Turns out none of them work. At least that's how I read the articles I keep coming across. Acai berry is a fad that not only doesn't work but is in the middle of some serious lawsuits and scams. Diet drug Meridia increases the risk of heart attack and stroke - neither of which are good for you!
What does work? Good ol' exercise and a healthy diet. Now I know there's a lot of debate over what constitutes a good diet, but we can all agree that cutting out candy and fast food might be a good place to start. A recent study says exercise can also counter the genetic tendency to carry extra weight.
Just a little food for thought.