How to properly change foods to avoid diarrhea or constipation

A question I often get asked is, "Help! My kitten has diarrhea (or has constipation). What should I do?" Because diarrhea and constipation are symptoms, I always urge them to take their kitten (or puppy) to a vet to make sure there's not a serious underlying issue. However, once I was made aware that the issue started after they changed the kitty's (or puppy's) food, no other symptoms were present (such as vomiting, inappetence, lethargy, fever, etc.) I could safely assume that the cause was a lack of food transition.

Now, I'm a subject matter expert in kittens, not puppies, but transitioning foods for both should be handled the same way, just with different types of food. Keep this in mind while reading. 

Kittens under one year of age are still developing, including their little digestive tract. For this reason, avoid feeding your fur babies anything with fish. Fish used in cat foods have become increasingly polluted with mercury, and mercury is a potent neurotoxin (like sticky enzymes), and a kitten's body isn't developed enough to extract it, which can cause digestive problems, kidney issues, brain damage, respiratory failure, and even death.

Feeding them the right food is important, but changing their food from an infant food (like Royal Canin's Mother/Baby Cat®️ cat food to something less fatty, maybe even more affordable) needs to be done slowly, with care. Otherwise, your little fur-baby might end up with a horrible case of diarrhea, which can quickly dehydrate them.

Until they are at least 4 months old, kittens should still be on kitten food, canned/wet, and kibble. However, switching foods will shock their digestive tract, usually causing diarrhea or constipation if not done correctly. To avoid this, assuming diarrhea or constipation started after changing foods, switch back to the other food, then do a slow transition from the previous one to the new (Note: most people don't have the caring patience to handle this properly)

What this will look like is taking a can of the previous food and mixing it with a tablespoon of the new food in a bowl. 

Add and mix a tablespoon of the new food into the bowl for every feeding, where you take out a tablespoon to feed your baby. Do this every time you feed your baby until what's in the bowl is primarily the new food (a tablespoon out = a tablespoon of new in). The same should be done when switching their dry kibble as well. 

After three days, throw away what's in the bowl. It will feel like a waste, but fight that feeling. Take comfort in knowing this will probably be the only time you'll need to toss what looks and smells like perfectly good food away. The reason is that after 48 hours of being opened, the nutrients drop considerably, and the length of time it can be left out for your baby to eat reduces as well (in a room temperature environment, wet food should be disposed of after two hours. Otherwise, nutrients diminish and rot sets in, all of which can cause diarrhea, especially in a kitten).

If diarrhea persists, take your kitten to a licensed vet as, again, they will get dehydrated quickly, which can cause organ failure and (ultimately) death. 

**Only if the vet is unable to determine the cause should this next step be tried: If the kitten is still on formula *and has no issues eating, mix in a tiny amount (if it's for more than one kitten, mix in 1/8 teaspoon) of organic, unsweetened canned pumpkin. If the kitten is on wet food, do the same, but start with 1/8 teaspoon of organic, unsweetened canned pumpkin. 

Note: If the kitten is constipated, use the same "kitten hack." Organic, unsweetened canned pumpkin is magical in its ability to work within the digestive tract.