The weakness after hunger is usually caused by endocrine diseases, and there are four major causes of common endocrine diseases: First, periodic hypokalemia is common, such as hypokalemia with symptoms of peripheral weakness, insufficient blood supply to the heart muscle, arrhythmia, dizziness with nausea and regurgitation, etc. At this time, if you eat in time or eat fruits and drinks containing more potassium ions, such as bananas and oranges, it will relieve the symptoms. Secondly, hypoglycemic reaction will produce weakness after hunger, accompanied by heavy sweating, chest tightness, shortness of breath, palpitations, arrhythmia and other symptoms. Third, common diseases such as coronary heart disease, myocarditis, cardiomyopathy resulting in insufficient blood supply to the coronary arteries of the heart will also produce symptoms of weakness around the body due to hypoglycemic reaction after a month. Fourth, hyperthyroidism, when the patient will have an enhanced metabolism, in a high metabolic state a starvation will appear the symptoms of weakness around the body.