Driver Knowledge Tests

How does food and drink affect your performance in your driving test?

You are what you eat is not the case, but what you put into your body does have immediate effects both on your ability to drive and the comfort of your passengers. For these reasons you should consider what foods and drinks you are going to consume on the day of your practical driving test.

Spicy food

Culturally your food might be heavily spiced or laden with garlic and other good stuff. Spicy food is great if everyone’s eaten it, but not so good if you’re the one that hasn’t. It’s much safer to lay off the garlic and strong spices so that you don’t offend the olfactory system of the driving instructor. After all, you’re in a small, enclosed glass and steel box and you don’t want to give them the desire to end the test early.

Foods that give you gas

If you know that baked beans are not your friend, don’t eat them. There’s only so much that air conditioning can cope with therefore it’s best if your digestion remains placid.

Fatty foods

Fatty foods, especially those that also have a heavy protein content such as a pie, will make you feel lethargic. If your test is early afternoon your body will want to digest your lunch. Couple this with your natural circadian rhythm and it will make you feel sleepy. Your reaction times will be slower and it will be harder to remember facts and process instructions. If you are at all dehydrated the effect will be worse. It’s best to eat a light lunch with plenty of vegetables.


Sugary foods will give you an instant energy burst, but they will dull your reflexes, and once the energy has gone you will feel more tired. If you feel you need a sugar hit, take it in the form of fruit, not sweets.


Your brain is mostly water (around 75%) and when you get dehydrated it can affect your ability to think, as well as give you a headache. Dehydration also can cause bad breath and constipation. Make sure you drink enough water.


Striking the balance between dehydration and needing to go to the toilet every 15 minutes is one you’ll need to experiment with. If you’re busting to go, you’ll be distracted. Make sure you go just before your test.

Alcohol, stimulants, sedatives and irritants

Always avoid alcohol. Even very small amounts of alcohol will affect your driving ability. Also, if you have cultural foods that you ingest which cause a change in your mind or body’s state, avoid these, too.

If there are foods you know that give you stomach ache or other physiological symptoms, avoid these as you don’t want to be distracted by them on your test.

What should you eat and drink?

Brain foods

Foods like salmon have omega-3 and omega-6 oils that help support healthy brain function. The protein will also keep you feeling full for longer. Walnuts have similar properties.


It’s all you need for hydration. Try to avoid sugary drinks. Water is easy to absorb and is neutral.

Fruit and vegetables

These will give you vitamins, minerals and energy, as well as the water content. Some fruits, like apples, can give you a boost similar to coffee.

Having said all this, if you usually function on a certain type of diet, changing it for one day can upset your system. If you do plan to change what you eat, test it out beforehand to check there are no adverse effects.

Darren is an expert on driving and transport, and is a member of the Institute of Advanced Motorists

Tagged with: , , ,
Posted in Advice, Car, Heavy Vehicle, Motorbike