cat lost a lot of weight, trying to "fatten" him up

Our Kenji lost a lot of weight. He had full blood work-everything fine. He was eating pate then got real picky and refused to eat it. We had his teeth cleaned yesterday, he has been eating Merricks outdoor cuts in gravy but still chews to the side sometimes. He has eaten 3 packages since yesterday. I don't know if he is getting enough calories and I would like to find something similar that is more economical any suggestions please

My older cat (12 yrs) has gotten very picky, and was losing weight--what seemed like a lot to me, so off to the vet we went.  The vet declared him (after a few hundred $ worth of tests) healthy, so I just started opening can after can to see what he would eat.  He seems to be enjoying the fancy feast pates, the meow mix plastic cup-type dinners, and Friskies pates.  I try to keep him off the fishy ones though, and stick to the beef, turkey and giblets, and chicken feast ones.  I had a thread on here somewhere under nutrition because I was worried about the fancy feast not being very good, but everyone said it is fine. 

After my cats get their teeth cleaned I think their mouth is sore for a couple of days.  I've noticed them eating carefully after getting theirs cleaned before, then they go back to normal after a few days.  It might just be sore to him.  Shortstack love-love-loves the Merrick wet foods, but it was getting really expensive, so he gets fancy feast now too.

Oh, wanted to mention about calories---we had a very elderly female (19 years) we had to have put to sleep about a month ago (due to multiple health problems and her quality of life was gone--we are still sad over it, very sad).  She was losing weight and going to skin and bones, and for calories we put her on Hill's A/D for a while.  She gained weight quickly.  I think it is a very high calorie acute care formula for very sick cats, you might ask about it at the vet.  It's prescription and it was about $30 for a case, but it worked well to put weight on her.  Warning--it stinks!!!  But they love it, she ate it very well and my others smelled it and threw a fit wanting it too.

Thank you for your input! I just got him some Friskies prime filets which isn't the best but he did scarf it down. Unless one spends a lot most likely not going to be very healthy. I tried the loaf in 13 oz can 2 weeks ago of a healthier brand  which was fairly economical but the cats being grazers I landed up throwing some out especially with Kenji eating less. Anyway wet is supposed to be better for them no matter what because of the low moisture content in the dry.

Well, I thought the FF wouldn't be good for them too, but it is one of the better reasonably priced wet foods.  Look under the nutrition forums, there are threads about the various grocery store brands.  Some of the more expensive brands are really bad too, when I thought they would be really good.  I had a thread on the nutrition forums that people wrote a lot about some of the higher-price brands being really bad.  A lot of the expensive brands are full of grains and fillers.

My cats eat only wet, with dry only as a "snack" during the day in limited amounts.  I have tried nearly all the expensive brands, but they will refuse most of them, but gobble the fancy feast and the friskies.  I say if you kitty needs weight, feed him whatever he will eat until he gets built back up.  The prescription A/D really packed some weight on our old girl, if all else fails, buy some of that at the vet's.  Good luck!  Cats are weirder than people about their food it seems!!

Years ago one of my seniors got sick and quit eating his dry food at all.  Before this happened he would never touch wet food no matter what I tried.  I took him to the vet and they ran tests and did blood work but never figured out what was going on.  I gave him Fancy Feat Classics Pate and he gobbled the entire can.  I was able to use this to get him to gain back a large chunk of the wait he lost.  The best answer my vet at that time could come up was he stopped eating do to nausea.  He gave Claude an injection and told me to wait a few hours and try feeding him a small meal of wet food.  Once he started eating the  Fancy Feast he was given two cans a day.  I have other cats so they always have access to dry food too,  He never went back to eating dry food.  I was very lucky that one of my friends who is really not a cat person stepped up and offered to feed Claude in the morning when we had to travel. My regular cat sitter was working at a job that had a long commute at that time and could not come over in the morning. He took over the morning feeding and they communicated by phone to establish a consistent feeding schedule while we were out of town,  If my friend had not been able to help I would have had to take my senior cat who hated car rides and the carrier to my parent's house instead.  We had to go out of town unexpectedly for a funeral for my hubby's family.

He originally lost a lot of the weight because he was throwing up most of his food. His urinalysis came back good yesterday and he is eating ok. I wish he would eat more but he is somewhat inactive which is closer to his normal self. Hopefully that will help him by him not burning too many calories.

Kenji brown one on left passed this morning. Here he is with his little sister Missi in 2014. I am rather heartbroken.

Of course you are devastated. Kenji was a part of your family, had a secure place in your heart.

We take them on, love them so very much, and try to ignore the fact that we will live longer than they will. And when they go it is a crushing loss.

Go free over the Rainbow Bridge, handsome Kenji, beautiful boy. Wait with all the other beloved pets, and one day, some day, you will reunite with your family who have always loved you.

I am so sorry for your loss. I know that deep pain. I'll keep you in my thoughts and prayers.