The Weight Loss program is "Take Shape for Life", the most successful one in the Medifast Weight Loss system. This particular program also involves changing the lifestyle habits that helped get you overweight, not just losing the weight itself. Medifast has been around for more than 25 years and over 20,000 Medical doctors have recommended it to patients. Controlled studies have demonstrated a higher amount of weight loss with Medifast than Jenny Craig, Slimfast or Weight Watchers. The system is effective because it has you eating something every two and a half to three hours whenever you are awake. It keeps your body burning calories. After the first 3 days, you begin to burn fat.