Recently, the American Medical Association officially announced that obesity is defined as a disease. Obesity has attracted more and more attention. Faced with the "great cause" of losing weight, everyone can say that they have their own "theory". A few days ago, Zhang Xin and Pan Shiyi, lovers in the real estate industry, respectively "publicized" their weight-loss methods in Weibo. Zhang Xin said: Drink two cups of juice and four cups of vegetable juice every day, and you lose three kilograms in a week. Pan Shiyi even went on a business trip with a blender and a kitchen knife. Is it advisable for them to lose so much weight? According to experts, it is impossible to lose weight by drinking fruit and vegetable juice. For Zhang Xin and Pan Shiyi's weight loss methods, Gu Zhongyi, a nutritionist in the Nutrition Department of Beijing Friendship Hospital, shouted in Weibo: This is a textbook-level weight loss error demonstration. He said that eating only fruits and vegetables has advantages and conforms to the imagination of "clearing the intestines" and "health", but it is impossible to lose weight by drinking only fruit and vegetable juice for a long time. In the end, it was completely futile. Because of the weight you lost, you will come back soon. Experts point out that this diet will disturb metabolism. You may get a lot of sugar, but without any carbohydrate intake, people will often feel dizzy. If there is no fiber intake in the diet, constipation will occur in a few days, and more seriously, cholesterol will skyrocket. Drinking fruit and vegetable juice sounds like taking a lot of vitamin C, which is good for your health, but only if you don't give up the nutrients in other foods, such as calcium, protein, vitamin D and fat. Experts say that if you want to eat more fruits and vegetables in your diet plan, it is recommended to eat vegetables and fruits directly instead of making juice. This kind of weight loss is far more harmful than obesity itself. "If you only drink juice and vegetable juice for three meals a day, you will definitely suffer from malnutrition in the long run and affect your health." Nong Shao Zhuang said that protein plays an important role in the constantly running machine of human body, while the content of protein in fruits and vegetables is relatively low, so the biggest impact of such dietary adjustment on the body is to reduce the intake of protein. If the human body lacks the necessary protein, the functional resistance will be weakened, the immunity will be reduced accordingly, and people are more likely to get sick. Nong Shao Zhuang warned that long-term use of fruits and vegetables instead of staple food will also lead to premature aging such as decreased skin elasticity, hair loss, loose teeth and tooth decay. Moreover, there is no evidence that eating fruits and vegetables processed by blender or juicer will increase health benefits, absorb nutrients quickly through fruit and vegetable juice, and may even cause problems. Nutritionists also warn that the rapid absorption of sugar in food or juice may lead to a rapid rise in blood sugar, especially for diabetics. Nong Shao Zhuang said that the content of protein, calcium and iron in fruit is not high, and it can't provide all the nutrients needed by human body. If you don't touch chicken, duck, fish and other meat for a long time, you may also lack zinc, calcium, iron, vitamin B 12 and various minerals, which may lead to other diseases. In fact, balanced nutrition can keep you healthy. Fruit and vegetable juice can be drunk reasonably and has more comprehensive nutrition. "Fruit and vegetable juice is not completely undesirable. The key lies in how to mix it reasonably." Nong Shao Zhuang said that for the average adult, about 2,000 calories are needed every day, of which about 15% comes from protein. According to equivalent conversion, about 75 grams of protein is needed. According to the requirements of the World Health Organization, the human body needs at least 1/3 (i.e. 25g) of high-quality protein in daily protein to ensure the healthy operation of the human body. In addition to beans, animal meat such as chicken, duck, fish and lean meat is the main source of supply. Secondly, the absorption rate of iron in food varies greatly, and iron in animal food is the most easily absorbed, which is less affected by dietary factors. Iron in plant food is greatly influenced by dietary factors. At the same time, fruit and vegetable juice with high dietary fiber will make people consume a lot of oxalic acid or phytic acid, which will also reduce the utilization rate of minerals such as iron, calcium and zinc, and also need to be supplemented by the intake of other foods.