My knowledge of Weight Watchers is skimpy at this point, although I still have my "lifetime member" pin from the 70s. Needless to say, it's way different now.
You can lose weight on any diet. ANY diet. The question is, will you be able to continue that "diet" as a lifestyle for the rest of your life so you will never, never regain that weight you don't want. If you practice Weight Watchers conscientiously, or Low-carbohydrate, or any number of other diets that cause you to lose weight,
and then stay with it, you're good to go. It's a matter of personal choice.
I like low-carb because:
--I don't have to count anything. My basic rule: No sugar. No starch. Real food.
--I don't have to pay for anything except the food I choose.
--When I reach a comfortable, healthy weight, I'm already eating the way I enjoy eating, and I'll be able to maintain it.
--Low-carb eating diminishes or eliminates hunger, especially in the early days. This eliminates the desire to snack, overeat, and constantly think about food. If you have food "addictions" (sugar especially) they will go away.
--Low-carb eating includes healthy fats like butter, bacon, olive oil, and full-fat dairy (cheese, yogurt, etc.) without "penalty" points.
With Weight Watchers, the less you weigh, the fewer points you can eat. This seems like the opposite of a reward for good behavior.
With low-carb, you are eating to a level of comfort, not calories, every step of the way.
Weight Watchers is all about paying someone else for advice and choices you can figure out for yourself. For some people, that's motivating. For me, that's EXPENSIVE.
Check out dietdoctor.com for a different (free) approach to healthy eating.
You choose!
Best wishes.