The “yo-yo” effect — sometimes called “weight cycling” — happens when people cut their calorie intake, lose a substantial amount of weight but eventually gain it all back. In fact, it’s common for yo-yo dieters to gain back even more weight than they lost.
There are different causes for the yo-yo effect. In many cases, people hoping for rapid weight loss cut their calories too drastically with extreme diet plans and, in the end, hunger and cravings win out.
Another common scenario: Many people reduce their calories without doing even moderate exercise. Without activity, the body tends to lose not only fat but lean muscle mass. Your body will become less efficient at burning energy and you will not be able to lose weight.