I understand what you're going through. I weighed my cats yesterday and My cat Spotty is 17 pounds and Rosie is 14 pounds. By the way you don't want your cats to be too skinny or too fat. You want them to be just right.
My cat Spotty is a kibble junkie too. Rosie has been eating mostly wet but I believe she has gained weight from finishing up Spotty's wet food and perhaps the raw diet that I've been feeding Rosie might have too much fat in it so I may have to substitute 50% white meat instead of feeding all dark, though I'm aware that cats certainly do need some animal fat. Well I'm guessing you're not a raw feeder so this is probably irrelevant to you. I also feed commercial cat food too.
A while back I had switched to Innova Evo because I thought the low-carb nature of the food could help my cat Spotty lose weight. I was wrong. It made him gain weight because Evo has 612 calories per cup and is very rich for a cat with lower energy requirements.
So I concluded that with weight management for a cat you have to take 2 things into account. Excess carbohydrates is one thing but more importantly calories and exercise. Canned cat food is best for weight management because of it's high water content and high protein content which will fill your cat up on few calories and canned food is very low in carbohydrates. For the cat that must eat kibble like my Spotty, the best choice would be a food with the highest protein and the least amount of calories per cup. Right now I am trying out Royal Canin Beauty and Fit which has 37% protein, 15% fat(according to the print on the bag but on the website it says 9% so I need to talk to them about that error) and 8% fiber. fiber is filling and helps with hairballs. The food has 339 calories per cup, a huge reduction from Evo's 612 calories per cup. I decided to try this for a while and see if it helps my cats lose weight and in the meantime I have to watch out for Rosie eating Spotty's wet food.
The California Natural has a reasonable calorie content too. $398 calories per cup, 36% protein, 16% fat but my cats gained weight on this food too. I must have fed too much. So I'll think I'll stick with the Royal Canin Beauty and Fit for now which has fewer calories than California Natural and then after my cats have trimmed down and they're ready for the maintenance phase I might switch back to California Natural, maybe.
Dry food in general is more fattening than wet so if you can, try to feed as much wet food as your cat is willing to eat and limit dry food. And expect slow weight loss results. Too fast is not healthy for the cat. Good luck.
Oh, and play with your cat as much as you can for exercise.