Since the diet is the most important factor in the management of obesity, preventive education about diet should be started during the formative years, at the time when eating habits are being established. Excessive consumption of chocolates, ice creams, potatoes, oily foods, etc. are to be discouraged by parents. Children should be habituated to take good amounts of vegetables, fruits and salads in their food. Eating at irregular timings, eating more than 3 times a day in children is not a healthy habit. A person who has 15 kgs. of extra fat in the body, he/she has a store of 1,41,000 cals and can go on for many days without food.

Adults who have to lose weight, have to go on restricted diet and if necessary, periodical short fasts. When a person is on restricted diet particularly on fast, the body fats are broken down and ketone bodies are formed. These are acidic in nature and when they are excess in blood, they cause a condition known as keto-acidosis which results in nausea, vomiting, headache, abdominal discomfort, loose motions, etc. This can be prevented by a simple principle of excessive water intake (i.e., two and half liters per day) apart from other dietary liquids. The ketone bodies are water-soluble and are readily excreted in the urine. Plain luke warm water enema on the day of fasting also prevents headache and restlessness.