May I suggest the South Beach Diet. My loss has been 30 lbs in less than 11 weeks. It is not really much different than the old Weight Watchers, except that you don't have to obsess over weighing, measuring, exchanges, and points. And it allows enough carbs to keep the elimination system functioning. After the first 2 weeks, it is easy to follow, and you can order off of most restaurant menues. I feel great.
South Beach is without question the healthiest diet out there. The basic theory revolves around good fats, bad fats, good carbs, bad carbs. Sugar is a big no no, but Splenda works fine.
I quickly dropped 25 lbs. over two years ago and have not gained a pound since. I'm 65, nearly 6 ft with a 33" waist. I'm fanatical about always following the South Beach principles of eating.
The Doc that developed the diet is a cardiologist that originally designed the plan as a healthy way of eating for his heart patients. But everyone that followed it lost weight and he took it from there.