Because weight can't reflect your current real situation, for example, some people find that they have gained weight at the beginning of fitness, probably because glycogen in their bodies has increased. Because I have been inactive for a long time before, when I suddenly start exercising, the glycogen and water in my body will increase relatively. Because the energy of the body is constantly consumed at this time, the body needs more sugar and water than before, and the stored water is about three times as much as before, so the weight gain is also the increase of glycogen and water.
Don't worry about this at all. Stick to it, the body's water will be discharged, and the weight will naturally drop. The second point is that the content of muscle tissue will increase. Fat will be consumed during exercise, so that skeletal muscles can be exercised. During exercise, the density of skeletal muscles may increase, so the bones will become heavier and stronger. After the bones become heavier, the weight will naturally increase, but this increase has many benefits to the body. The enhancement of bone density can make us better exercise and fitness in the future.
So don't worry too much about either situation. As mentioned above, when you start to lose weight, don't pay too much attention to your weight, but pay more attention to your body circumference changes. Body circumference can reflect the current fitness effect more intuitively, so there is no need to worry too much about gaining weight in the short term.