I hated exams and I still remember how my mind would go blank when faced with a question paper. I’d forget everything I’d revised, often dissolving into tears.

As the years passed, though, I began to realise that my exam performance was affected by how I ate while studying and, most importantly, what I consumed on the day of the exam. If you have a school-age child, the following tips may help them, too.

Water refresher
Studies suggest that children who drink plenty of water find it easier to concentrate, retain information and do mental arithmetic, and also get fewer headaches. Ideally, place a jug of water (tap or bottled) on your child’s desk but, if they turn up their nose at pure water, you can flavour it with a high-juice or no-added- sugar squash.

Watch the fizz
Although sugar can improve concentration initially, an overload can have the opposite effect. It can make children hyperactive and headachy, then causing energy levels to drop so dramatically that they just want to fall asleep. This is why canned fizzy drinks are the last thing that you should give them.

Juices with lots of added sugar have a similar effect. So, if you want to get some vitamin C into your child, use a little freshly squeezed juice diluted with plenty of water.

Some highly processed drinks contain additives such as tartrazine, a yellow colouring that can aggravate hyper-activity and disrupt concentration. So try to get your child to drink as much unadulterated water as possible, right up to the morning of an exam. Timing is important here because no one wants to be worrying about going to the loo in the middle of things.

Go easy on the caffeine
Colas and other tannin or drinks that contain caffeine such as coffee and tea might aid concentration in the short term, but I don’t recommend them. They can make children hyperactive and scatty; also, the tannins inhibit the body’s ability to absorb essential nutrients such as iron and calcium.

And if children get into the habit of relying on caffeine to keep them awake while cramming late into the night, they are more likely to feel tired and panicky the next day and forget what they’ve learnt. Still, if your child has had a good night’s sleep and needs a pick-me-up, a cup of weak tea in the morning may provide a gentle boost.

Hold the chocolate
Chocolates, sweets, biscuits and other foods high in sugar are best avoided during re- vision, as are sugar-packed cereals on exam mornings. Sugary foods have a profoundly negative effect on children’s behaviour, including their ability to study and sleep well.

Healthy nibbles
If your child needs a snack, urge him or her to eat fresh or dried fruits, unsalted nuts, a sandwich, a yoghurt, a bowl of soup, a fresh-fruit smoothie or a piece of cheese.

Although crisps don’t contain sugar, their fat content makes them hard for a nervous stomach to digest so, if your child’s anxiety tends to manifest itself as tummy ache, avoid them.

If starchy foods such as pasta, rice, potatoes and bread make your child feel sleepy, these are useful allies to enlist at night to promote brain- refreshing sleep.

Have a good breakfast
On the day, however, go for a high-protein or high-fibre breakfast (eggs, beans or mushrooms on toast, or a wholegrain cereal such as porridge, muesli or Weetabix which provides slow-release energy) and high-protein foods such as beans, meat, fish, eggs or cheese, plus vegetables and fruit later on. For those feeling too nervous to eat much, a couple of bananas, some raisins or a fruit smoothie will help them to keep going through this angsty time.

Jane answers your questions in times2 on Tuesdays; e-mail Jane.Clarke@thetimes.co.uk and visit www.jane.clarke.com.

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