Because relatively speaking, April will basically change from long sleeves to short sleeves, so it is easy to highlight the meat on your body, and March is a good time to lose weight, and then it will transition to summer in May and June.
That makes it easier to show the meat. In this case, appearance and figure are very important to women. If you don't lose weight, others will naturally have some opinions about yourself. The main meaning of this sentence is that if we don't lose weight in March, we may start to feel sad in April, because in April, our clothes have changed from long sleeves to short sleeves. I officially put on short sleeves in May, when passers-by saw it, they would avoid it. Of course, this is an exaggeration, but it makes sense, and then June will naturally make my boyfriend lose. Of course, this sentence mainly emphasizes the importance of figure to women, and cannot be said to be an absolute result.
So we usually try to control our body and lose weight when we should lose weight, so as to give others a better impression. Although relatively speaking, appearance is not the most important, it also gives people a more comfortable feeling.