Is it normal for body weight to differ by about 5–6 pounds between morning and evening?

Under normal circumstances, a weight difference of about 2.5 to 3 kilograms (5–6 jin) between morning and evening is considered normal, primarily related to factors such as body fluid levels and food metabolism. However, whether this variation is abnormal should be assessed in conjunction with daily physical condition. The specific analysis is as follows:

Human body weight naturally fluctuates throughout the day. Morning weight is typically lower, and after eating and drinking during the day, weight gradually increases, reaching its peak in the evening. The intake of food and fluids, along with retained feces and urine not yet excreted, are the main causes of this weight difference. If you drink more water, consume salty foods, or eat larger meals on a given day, the weight difference may become more pronounced. These situations fall within the range of normal physiological fluctuations and usually do not cause discomfort.

However, if the weight difference is accompanied by symptoms such as edema, fatigue, or abnormal urination, it could indicate issues related to metabolism or kidney function, which require closer attention. When monitoring weight regularly, it's recommended to measure at the same time each day using the same scale to avoid inaccuracies caused by varying measurement conditions.

As long as no other abnormal symptoms are present, a 2.5 to 3-kilogram (5–6 jin) difference in weight between morning and evening does not warrant excessive concern. Maintaining regular weight monitoring and healthy lifestyle habits can help ensure normal metabolic function.