What if alli doesn't work? I've seen statistics that say that a certain percentage of people experience a certain percentage of additional weight loss. Why do some people get more benefit from it than others?

Nobodies body or diet is the exact same. So, the chemicals probably react differently in everyone's body. Plus, some people are doing other things to lose weight when they take Alli, such as diet, exercise, and so on. This is especially true since taking Alli causes a lot of people to drastically reduce their fat intake. Those who reduce their fat intake more than others probably also lose more weight than others.

Maybe people who have a sweet tooth and get most of their fattening calories from sugar don't benefit as much, either.