I have an inactive, overweight cat (14lbs), too, who is currently on 1/2 cup of Innova EVO dry food per day. I can tell you, she has remained overweight since I switched her to it a year ago. There are 612kcal/cup, so this dry food is not good for weight loss, since you would have to feed her too little food in order for your cat to lose weight.
On the other hand, the canned EVO is much less in calories--217kcal per 5.5oz can. Feeding the canned wet food would help with the weight loss. From my recent readings on the internet, 1/2 can am and 1/2 can pm of a 5.5oz can would facilitate weight loss if your cat weighs close to mine.
I also had her on the Wellness dry food, and she lost no weight on that either; I believe it has 449kcal/cup. I've tried Newman's Own dry cat food with the same result.
Years ago, I also tried a grainless raw diet and that did not work either.
I am either going to try the Innova Cat Lite or Cat dry food, the Evo, Cat, or Cat Lite wet food, and/or a combo of the dry & wet. I'm still researching the best way to get her calories, without overloading on the fiber/grains. I read somewhere that overweight cats should only get 100-150 kcal per day to lose weight, and then they should be switched to a maintenance diet once they reach their optimum weight level. It seems like the Cat Lite would be the way to go (as long as your cat has no issues with rice & barley), since you would still be able to feed your cat an acceptable volume of food.
There is a lot of confusing and contradicting info out there on cat nutrition. Some people suggest cats should only be on all wet food because cats need water in their diet via food, and to justify this claim, they suggest that cats naturally, rarely drink water, which I find to be a ridiculous statement; cats must drink water to survive, too. I can see that if you have an inactive, indoor cat that does not drink enough water (I'm sure living in a temperate-regulated environment can be a causative factor, too), you should seriously consider the possibility of feeding an all wet diet. My cat actually drinks quite a bit of water, and loves to drink from her petmate fresh flow water fountain, so I don't have to worry about her getting enough water via her food.
Anyway, I like to take the common-sense approach: feed a high-quality product with high quality ingredients and feed it in a way that meets your cat's specific needs. I adopted an older dog from a shelter a year ago, who was probably on Pedigree or some other similar food, and her coat was very dull and she had tons of dandruff. For the last year, I have had her on Innova Adult dry and her coat improved tons.
Best of luck!