ACIDITY is formed due to imbalance formed in our diet. Excess of acidic food causes acidity. Especially flesh foods causes maximum acidity.
All you have to do is follow the DIET:
Breakfast - fresh fruits.
Lunch - light vegetables containing starch, like carrot, cauliflower, beetroot. Along with this desserts & fruits can be taken.
Dinner - light & foods which are alkaline in nature like tomatoes, spinach, raisins.