Eat to beat... depression
Meat, fish, eggs, lentils and other sources of protein should be your culinary weapons of choice in beating the blues. "Studies have shown that adding tryptophan – one of the building blocks of protein – to the diets of people with depression can improve their mood," Ursula Philpot, chair of the British Dietetic Association's Mental Health Group, says.
Eat more oily fish, too. The brain needs Omega-3s, also found in nuts, to perform properly and people who don't eat enough have been found to be more prone to depression.
Wholegrains are important – everything from oats to wholewheat bread are a great source of slow-release energy that will prevent your blood sugar taking a nosedive and leaving you feeling downhearted.
"They – alongside fruit and vegetables – are rich in zinc and folate, nutrients that are important in depression," Philpot says.
And cut out processed foods. People who eat fresh foods have much lower rates of depression.
Eat to beat... your hangover
We all know fry-ups are a friend when it comes to conquering hangovers. The problem is, we tend to eat them too late, says Colin Wilson, research scientist at Water Wellpoint. Any meal eaten before you start drinking helps prevent a hangover, he explains, with fatty foods particularly good at slowing down the absorption of alcohol because they stick to the stomach lining longer.
Don't even think about a fry-up the morning after. Fatty foods will probably just irritate your stomach. Avoid coffee, too – it will further dehydrate you. Reach for the fruit bowl instead, prioritising bananas and kiwi fruit, which can restore potassium to your body. Meanwhile, eggs contain large amounts of cysteine, the substance that breaks down the hangover-causing toxin acetaldehyde.
Eat to beat... brittle bones
Childhood is the most critical time to stock up on milk and dairy products, which provide the calcium to improve the strength and density of your bones. "We deposit around 150mg of calcium into our bones every day until we're around 20. If you don't get enough calcium during this time, when bones are growing and developing, they may never reach full strength," says Azmina Govindji, a dietitian with the British Dietetic Association.
Diet remains important to bones in adulthood, she says. One in two women and one in five men over the age of 50 in the UK will break a bone, mainly because of osteoporosis.
Vitamin D – the sunshine vitamin, which can also be found in foods such as oily fish, milk, fortified margarines and breakfast cereals – is essential in enabling your body to absorb calcium, she says. Meanwhile, Vitamin K, found in foods such as broccoli, plays a role in moving the calcium we ingest from the arteries to the bones. Magnesium, found in chickpeas, nuts, lentils and potatoes, and protein are also essential for building bone tissue.
Eat to beat...high blood pressure
Most of us consume too much salt, says Christina Merryfield, lead dietitian at the Bupa Cromwell Hospital. "Cutting down can help to reduce blood pressure." We should aim not to exceed more than 6.25g, she says.
Studies show that potassium and magnesium, found in spinach, bananas, wholegrain cereal and nuts, can also help lower blood pressure. But don't focus too much on individual food types. Last year, scientists at Lund University in Sweden found that a varied diet of foods containing anti-oxidants, wholegrains and fatty acids could bring blood pressure down by nearly one-tenth.
Eat to beat... epilepsy
If ever there was a condition highlighting the medicinal powers of diet, it is epilepsy. A radical high-fat, low-carbohydrate diet has been found to reduce seizures in up to two-thirds of children. The Ketogenic diet, which has been around since the 1920s, puts the body into a fat-burning state which produces chemical compounds called ketones that stop the seizures.
But despite a study being published in The Lancet Neurology journal three years ago proving its success, there remains widespread professional scepticism. Professor John Duncan, medical director of the Epilepsy Society, says more research is needed to establish why this diet helps some children and not others.
Eat to beat... cancer
The World Cancer Research Fund has found that more than one-third of the most common 12 cancers may be preventable through simple lifestyle changes and tweaking the foods we eat. No one food can prevent its onset, but nutrients from a combination of mainly plant-based foods work together to provide extra protection via health-promoting nutrients and antioxidants. Foods we should eat more of, according to researchers, are tomatoes, beans, onions and garlic, cruciferous vegetables (broccoli, cauliflower, cabbage, Brussels sprouts), berries, dark green leafy vegetables and wholegrains. In fact, vegetarian diets have been found by one Cancer Research UK study as being particularly effective at combating cancer.
Some of the more surprising cancer-beating foods include peanut butter and baked beans, whose high fibre content can protect against colon cancer.
Eat to beat... low energy
Twenty per cent of adults don't eat anything for breakfast and many dieters skip breakfast as a means to lose weight, says Sara Stanner, spokesperson for the Nutrition Society. "But this will leave you lacking energy and impair concentration and performance throughout the morning – research shows it."
The best breakfasts are high in fibre and contain protein, she says. "This promotes satiety and helps with appetite control." Think wholegrain breakfast cereal, muesli or porridge with milk or a poached egg.
Don't overeat at lunchtime – a heavy lunch, especially if you're not used to it, can cause an afternoon slump. "A lighter lunch and a healthy afternoon snack are a better option," says Stanner. Even slight dehydration, where you may not feel thirsty, can leave you tired and lethargic.