I had a cat that came down with Fatty Liver Syndrome and I had to feed her nothing but baby food for 2 months straight (BTW, she recovered and lived another 14 years).
Anyway, in terms of straight meat products, Gerber sells Chicken, Turkey, Beef and Ham (all labeled as "with gravy", and they come in glass jars). The leanest is actually the Beef, and the Chicken has the most fat, at 20%. (That's important to know when dealing with fatty liver, but may not be for your cat's issue.) They are all pretty low in sodium, but your vet may advise one type over the others. My vet had me give the straight meat formulas only, nothing with veggie mix-ins. What I found is that I had to give it by syringe for the first week or so, then she got to the point of eating it on her own from a dish, but my cat was VERY ill, and yours doesn't sound quite so off her feed.
The absolute best way to get this paste food (esp. w/ liquid med) into a refusing cat, IME, is a dental irrigation syringe w/ a curved tip. Cut the tip off a bit further in (maybe 1/4") to make the hole larger , and file it down a bit to make sure there is no sharp edge on the tip, and put the goop into the syringe. Then sit on the floor with your legs straight out and wrap the cat in a LARGE towel so that only her head is sticking out, then put a second towel on top of that one and sit on the ends to hold it down. It's harder for a cat to get away by jumping up/forward than by backing up and twisting down, so back her (in her towel burrito) in between your legs so she can't back away from you, and hold her head with your thumb and index finger right behind the jaw, like the vet does. That way you have the best shot of using your other hand to get the tip of the syringe into the corner of her mouth. Squirt a bit, then set the syringe down, close her mouth and softly massage her throat to make her swallow it. (If it comes to this, best of luck; because there are few chores more difficult than getting a cat to swallow a liquid substance that it does not want.)