Getting her to eat more

My 14 & 1/2 year old cat saw the vet last week, she is a little underweight (blood work was good).  The vet suggested I increase her food to about 1 & 1/2 to 2  of the 5.5oz cans per day.  I am trying to do that however I can't get her to eat more than about 1/2 to 3/4 can per feeding.  I work 10 hour days so it's hard for me to feed her more than about twice a day.  Any ideas on how to get her to eat more?  Right now what she doesn't finish I give her at the next feeding, I am also warming any food that comes from the fridge.  I also give her some right before I go to bed.  Is there a canned food that has more calories so she won't have to eat as much to get the same nutrition if that makes sense.  The food I am feeding her now has about 150 calories per can (I think)

wellness canned chicken has about 170 calories per can. have you tried feeding her dry food? or raw?

I prefer to stay away from dry as I had a vet tell me her kidneys are smaller than they should be, and personally I feel that wet is best for cats.  I have tried to convert to raw as that's what I feed my dog, but I haven't had good success with the kitties.

I use fried dried raw and mix it with canned food, I don't add any water like it says too, just use the juice from the canned to coat it. the can has 168 calories and the freeze dried has 208 per cup in one brand and 130 in another, guess it just depends on the type of meat they use. but if your cat just likes the canned, get Wellness brand, they have high calorie flavors and are grain free

If you can get her to eat egg yolks, they are full of calories and nutrients.  If she isn't fond of them (and you can offer them either cooked or raw), try mixing them in her canned food.  You could start with a small amount at a time and work your way up. 

One or two egg yolks a week would be good.  One person feeding raw actually had to stop feeding them because her cats were gaining to much weight on them!