There is a lot of false information that goes into the ads that people see on television. In particular, there is the fact that celebrities, and Hudson is no exception, have personal trainers, and work in a lot of stressful situations that will change their weight and health in very drastic ways.
Jennifer Hudson did not lose weight strictly by using the Weight Watchers program. I think these programs get the celebrities who are already committed to losing weight to endorse their products. I think a lot more goes into it then they seem to let on. I do not think she lost as much as they claim she did.
The weight watchers program, although inclusive of fitness and nutritional information, is more of a plan of action which encompasses a healthy diet and exercise. While she may have continued to eat the foods she like using the weight watchers system, I would not be surprised if she also had a personal trainer to assist in her weight loss.
I have my doubts Jennifer Hudson lost weight strictly by using the Weight Watchers program. As a celebrity she probably had access to a trainer and a dietician, maybe even a coach. I think celebrities often have the opportunity to seek out individuals to help them in this manner where the regular public does not.
I think the Weight Watchers program did contribute a great deal to Jennifer Hudson's weight loss I also think she probably did other things that were not in the program such as extra exercising or eating certain foods only that helped her lose weight in addition to the Weight Watchers program.