I would feed them the food they like, but cut back the portions. So if I had a 14 pound cat eating four cans of wet food, I'd gradually cut it down to three and a half, etc.
Most cat foods have a calorie level listed. I'm not a vet, so talk to a real vet, but cats have daily calorie requirements that vary based on age and activity.
Many cat foods vary on the calorie levels, which requires you to feed a cat two cans, for example, of one brand but only one can of another. As an aside, I try to feed my cat high protein/calorie foods so they have to eat less, digest less, and poop less.
There isn't any particular brand that works for all cats. Any canned food works to help control weight. You just need to control the amount of calories the cat eats daily. You could an inexpensive big name brand or an expensive premium brand. The most important thing is that your cat will eat the food and you can afford it
You'll get a lot of different answers for your question. Some people may feed Weruva, Tiki Cat, Nature's Variety, etc for weight loss while others may feed Friskies and Fancy Feast, Trader Joe's store brand, etc. Here's a thread with suggestions on food for weight control and loss: http://www.thecatsite.com/t/265600/weight-loss-diet-canned-food-suggestions-please
Agree with all the above! As long as my cat's calories are more or less on target for the day, I don't generally stick to one type of food. I will say that I've found it's more economical to feed more calorie-dense pate-type foods than the more watery "stews" (ie: Weruva) as they contain more calories per ounce and I need to feed less of it as a result. I just reserve the stews for midday meals instead of start-of-day/end-of-day meals.