On the one hand, it may be because after exercise, my appetite increased greatly and I ate more than usual, so I gained weight.

On the other hand, after exercise, the fat is reduced, but the muscles are increased. Muscle of the same volume is heavier than fat, so the weight also increases.

Suggestion: Don't drink a lot of water within half an hour after exercise, and eat less after exercise, if the exercise is in the afternoon.

Finally, after exercise, fruit is the main food. Stop eating starchy food. Drinking more water after half an hour of exercise also helps to burn fat! Come on!