Do you know for sure how many lbs in excess he has? If you work with measurements and certainty you will find it easier and better to achieve your goal of making him lose some weight. You need to be careful. Obesity in cats is dangerous but so is lack of nutrients. So, you first need to make sure where - on the scale- you want him to be at. What is your gap? A gap is your current situation vs what you want to achieve, so if you want him to lose 3 lbs then that would be your gap and you'd have to work on it. Usually, a vet will be able to determine how much weight he must lose to be healthier. I wouldn't trust myself to determine how much weight my cat needs to lose.
As to his loose stool, commercial foods can cause this as well as parasites and sudden diet change. Try to keep him on the same diet or brand. If his situation doesn't improve, take him to the vet. My cat has Inflammatory Bowel Disease, a condition which gives cats diarrhea in bloody stool. Other health conditions can cause diarrhea, and it all comes down to commercial foods, which can cause either constipation or loose stool. To get to the root of what's causing this loose stool, first keep him on the same diet, feed him the same amount every day but don't starve him. If, with all your consistency you still notice loose stool then it's time for a good check up.
Many commercial foods have the words 'Weight Management' on the label. Now, I tried this and it didn't work AT ALL. My cat was still gaining weight. The only thing that's worked for me is cooked chicken, ground beef, liver, and fish with all the extra nutrients he needs which I buy on a website. My cat now looks a bit leaner and more muscular and I noticed this 2 days ago, plus his energy levels are rocketed. You'll see if you look at my pictures how fat he was before I introduced him to his new diet. But all cats are different although they have the same needs (obligated carnivores who need fat to live).
So, I would try consistency in his diet and the amount of food (just reduce the amount of food. You'll notice that in the wild, cats don't eat every day as food source isn't always available). But feed him twice a day, less amounts, and see if anything changes. The only commercial food I would recommend is Natural Balance. I believe it is the closest to what cats find naturally, and the formula doesn't give cats diarrhea. Try it, I'm sure your cat will like it. Get canned if you will. I think it's better. You can find it at Petco, and they find it very appealing.
Don't worry about tremors (twitching) I'd say. He is just dreaming. My cats does it too.
Good Luck.
Thanks for your reply. Because I fed him too much he has been having semi loose stools and his poor rearend much be irritated because he keeps licking it. I definitely have to go to the pet store and see what to feed him. Something that will not cause the bowels this problem. It is so difficult to know what to do since I have no background info on him and he is about 3 yrs old.
I don't know about cat food choices, but you can look at the labels to see if they say no ingredients from China, etc.
As far as feeding goes, better to feed them 1/2 cup a day (2 x with 1/4) than it is to leave food out all the time. To do so, you may want to gradually reduce how much you feed your cat until you get to that amount.
As tough as it is, ignore your cat's begging if it is any other time than when normally feed him. See if you can play with him or do something that doesn't involve eating. You can also google up overweight cat and see what resources come up.