Reason #2: Yo-yo diets wreck your metabolism.
While the initial drastic weight loss may seem like the diet is working, yo-yo dieters will soon experience a 'plateau', meaning the rapid weight loss that was initially achieved begins to slow down or stop.
This plateau is the result of the adaptation of your body: With less calories coming in and less muscle mass in the body, the body reacts by going into starvation mode and starts to conserve energy. Less energy is burnt and the metabolic rate slows down, making it much more difficult to maintain your new figure.
Those struggling to maintain the diet will inevitably find their weight piling back on, sometimes more than what they started out with.