Weakness without eating should be considered as a result of malnutrition, hypoglycemia, hyponatremia, hypokalemia and other causes. 1. Malnutrition: not eating so that the human body can not take in enough nutrients to cause related diseases, such as the lack of vitamin D prone to rickets, the lack of iron easily caused by anemia, etc., long-term intake of protein, insufficient energy, but also cause weight loss, memory loss, dizziness, fatigue and so on. 2. Hypoglycemia: Insufficient supply of energy without eating. It will cause hypoglycemia, hypoglycemia will appear generalized weakness, and there will also be symptoms such as profuse sweating. 3. Hyponatremia: frequent skipping meals can lead to insufficient sodium intake, causing hyponatremia, which can also lead to symptoms of fatigue. 4. Hypokalemia: Insufficient intake of potassium, prolonged skipping meals or eating less can cause potassium deficiency, and low blood potassium can lead to fatigue. Not eating for a long time will affect your health, so it is recommended to have a regular diet, and if you have any uncomfortable symptoms, it is recommended to consult a doctor in time.