Extreme diets pose significant health risks including nutrient deficiencies, metabolic disruptions, and adverse emotional effects. Such diets often promote unsustainable practices that can lead to yo-yo dieting, where weight fluctuates drastically. This can create a pattern of unhealthy eating behaviors and disordered eating habits. Additionally, extreme calorie restriction can weaken the immune system and lead to decreased energy levels, diminishing the body's ability to function optimally. Balance and moderation in diet are key to long-term health and well-being.