When your body is dehydrated, it is more likely to retain water. Therefore, in order to shed excess water weight overnight, you must drink the recommended amount of water during the day.  The average man needs to drink 3 liters of water each day. The average woman needs to drink 2.2 liters of water each day.  Avoid large amounts of caffeine and alcohol since both substances can dehydrate your body. Other beverages can help you remain adequately hydrated, but you should avoid drinking too many sugary beverages or drinks that are otherwise high calories. When you consume a diet high in sodium, your body will retain water. The excess water may cause your stomach to bloat and your waist size to increase. In order to decrease your sodium intake, avoid:  Foods that taste salty. Adding salt to your food. Foods do not taste salty, but contain hidden sodium. These may include canned food, processed meats, and frozen meals. A diet high in sugar increases your body’s storage of fat. Throughout the day avoid sugary foods and beverages. These include:  Candies, sweets, and desserts Fruit juices Sodas Alcoholic beverages As your body digests carbohydrates, the each gram of carbs retains approximately 4 grams of water. Once the digestion process is complete, the body stores carbs as sugars and fats. In order to reduce the amount of water your body retains, as well as the amount of fats and sugars it stores, you can limit your intake of carbohydrates. When you go on a safe, low-carb diet, you can lose around 10 pounds of water weight. In an effort to lose weight, especially if you want to do so without developing loose skin, swap your sugary snacks or carb-loaded meals with items high in protein, fiber, and potassium.  Foods rich in protein, such as meats and legumes, promote muscle building and increase your metabolic rate. Items high in fiber, such as leafy greens and whole grains, and potassium, such as bananas and peanut butter, help your body to burn fat and lose excess water.

TL;DR in Vietnamese:
Uống nhiều nước hơn. Giảm lượng natri nạp vào. Hạn chế lượng đường nạp vào. Giảm lượng tinh bột (carb) nạp vào. Tăng lượng protein, chất xơ và kali.