Your diet is one of the three pillars of your mental and physical health, the others being lifestyle and herbs.
Ayurveda, comprised of the five elements, teaches you which foodstuffs agree with the elements prevalent in your type, or dossier and which would tend to aggravate it.
For example, if you are a space and air type (Vata), the characteristics of your elements are cold, dry, mobile and light, to name but a few. When in balance these would cause you to be creative, witty, and to learn things quickly (and forget them just as fast, as you go on to something new). When out of balance, these would show up as dryness of skin, hair, nails and joints; insomnia; lack of concentration; pain and excessive talking. Emotionally you might be suffering from fear, anxiety and dizziness. If that’s the case it’s time to soothe the nerves by eating warm, heavy, unctuous foods, such as a soup made of sweet potatoes and carrots with a dollop of cream in it and add ginger to your food where possible.
Conversely, you might find that, being a fire person (Pitta) - normally a good manager and leader, a people’s person - that you are suffering from jealousy, anger, control issues, pride ambition and other emotions related to the ego. Physically this might manifest as excema, urticaria, rashes, infections (perhaps in the eyes, a Pitta organ) and acid reflux. If so, try eating cooling foodstuffs such as apples (remember to eat fruit away from a meal), cucumbers, dairy (but not yoghurt) especially ghee and add turmeric to your food where possible.
And if you are a water and earth person (Kapha), you may find that you have put on a bit of weight, even being obese, and/or are suffering from phlegm and colds. Emotionally, when in balance, you are loving and forgiving but when out of sorts you tend to hold on, including to weight. The characteristics of water and earth being cool, heavy, sluggish, oily you want to fire yourself up by adding all kinds of spices to your diet, although fenugreek is particularly good. Avoid dairy, sugar, heavy foods and sauces and make sure you perspire for half an hour a day!
By following the right diet for your type you can use your food as medicine.