First, choose fruits with less sugar. According to research, pineapple, honeydew melon, papaya, kiwi fruit, banana, grape and other fruits have high glycemic index, so dieters should avoid eating too much of these fruits. However, apples, kiwis, lemons, plums, cherries and oranges have low glycemic index, which is a good choice for dieters with fruit meals. Secondly, it is best to eat fruit before meals. Studies have shown that if you eat some fruits or drink 1-2 cups of juice 20-40 minutes before meals, you can prevent obesity caused by overeating. Because fruit or juice is rich in fructose and glucose, it can be quickly absorbed by the human body, so that the blood sugar concentration increases and the appetite decreases. The crude fiber in fruit can also make the stomach feel full. In addition, eating fruit before meals can significantly reduce the demand for fatty foods, thus indirectly preventing the adverse consequences of excessive fat accumulation in the body. But many fruits, such as persimmons, hawthorn, almonds and pineapples, can't be eaten on an empty stomach. In order to lose weight, when eating fruits before meals, it is best to choose fruits that are not too sour and astringent, such as apples, pears, bananas, grapes, watermelons and melons. It is difficult to lose weight after eating fruit. Because eating fruit after a meal is equivalent to eating more sugar, which is easy to be converted into fat and stored in the body, and may also gain weight. Especially don't eat a lot of fruit after dinner, because synthetic fat is most likely to accumulate in the body after eating at night. But some fruits can promote digestion, such as pineapple and kiwi fruit rich in protease, lemon and hawthorn rich in organic acids. And these fruits can be eaten about an hour after meals.