With my two years' experience in the gym, it's not particularly easy to answer, because I started working out from being overweight. However, many of my friends and colleagues are thin-skinned and have achieved certain results. I learned something when communicating with them, and combined with the information I found, I summarized it below for reference. By the way, please don't call me "teacher" next time. First, improve the digestion and absorption function of the stomach. Many people are thin, not because they eat less or have insufficient nutrition, but because the digestion and absorption function of the stomach is not enough and they eat for nothing; And some people will not grow strong even if they make up for it. Therefore, fitness and muscle training should start with improving the stomach and intestines. -You can see a doctor to diagnose your stomach and prescribe the right medicine. Because wasting is divided into simple wasting and secondary wasting. Simple emaciation has no definite endocrine disease, and secondary emaciation is caused by organic diseases of nervous system or endocrine system. If it is secondary emaciation, please do fitness exercise after recovery. -You can usually eat more things that can strengthen the stomach and help digestion, such as hawthorn slices, apple vinegar and auxiliary drugs. -Exercise regularly. Exercise can promote the digestion and absorption function of the stomach (let's talk about how to exercise from another angle here). -Stick to a regular diet, chew slowly and eat three or four meals a day. -No smoking, moderate drinking. -Be sure to eat hygienic and clean food to prevent diarrhea. Second, increase proper nutrition-drink honey water (I drink it every day in autumn and winter), because first, honey can inhibit gastric acid secretion and promote ulcer healing, and second, it can moisturize and improve defecation. -Be sure to insist on eating breakfast. -can't be a partial eclipse. Pay attention to increasing the types of food, carefully mix fish, meat, eggs, milk, vegetables and fruits, and eat everything to ensure adequate nutrition and ensure that the food you eat every day contains enough calories. Choose excellent protein sources, such as eggs, milk, meat and poultry, which should account for more than half of the daily protein. Soybean protein powder separated and extracted from plant protein will have better effect, because there are fewer plant fibers that hinder absorption. -conditional drink all kinds of nutrition porridge. -It is recommended to drink more yogurt instead of milk. —— One hour before exercise, be sure to eat something that provides calories; Protein and proper carbohydrates should be supplemented after exercise. (Source: Fattening Network www.5yzf.com) Third, adhere to regular exercise-understand that we are gaining muscle, not weight, so both weight-bearing and aerobic exercise are needed, but aerobic exercise should not be too much, mainly weight-bearing exercise. -Exercise regularly 3-4 times a week for about 60-90 minutes each time, depending on physical strength. -You can train two muscle groups at a time, each muscle group does 4-5 movements, each movement does 4-5 groups, and each group does 8- 10. The weight is medium, but the maximum weight can be 1-2. Fourth, the law of life-to ensure adequate sleep time, it is best to fall asleep between 23: 00 pm and 5: 00 the next day. Try to have your own spare time, don't let work occupy all your waking hours, and don't bring work into your life. Fifth, try to make your mood happier. Whether your stomach is healthy or not has a lot to do with mental factors. Excessive mental stimulation, such as long-term tension, fear, sadness, depression, etc., will cause dysfunction of cerebral cortex, promote dysfunction of vagus nerve, lead to spasmodic contraction of gastric wall blood vessels, and then induce gastritis and gastric ulcer. -Always cheerful, cheerful and strong-willed. When you encounter negative emotions, try to solve them by talking, exercising, reading and entertaining, so as to extricate yourself from the predicament. -Build up confidence that you can keep fit and exercise your muscles, and do it persistently.