Ok I just recently got a really badly malnurished Sand Gecko. I took him to the vet just yesterday cause he didn't eat for almost 2 weeks and I couldn't get him to eat with eye droppers and baby food and anything. The vet gave me this recipe to feed him till he eats on his own.

6oz cat food
6oz ensure (sold at gorcery stores its a weight gainer)
1 tablespoon protein powder.

I used a blender to mix it to a yogurt like subsatance. U need a syringe and have to get the tip in his mouth very gently don't hurt his mouth it's very easy so be gentle as possiable. U have to keep the mixture in the fridge. and s u c k it up in the syringe and run it under hot water to warm it up. Remember if he is mallnursihed bad enough u could kill him by giving him to much nutrtion. So give him little amounts at first and graduly rasie up the amount. Feed him 2 times daily for about 3 or 4 days then 3 times a day with about double what u were using 3 times a day then twice a day with a little bit more then that untill he eats on his own. Also make sure he is well hydrated spray water on him for about 5-10 mins make sure he is licking it off his face. He should be alright as long as u don't rush him to much and make sure he is at the right temp to it can screw his digestion up if his home isn't the right temp.