Whether or not a 4 pound weight difference between morning and evening is normal needs to be seen in context. It may be that the morning weight is 4 pounds heavier than the evening weight, or it may be that the morning weight is 4 pounds lighter than the evening weight, which may be caused by diet, weight loss, disease and other factors.1. Normal: Usually, the morning weight of normal people is 2-3 pounds less than the evening weight, and occasionally there is a difference of 4 pounds, which is generally a normal phenomenon. Because the morning weight measurement is in the state of fasting, the evening is the result of the measurement after a day of food accumulation. If the morning weight is more than the evening weight 4 pounds, may be due to drink less water or this is the result of measurement during weight loss, also belongs to the normal phenomenon, because the weight loss people in the day intake of nutrients less, activity and more, so lead to more water evaporation, the night weight will be lighter; 2, abnormal: morning and evening weight difference of 4 pounds may also be due to disease factors, this situation is not normal . For example, digestive system diseases, cardiac insufficiency, chronic febrile diseases, infectious diseases and other causes, resulting in abnormal water excretion or excessive loss of water in the human body, which leads to a 4 pounds difference in weight in the morning and evening.