Drinking water at night will not gain weight, you can drink water in moderation at night.
Water does not have fat, carbohydrates, proteins and other substances with calories, just drinking water at night does not gain weight. However, drinking too much water at night is prone to water and sodium retention, and the body is prone to edema when you get up the next day.
It is recommended that adults can drink 1500 to 1700 milliliters of water per day under mild climate conditions, and can reasonably arrange the time of the day to drink water, and adopt the way of drinking water in small amounts and many times. When you feel thirsty at night, you can drink a moderate amount of water, but do not drink too much at once.
In addition to drinking water at night, you also need to have a balanced diet and eat a balanced diet to maintain your weight within the normal range.