Let's just say that whether you are losing weight or not, people's weight will fluctuate within 1 day. According to your basic weight, the weight within plus or minus 10% is normal. If you say that your 3 kg of meat is fat, that is to say, you have to eat basal metabolism +3500 calories every day for three days, ensuring 1 day. 5000 calories is impossible, unless you are a foreigner's diet or a professional physical fitness coach, but obviously you are neither, so your weight gain is not because you gain weight. As for what causes weight gain, you don't have to worry about it, because in many cases you can't solve it, so you don't need to care too much. Then deal with the problem yourself, 1, keep the stool unobstructed, 2, eat less salt and eat more.