This weight loss method of eating only apples on the first day and drinking only milk on the second day is actually the evolution of a single weight loss method.
Although the weight will drop rapidly in the short term, with this method, it will rebound as soon as you return to a normal diet.
The principle of eating only certain foods a day to lose weight is to reduce the intake of salt to cause dehydration of the body, thereby reducing weight.
It will cause nutritional imbalance and the consequences will be damage to your vitality. Because you only eat apples on the first day and the protein intake is insufficient, it will cause anorexia, mental depression, etc. By the way, the death of anorexia will be mentioned here. The rate is second only to cancer. Moreover, with such a diet, once you return to a normal diet, you will immediately regain weight.
This single food diet will harm your health due to lack of nutrients, and may even lead to a crisis of immune disorders.