Yes, but I had a cat which was obese...maybe about 25 lbs. He had a thyroid problem which was the underlying cause of his weight problem. We didn't know this at first, and the food maybe got him down to 19 lbs or so, still obese. He ended up dying at age 14 due to a fatty liver. If you have not already, I would recommend looking for underlying causes like thyroid or else the food will not help very much. Good luck

yes!! otherwise the vet wouldn't have recommend it.

Science Diet isn't the best food. Vets recommend it b/c they get a kickback for recommending it. I'd go with somehting that has "Light" or Healthy Weight. Wellness or Nutro Max cat. My cat also had a thyroid problem and he weighed about 20lbs or so too! Crazy! Good luck

You might get some ideas by going to: http://www.littlebigcat.com and reading Dr. Jean Hovfe's article titled "The Right Weight Loss Program for Cats" and some of her other articles on feline nutrition.
Another site on the importance of meat protein in cat diets is: http://catinfo.org The material there is also from a veterinarian.

Yes it is good food, and no vets do not get kickbacks from recommending it. That is one thing Hills Science Diet can not be accused of! They will not even give discounted food or free bags to employees including vets. I know, I have tried. Hills M/D is also a good diet if R/D does not work for him. It is sort of like the cat Adkins diet. Good luck!