This question doesn’t have a simple answer, as it depends on what kind of exercise you’re planning on doing. As a general rule, although you shouldn’t eat too much of anything right before doing any kind of intense physical exercise, you should certainly eat enough to give your muscles the energy they need for a good workout. So, what kind of sport are you into?
Running. Whether you like a good session on the treadmill, pounding the streets, cycling or any other high-intensity activity, you should eat some slow-release carbohydrates. That way you will make sure your muscles get the energy they need and you’ll avoid energy spikes. Wholemeal cereals, pasta and rice or simply a slice of brown toast with extra-virgin olive oil are great solutions.
Swimming. The vegetable fats in nuts will help keep your body temperature steady while you’re swimming. Remember to eat proteins afterwards.
Weight training. Your muscles need plenty of protein to work. Animal protein (white meat, eggs or fish) is best as it is absorbed more quickly and is what your body needs to build up muscle mass.
Yoga or pilates. If you’re planning to do gentle exercise, you can eat some carbohydrates, a simple yogurt with nuts or a piece of fruit beforehand. If you’re not hungry before your session and you’re not going to burn much energy, you don’t have to eat anything beforehand. But make sure you eat something afterwards!