Some cats become overeaters because they are taken away from their moms at too young an age.

Some cats become overeaters because they have spent some time as a stray, out on the streets, fending for themselves, and they just can't believe that food will always be there now that they have homes.

Some cats become overweight because their humans overfeed them, give them treats which are high in fat content.

Some cats become overweight because of the commercial foods they are fed, which are low on nutrients (like human fast foods).

Some cats become overweight because they get bored, being indoors with no toys, no other cat, no exercise. Left alone for long periods of time while the humans are out at work, the gym, etc.

Some cats become overweight because they are predisposed to, like humans.

Just like people, there are lots of reasons for cats to be overweight. I have a friend whose cat looks like she swallowed a basketball. I kept trying to convince this woman to cut back what she was feeding the cat. She insisted the cat was not getting too much food. She moved, got a new vet, and he laid down the law. Feed the cat this much of this type of food, and NO MORE. No matter WHAT antics the cat comes up with to bribe you. In 6 months, that kitty has lost 5.5 pounds. She still needs to lose 8 or 9 more. I don't know why this vet, at this time, got through to this friend of mine; but her cat is definitely doing MUCH better.

As for exercise, that is more difficult with cats than with dogs. Depending on age, cats sleep 15 to 18 hours out of 24. Taking the cat out for a walk or run - even if the cat is harness trained - is not really an option. They need 3 to 10 minutes playtimes with owner, morning and evening. I try to do this with a toy which they can't have unless they are supervised. Like feathers on a stick. They can't have this alone, as they might eat the feathers, and that is NOT good.) Other times, I have cat climbers, perches, and lots of toys lying about. The place sometimes looks like a playschool, ha ha.

If you look in pet stores and department stores, you will see "new kitty" packages, which contain a small litter box, maybe a liner, maybe a small bag of litter, litter scoop, water and food bowl. NO TOYS!!! Certainly NO CLIMBING tree! People who don't know think they have ALL they need with the starter kit.

As I now have 7 cats ranging from 1 to 15 years, everyone seems to get plenty of exercise. One year olds tend to get everyone moving, where they want to or not!

I hope this gives you a bit of info you were looking for.
Sandra