A single binge generally does not have much effect on body weight, there may be a slight weight loss, which is normal; however, the causes of weight loss after long-term overeating are mostly seen in hyperthyroidism, diabetes, gastrointestinal diseases and so on. 1. Hyperthyroidism: Hyperthyroidism is thyrotoxicosis caused by excessive secretion of thyroid hormones, resulting in increased metabolic activity. There is often hyperphagia, lethargy, palpitations and excessive sweating. So emaciation occurs after overeating. 2. Diabetes mellitus: diabetes mellitus is characterized by excessive drinking, excessive eating, excessive urination, emaciation after overeating, and a significant rise in blood sugar. 3. Gastrointestinal diseases: chronic enteritis, intestinal tuberculosis, irritable bowel syndrome, etc., a large amount of food will cause gastrointestinal burden, bloating, diarrhea, etc., affecting the digestion and absorption of food, and wasting will occur. There are other reasons for weight loss after overeating, and it is recommended to seek medical attention in time to improve the examination and cooperate with the doctor’s treatment if necessary.