Hai I've heard a lot about positive aspects of neutering like better personality and health but something tells me it's just one side of the coin. Are there any negative aspects of neutering cats and dogs?
There doesn't seem to be much information about it.
I've never heard of any. Neutering can save lives, can prevent prostate and bladder cancer, etc.
How about obesity?
If obesity occurs that means you have been feeding the wrong food to begin with (which would eventually cause kidney stones or bladder problems even if the dog isn't neutered) . If your dog is on a healthy diet and eating the right amounts there should be no changes in his weight and he will stay healthy. Besides that issue which as I said could cause problems even if he wasn't neutered there aren't any other things I can think of. Most of the things people say about neutering are myth's like "The dog will be sad and won't feel manly anymore" "The dog will become lazy and fat" etc which are wrong and usually don't even make sense.
Oh I have a question about the topic too. I don't know if it is true but I've heard non neutered animals intuitively know how much they should eat and when they should stop while neutered pets should be put on a strict feeding schedule because if you leave a food bowl full at all times they'll just keep eating whenever they have a chance to and this is the most common cause of obesity. I don't know if it makes sense. What do you think?

Thanks in advance.
In nature dogs and cats never know when the next meal will be, for that reason they will eat every time they see food that's why they will always seem hungry neutered or not.

Dogs need to eat good quality healthy food in specific amounts a day divided into meals (depending on age, size, breed etc). Any dog will eat uncontrollably if given the opportunity because they never know when the next meal will be, that is why dividing into meals in specific times every day may also help. As for cats they are pretty much the same but it is easier to free feed them because they tend to eat smaller amounts at a time and "save for later" if that makes sense (kind of how a lion will save the rest of his meal for later if he had enough, also because felines tend to stay in the same place while canines will travel to different places where they won't always find food), so giving them one amount in their bowl for the whole day and they will "save for later" and eat in small amounts throughout the day.

This also depends on what the animal is eating, free feeding probably won't work as well with regular commercial food, most dry food company's try to cover up the bad quality of the food by filling it with ingredients that give it good smell and taste, which then causes the animal to overfeed just because it is tasty, so of course people will think a. it's good quality food because the animal likes it b.the animal is hungry when in fact they are just eating it because it is tasty.

Think about us humans, we probably wont overfeed in dinner because it's just food, but we might overfeed sweet or salty foods because they are tasty, same with animals it's just like feeding treats. This may not be the best example because our food is so tasty that it's easy to overfeed, but think about healthy foods that are not as attractive but are important health wise.

all those ingredients are also what will eventually cause obesity and kidney and bladder problems.
Thanks for your detailed reply. I figure what I heard before doesn't have much logical ground and what you said sounds much more like the truth.
Well, I have two dogs. One is neutered and the other isn't. The neutered dog is very much overweight, while the intact dog is the perfect weight. I can't explain it.