Truthfully I'm not overly familiar with the momentum plan but I do know the filling foods list models the idea of ww's previous plan called Core which is what I follow. You'll notice the filling foods list generally has lower points and is I guess scientifically calculated to be more satisfying overall. Admittedly the filling foods list does not include cookies and ice cream but whole foods such as fruits, veggies, lean meats, low fat dairy, etc. Really it works. Once you've ditched the junkie, empty calorie foods for the filling foods your body adjusts and actually does quite well on the plan. And if you're hungry these foods usually satisfy the appetite better because you can eat more of them for the same point values of empty-caloried foods. (I hope that makes sense.)
I have followed the plan for two years and have kept of 60 pounds. I plan to reach goal weight this year which is actually another 30ish pounds. Success of the program, I believe, does lie in the conjunction of a good diet and exercise. I exercise 6 days a week.