More or less protein? The foods to get you through a heatwave

As temperatures exceed 30C (86F) in some parts of the UK this week, the last thing people want to do is turn on the oven.

Not only can cooking in hot weather feel like a chore, but many of us find ourselves feeling less hungry altogether.

So when the heat gets too much, should we consider changing our diet?

Here are four things to think about next time you're hot and hungry.

"There's no need for more protein in a heatwave," says Aisling Daly, senior lecturer in nutrition at Oxford Brookes University.

But if you fancy it, most protein will need cooking (like meat, chicken and fish) and that can be off-putting in the heat. Even an outdoor BBQ can be too hot to handle.

Enter the air fryer. Cooking a chicken leg or a potato in the worktop device uses less than half the energy of a conventional oven, according to Radio 4's Sliced Bread. And because they are smaller and speedier, they also pump less heat into your kitchen.

But experts say don't forget about your slightly less fashionable slow cooker - likely buried in the back of your cupboard. Even though they run for longer, they're typically more energy efficient and release even less heat than the air fryer.

The reality, though, is that simply by eating and digesting protein, our bodies produce more heat than other food groups.

That's due to the energy needed by the stomach, intestines and liver to break down and absorb these complex molecules.

So that steak you crave will only bring you out in a sweat. Try fruit, veg and carbs instead - as all are easier to digest.

Dr Daly recommends pre-cooked meats, alongside things like bean salads, eggs and plenty of Greek yoghurt (frozen too).

Making a smoothie by blending up fruit, veg and yogurt (while adding in peanut butter for protein) can provide a balanced, nutritious meal in an easy way.

And it might also be time to turn to some lighter fish, such as tuna, salmon or prawns. For vegetarians, you can get your protein from lentils, nuts, milk, tofu and cheese too.

When it's hot, we lose water when we sweat, so we need to replace it or we become dehydrated.

Six to eight glasses of fluid a day is normally recommended by the NHS, and in a heatwave you could need a lot more.

"There is no single amount that suits everyone, because how much fluid your body needs depends on lots of factors like your age, body size, activity levels and health status," says Dr Charlotte Mills, food and nutrition scientist at the University of Reading.

World Cup footballers aren't the only ones who benefit from hydration breaks: other athletes and pregnant and breastfeeding women are among those who need to drink more.

But rehydrating doesn't just mean refilling your water bottle every couple of hours.

"We need to eat our water as well as drink it," says Dr Daly, "80-90% of fruit and vegetables are full of water."

Cucumber, tomatoes, lettuce, celery, watermelon and strawberries all have very high water content, above 90%.

Apples, carrots, cooked broccoli and pears contain 80% to 89% water, as do oranges, grapes and pineapple.

In comparison, boiled eggs are 75% water, with digestive biscuits only 2.8% water. Even a cheese and tomato pizza is 38% water, with takeaway chips containing as much as 51%.

If your mouth has dried up just reading this, try some of these water-rich recipes.

If you're not sure how much liquid you're taking in, you can always check the colour of your urine.

Pale yellow is what you're after.

If it's orangey or dark brown, that's a sign that your kidneys - which filter waste products and produce urine - are holding onto water because there isn't enough in the body.

That means you're dehydrated and need to drink more.

Feeling tired and unfocused is also a sign that you need more liquid. Heat exhaustion can turn into heatstroke which is a medical emergency.

We know some people love a cuppa, even when it's sweltering, and that actually makes scientific sense.

Warm or room-temperature drinks are just as good as cold ones for cooling you down, says Dr Daly.

Research suggests your body sweats more quickly to get rid of the excess heat after a hot drink. After a cold drink, your body sweats more slowly. Your body is trying to keep your core temperature steady at about 37 degrees celsius.

So hot tea won't necessarily help you cool down more quickly - the key thing is to stay hydrated no matter the temperature of the liquid.

You don't need to shun your favourite coffee either just because it's hot - although too much caffeine can make the body produce more urine, and leave you dehydrated.

For matcha fans, the drink contains more caffeine than a cup of tea but less than a regular coffee.

Dr Daly says one or two coffees a day should make little difference to your hydration levels - but five or six will start to have an effect. Bear in mind that drinking alcohol also dehydrates.

You could structure your day differently too, and take a southern European approach to eating. Have an early breakfast, an afternoon siesta while it's very hot and then a late dinner. Bon appetit.

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