No, I don't think it will affect kidney stones, but.. Slim fast has horrible ingredients, and I would not feed it to my dog. From their website, they list Hydrogenated soybean oil, High Fructose Corn syrup, etc. Soybean oil will make you fat, and so will high fructose corn syrup.Suffice to say, stay away from Slim Fast! Eat whole foods instead. At best, these drinks may cause rapid weight loss, but they are not healthy and usually the weight comes back later.