There are 16 million overweight people in Italy and 5.4 million who are defined obese, an increase of 25 percent in the last five years. In Rome one child out of six is obese and one out of three is overweight. To discover whether one's excess weight has reached the point of being detrimental to one's health the Italian Association of Dietetics and Nutrition recommends measuring one's circumference at the height of the belly button. If a woman measures more than 88 cm (and a man 102 cm) they should go on a diet urgently. A more accurate approach consists in calculating one's so-called body-mass index by dividing one's weight in kilograms by one's height squared. If the result is from 26 to 30 points the person is considered overweight; over 31 he or she is considered obese.