Is there a rule of thumb to go by for a kibble to canned ratio? For 6 years Charlie's been eating 1/2 cup of kibble a day sprinkled with some boiled skinless white meat chicken and has maintained a perfect weight (he gets 1/4 cup in the a.m. and 1/4 cup in the evening). He had his surgery last Monday and his surgeon said he can only eat canned food for 2 weeks post surgery to allow his gums to heal. It's been a week now that I've been feeding him canned and he seems to have lost some weight so I'm worried I'm not feeding him enough. The canned feeding instructions say 1/2 can for his weight but that seems like way too much (he weighs 11.5 lbs). Because of his back problems I don't want him gaining weight either...any suggestions?