way too finicky, need to gain weight

My two senior cats have gotten way too fenicky. Snickers used to way a healthy 10 pounds. Natasha was at 8 pounds. Now they weigh 8 and 6 lbs respectfully. I have tried all different an foods from expensive to cheap. I have used all the tips. They act hungery, w ill walk upp to it and smell it. Then they will either go nibble on it or walk away. I have thrown more away then they eat. I keep them away from the three year old.
Snickers has kidney disease. Both cats hate the kidney food. They are active during the night.
The vet wants me toputweight on them. I have left food out for them and the opposite. Nothing works. Please help.


Thanks
Jazzmine

Unfortunately the picky behavior kind of goes with kidney disease.  It is frustrating especially all of the food being thrown away.  Have you tried a probiotic called Fortiflora sprinkled on their food?  It's not very good as a probiotic but it has animal digest in it and most kitties really like it.  Animal digest is what some pet food companies spray on their kibble to make it so appetizing for kitties.

It's odd that BOTH of them are losing at the same rate.  Does Natasha also have kidney disease?  when was the last time they had they blood valued run? 

I have a kidney cat, and took her in last week for her (now) quarterly visit and was absolutely shocked to discover she has lost more weight because over the past month she has eaten more per day than over the past year.  I'm still in shock over it and just don't get it.  But I know EXACTLY where you're coming from, because I've experienced that running over to the food dish in anticipation, then sniffing it and walking away .   It's so disappointing, AND frustrating at the same time.   You would think if they were that hungry, they would eat

When you say you keep them away from the three year old...are you talking about another CAT, or a toddler?  If another CAT, will that one eat the leftover food?  In our household, at least we have other cats that i can feed the uneaten food too, IF it's a good quality.  Sometimes I resort of even buying a lesser quality for my kidney cat, just because those are often the lower phosphorus foods. 

So, back to lack of hungry but not eating.  If you have not taken them for a recent Vet visit, first I would rule out any other health issue than the kidney disease.  Next I would think about it possibly being a nausea issue, which is also very common in kidney cats.  Are they, or at least Snickers, on an anti-emetic, or at least an ant-acid, like Pepcid A/C?  Are you familiar with this website?  http://www.felinecrf.org/nausea_vomiting_stomach_acid.htm  This is my "go to" for anything kidney related.    BTW, my Callie is on an appetite enhancer ever other day, and also an ant-acid every other day, plus sub-q fluids. 

So, I am probably the last person on earth to give tips on how to get a cat to gain weight, since I that I was doing a great job of it, and my Callie lost instead of gained .  But here are some tips that are supposed to work, of course, all this is based on the fact that you can get them to EAT:

1)  add digestive enzymes to their food  (I do this) 

2)  add an egg yolk to their food once in awhile (cooked or not, doesn't matter, but high in phosphorus for kidney cats).  Some cats will eat this, some won't.  If you cook it, it's ok to give them the entire egg, and the eggwhites will help offset the phos. in the yolk.  Maybe they would eat a scrambled egg in a little butter?  (NO salt though)  If given raw, probably split a yolk between them and mix with a little water, then mix into some food.  (I don't do this as Callie won't eat it)

3)  Freeze dried meats like Wholelife or Purebites as treats.  These can also be used as toppers if you crush them on top of food.  As treats they add some calories I do this..sometimes she eats them, sometimes she doesn't - she USED to love them though)

4)  High calorie food like Hounds and Gatos or Solid Gold.  Calories vary vastly from one food to the other.  For instance, Weruva, a favorite on this site, only has around 18 calories per ounce, and Wellness Core has around 38 cals per ounce.  See the difference?  HUGE!   Of course, I'm taking ONE Weruva and One Wellness Core Sample to look at.  Each one is slightly different, but you get the idea.  (I DO try to feed the highest calorie food I can find - this is why I am still in shock about Callie losing weight...she has been eating the very Wellness Core I used in my example)

Do you slightly warm their food?  Sometimes that helps, along with the FortiFlora Denice mentioned above.  Or the use of another crushed treat that they might like sprinkled on top. 

Check out that website I referenced.  They have all kinds of tips too, on how to get a cat to eat.