HEALTH METZ

Let's talk about refined carbohydrates, shall we? These are foods like white bread and pasta that have been processed to remove the wheat germ. Now, wheat germ is what gives unrefined brown bread and pasta its natural colour and all those lovely nutrients.

But here's the kicker: sugary treats and drinks also fall into the category of refined carbohydrates. When we munch on these treats, our gut quickly breaks them down into simple sugars, giving them a high glycaemic index (GI). This means they cause a rapid rise in blood sugar levels, and any excess sugar is stored as fat.

It's generally recommended that we avoid these foods, or at least reduce our intake. And if we indulge in them before we hit the hay, when we don't have a chance to burn them off, they can wreak even more havoc on our waistline and overall body fat.

Eating foods high in saturated fats, such as takeaways, fried foods and some ready meals, as well as red and processed meats, puts a lot of pressure on our digestive system.

Our guts have to use a lot of energy to digest these foods, signalling to the brain that we're still in daytime, awake mode and disrupting our sleep patterns.

Sleep studies have shown that eating a high-fat meal for dinner causes us to wake up more during the night and spend less time in the restorative, dream-state sleep called REM, or rapid eye movement sleep. It can even affect the way we breathe while we're asleep and lead to sleep disturbances caused by acid reflux.

After a long, stressful day, it can be tempting to reach for a glass of wine, and then perhaps another. We might then go to bed drowsy and fall asleep as soon as our head hits the pillow. Great for sleep, right? Not necessarily...

When we drink alcohol, our bodies release the stress hormone cortisol. So although we may feel relaxed, we're actually under more stress inside. Over time, high levels of cortisol have been linked to inflammation, weight gain and an increased risk of developing chronic diseases such as heart disease and type 2 diabetes.

What's more, when we drink alcohol, we may fall asleep more quickly, but we're less likely to enter the important dream state of REM sleep. This leaves us feeling tired and sluggish the next day.

There aren't many people who don't enjoy the indulgence of a chocolate bar. But as we learned with fizzy drinks, sugar can affect our sleep patterns and lead to chronic lifestyle diseases, especially if we eat sugary foods before bedtime.

Chocolate also contains caffeine, which can disrupt our sleep patterns and leave us feeling tired, drained and sluggish the next day. As a general rule, the darker the chocolate, the higher the caffeine content.

And there's more! Chocolate also contains the stimulant theobromine, which is why eating chocolate makes us feel good. But this is also why chocolate can keep us awake if we eat it before going to bed. This can be particularly bad for your sleep if you're sensitive to caffeine.

Curry, chilli and other spicy foods can have a negative impact on our sleep patterns for a number of reasons. Firstly, they can cause acid reflux and indigestion, which can be so uncomfortable as to prevent us from sleeping.

Also, if we eat a big spicy meal in the evening and then go to bed before it's fully digested, the stomach acid that's working hard to digest a heavy meal can travel upwards and cause heartburn, which in turn prevents us from getting a good night's sleep.

Finally, eating hot, spicy foods will temporarily raise our body temperature, which can also negatively affect our sleep - a higher body temperature has been linked to disturbed sleep. For these reasons, it's best to eat spicy foods as early in the evening as possible.

Unsurprisingly, coffee is perhaps the number one worst thing to drink in the evening because it disrupts our sleep-wake cycle. Caffeine is a central nervous system stimulant that works by blocking adenosine receptors in the brain. If these receptors aren't blocked, adenosine can bind to them, causing drowsiness.

Coffee is great for increasing our alertness and productivity during the day. But if we drink too much (generally accepted as more than four regular cups a day, ideally before lunchtime), we can have trouble sleeping.

In fact, one study found that "consuming caffeine six hours before bedtime reduced total sleep time by one hour". We then wake up the next day feeling tired, reach for more coffee and the cycle continues.

Chips, pretzels, salted nuts and popcorn are all great snacks, especially if we don't have a sweet tooth. But they can also be bad for our sleep.

One interesting study found that eating a salty snack before bed delayed the participants' time to bed and then caused them to wake up several times during the night. Deep sleep is important - it's when our heart and breathing rates drop to their lowest levels as we relax deeply. But we also need the restorative REM sleep, when our brain activity becomes more alert and we start dreaming, to get a good night's sleep. This study found that salty foods can send us into such deep sleep that we lose out on REM sleep, leaving us feeling groggy and unrested.

Diuretic foods are foods that have a high water content and make us urinate more often. If we eat a lot of diuretic foods in the hours before we go to bed, we may find that we get up a lot during the night to go to the bathroom, which will affect our quality of sleep.

Cucumbers, asparagus, beetroot, celery, citrus fruits, watermelon and cranberries are diuretic foods. They're also all low-calorie, nutrient-rich foods that form part of a healthy, balanced diet.

But if you find that you're going to the toilet a lot during the night, it might be worth considering avoiding these foods in the evening and eating them at lunchtime instead. The same goes for water - try to drink most of your eight glasses a day before 8pm.

Ice cream and other creamy desserts and cakes are a tasty, indulgent treat, often eaten as a late night dessert. But because they are high in fat and sugar, they can affect our sleep.

Milk-based foods high in sugar and fat take a long time to digest. So if we eat them in the evening before we go to bed, we're still using energy to digest them. You don't need us to remind you how uncomfortable it is to go to sleep on a full stomach, so maybe leave those treats for lunchtime at the weekend!

Soda, cola and other fizzy drinks are all high in sugar, and drinking them at bedtime, when we're least active, can lead to weight gain. They also often contain caffeine, especially cola, which is known to keep us awake - not what we need before bed.

In fact, studies show that those of us who regularly get less than five hours of sleep a night are more likely to drink sugary, caffeinated drinks than those who get the recommended seven to eight hours of sleep most nights. As well as affecting our sleep, fizzy drinks can increase our chances of developing type 2 diabetes and heart disease.

Despite these sleep-robbing, waistline-increasing foods, all is not lost! Here are some foods that are definitely worth including in your evening meal.