Hello Anon poster Science Diet Lite is too light in protein and fat for ferrets. If you must have your ferret loose weight, please use a mix with the lite of regular Sci Diet, or use a cat food with less fat but higher protein - for Example Dad's Gourmet has 35% protein and 15% fat. Lower fat but the protein is right. Pam and her Pet Pals P.S. More EXERCISE is really the best way to loose weight - I highly recommend The Cat Dancer for cats - it comes with a stick on paw to mount to a wall or door and the cats can play with it when I'm not there to entertain them. They are fairly inexpensive too. [Posted in FML issue 1173]