Find a routine you enjoy and stick with it. For a good night’s sleep, avoid vigorous exercise close to bed time.
5 Get in the mood
Your bedroom should strongly be associated in your mind with sleep — not with work or TV-watching.
Include a relaxing activity in your bedtime ritual, such as reading or stretching, to give you time to wind down.
6 Switch off the screens
Remove TVs, phones, iPads and laptops from the bedroom, as their blue light suppresses production of melatonin, the hormone that makes you feel drowsy.
7 Don’t rely on weekends
While there’s nothing wrong with a bit of a sleep-in, try not to use the weekend to catch up on sleep. We’re creatures of habit, so our bodies find it hard adjusting to changes in sleep patterns. Sleeping in on the weekend will only make it harder to wake early on Monday.
8 Quit smoking
Like caffeine, nicotine is a stimulant, so it makes falling asleep difficult.
9 Have a glass of milk
A small glass of warm milk might help you doze off, due to its tryptophan content. Tryptophan is a proven precursor to serotonin, a brain chemical that induces sleep. Nuts and legumes are also good tryptophan sources.
10 Stick to a routine
Set your alarm clock for the same time each day, and go to bed on time too — even on the weekends. Aim for some daylight exposure early in the morning, which helps reset your body clock.
Melissa is an Accredited Practising Dietitian with a love of healthy, delicious food. She is passionate about helping others to lead healthier lives and teaching people to use nutrition to better their health.