A diet that promotes drastic weight loss can be very unhealthy and could either indicate loss of water weight or muscle mass. Choosing extreme diets that promise rapid weight reduction can put your body in stress and can deprive it of essential nutrients. Rapid weight loss problems include headache, nausea, weakness, and light-headedness which are some of the adverse effects of drastic weight loss.
Rapid weight loss can also lead to electrolytes imbalance and gallstones.