Congrats on wanting to feed your kitty a better diet!
When navigating feline food, it can be really difficult, and our vets often aren't able to help us much. Most of them have little nutritional training, and the information out there is just overwhelming.
A place to begin is learning a little bit about what's good and bad for cats. Cats are obligate carnivores. I never thought about what this meant, and I fed my cats a prescription kibble diet for many years. But when we rescued a kitty that was a health mess, we had to start learning, because the stuff we were doing - and that our vets advised - wasn't working.
And I found out what it meant that cats are obligate carnivores. This means they need to get most of their nutrition from meat and fat - animal sources of food.
I don't know which Friskies you were feeding, but they all look pretty similar.Friskies Indoor Delights Dry ingredients: http://www.friskies.com/Cat-Food/Dry-Cat-Food/Indoor-DelightsGround yellow corn, corn gluten meal,
chicken by-product meal, meat and bone meal, soybean meal
, beef tallow preserved with mixed-tocopherols (form of Vitamin E), turkey by-product meal, powdered cellulose
, animal liver flavor, soybean hulls
, malt extract, phosphoric acid, calcium carbonate, potassium chloride, salt, choline chloride, dried cheese powder, added color (Yellow 6, Yellow 5, Red 40, Blue 2 and other color), parsley flakes, taurine, calcium phosphate, Vitamin E supplement, zinc sulfate, ferrous sulfate, niacin, manganese sulfate, Vitamin A supplement, calcium pantothenate, thiamine mononitrate, copper sulfate, riboflavin supplement, Vitamin B-12 supplement, pyridoxine hydrochloride, folic acid, Vitamin D-3 supplement, calcium iodate, biotin, menadione sodium bisulfite complex (source of Vitamin K activity), sodium selenite. D-6002Reduced Calorie Natural balance dry ingredients
Chicken Meal, Chicken, Brown Rice, Dried Potatoes, Oats, Pearled Barley, Pea Fiber, Pea Protein, Alfalfa Meal,
Salmon Meal, Chicken Fat (preserved with natural mixed tocopherols), Lamb Meal, Beet Pulp, Tomato Pomace,
Natural Flavor, Carrots, Potatoes,
Duck, Dried Egg, Brewers Dried Yeast, Salmon Oil, Salt, Potassium Chloride, Vitamins (vitamin E supplement, niacin supplement, d-calcium pantothenate, vitamin A acetate, thiamine mononitrate, pyridoxine hydrochloride, riboflavin supplement, vitamin D3 supplement, biotin, vitamin B12 supplement, folic acid), Minerals (zinc sulfate, ferrous sulfate, copper sulfate, manganous sulfate, sodium selenite, calcium iodate), Taurine, Flaxseed Meal
, Choline Chloride, Yucca Schidigera Extract, L-Carnitine, DL-Methionine, Iron Amino Acid Chelate, Manganese Amino Acid Chelate, Zinc Amino Acid Chelate, Copper Amino Acid Chelate, Mixed Tocopherols and Citric Acid (preservatives), Kelp Meal, Cranberries, Dried Parsley,
L-Lysine, Dried Spinach.
The ingredients in bold are all ingredients that cats don't need, don't utilize very well (as obligate carnivores), are actually bad for them, or are just filler.
On a dry matter basis, the Reduced calorie Natural Balance has 33% carbs and 9% fiber.
On a dry matter basis, the Friskies Indoor Delights has 42% carbs and 5% fiber.
Both foods are VERY high in carbohydrates. The problem with carbohydrates in cat foods is that cats have no dietary requirement for them. Not only this, but they do not digest them very well, and they are not easily accessible sources of energy. Cats use meat-based protein and fat for energy, and process them efficiently. When eating carbs, it just goes to fat on them, because they don't "use" the energy from carbohydrates. The problem is that it leaves them feeling hungry, so they eat more food - and they end up eating more calories than they need to in order to get enough energy from meat-based sources of protein and fat.
Human nutrition and diet requirements are VERY different than a cat's. A high fiber diet will help a person lose weight, but not a cat. Here's an article you may find interesting on the subject: "Why feeding high fiber kibble to cats defies logic" http://healthypets.mercola.com/sites/healthypets/archive/2012/05/02/fiber-rich-diets-for-overweight-cats.aspx
I think to resolve your kitty's stool, you may want to consider, as mrsgreenjeans suggested, looking for a kibble that's high protein, low-carb. There aren't many of them.
In fact, if you can afford it, and your lifestyle allows for it, you may want to consider switching your kitties - at least your fat kitty - to a wet food only diet. Here is information on that: http://www.catinfo.org
There was a study published comparing cats feed dry food and wet food. The dry food provided was the EXACT same food as the wet food, just dehydrated. The cats eating the wet food naturally ate fewer calories. This is why when someone has a kitty that needs to lose weight, so many of the first suggestions you see are to switch the kitty to wet food. Especially a grain-free low carb wet food. Even Fancy Feast (classic style only) and Friskies (pate style only) fit this bill. Those aren't very high quality foods, but they're still superior foods for your kitty than the kibble, and will probably help your big girl lose weight better than trying to fix the smell of her poop on the food she's eating.
When I have stinky poop, I can usually figure out it's from something I ate. Stinky poop is not a natural condition for a cat either. That stinky poop is a sign that her food doesn't agree with her.
I think starting with a grain-free food - whether kibble or canned - would be a good start and may agree with her better. (Not all grain free foods are low carb though. And kibble, by it's very nature, is usually high carb). The two Sally listed are about the only two that are high protein, low carb dry foods.
I recommend probiotics for ALL kitties (and people LOL). I use Natural Factors double-factor Acidophilus+Bifidus for the cats and my husband and my self. I just sprinkle the capsule on their food - they like it and eat it right up.
I don't know if it will help clear up the smell. But it's good for them.