Taking care of food, water and air is very important for achieving good health and protecting it. To get oxygen which is the life force, one should regularly sit or walk in a place full of greenery. Food and water should be clean. One should be careful in buying groceries as these days adulteration is a common phenomenon. Fried and spicy food and food items made of thickened milk and white flour are harmful. They ruin the digestive system, and make one susceptible to all kinds of diseases. Irregular meals and overeating are harmful too. One should take plenty of water. Chewing the food well and drinking water slowly is good for health. One who eats a little less than what the appetite demands, is seldom sick and is more active. A sick person has to be all the more careful about all the above details.