The reason for these side effects is apparent: The inability to digest lactose triggers the fermentation of the milk in the colon. As a result, bloating, gas, and cramping occurs.
Lactose intolerance isn’t as much a dangerous health condition as it is an uncomfortable one. However, excess milk consumption can result in severe dehydration, which can become harmful and require IV fluid replacement.
Here’s an animated video describing what can happen if a cat drinks milk:
Keeping Your Cat’s Dairy Intake Under Control
Most cats will be fine drinking a few tablespoons of milk while avoiding the consequences of diarrhea or vomiting. But some feline digestive systems are far more sensitive than others. Therefore, even as an occasional treat, milk may not be an excellent snack for a kitty.
Now you might be wondering: What about milk alternatives?
Lactose intolerant humans can swap out regular cow’s milk for lactose-free almond milk, soy milk, and rice milk to keep their condition under control. However, the sugar content in these alternatives is still far too high for a cat:
- Almond Milk: 21 grams (0.74 ounce) of sugar per cup
- Soy Milk: 10 grams (0.35 ounce) of sugar per cup
- Rice Milk: 8 grams (0.28 ounce) of sugar per cup
Pouring out a bowl full of milk for your cat may quench her milk craving. Yet, it can also increase your cat’s carbohydrate intake, making it more difficult for your cat’s body to regulate her blood sugar levels while heightening your cat’s risk of developing diabetes. Additionally, there’s no guarantee your cat will even enjoy these sweet beverages — cats can’t taste sweets!
Cat-Specific Milk Alternatives
The good news is that you don’t have to stop giving your cat a milky treat altogether. Instead, you can give your cat a milk product explicitly designed for a cat’s sensitive digestive system.
Cat-Sip milk is an excellent example of this type of product.
Not only is it 99% lactose-free, but it’s also only 1% fat while including the extra benefit of taurine infusion. Your cat can successfully satisfy this milk craving without diarrhea, and you can be confident your kitty’s heart, vision, and muscles are receiving proper nourishment!
And, if you must give your cat dairy products, stick to those with lower lactose contents. Ice cream, yogurt, and maybe cheese may fare better on your cat’s sensitive GI tract, but limit how often you treat your cat to dairy either way.
Can a Cat Survive on Just Milk?
Cats can probably survive on any drink or food for a limited amount of time, but the negative health consequences will eventually catch up to your kitty. First, there’s the lactose intolerance concern. If your cat is indeed lactose intolerant, drinking nothing but milk could cause persistent diarrhea and dangerous levels of dehydration.
And while milk provides nutritional benefits to humans, this isn’t true for cats.
A cat has strict nutritional needs to stay strong and healthy. Each day, a healthy adult cat should eat between 240 and 280 calories, no more than 12.5 grams (0.44 ounce) of protein, and fewer than four grams of fat. Now, take a look at the nutritional value of one cup of milk:
- Calories: 149 calories
- Protein: 7.7 grams (0.27 ounce)
- Fat: 8 grams (0.28 ounce)
- Sugar: 12.3 grams (0.43 ounce)
If a cat were to drink nothing but milk, it would take about 1 ⅔ cups of milk daily to remain at a healthy weight. The issue here is that a cat drinking that much milk would slightly exceed their daily protein requirements and exceed their fat intake limits over three-fold.
A strict milk diet can lead a cat to develop diabetes after her body can no longer keep up with insulin production to maintain blood sugar levels. And obesity is another possible consequence, multiplying your cat’s risk of mortality by 2.8 times.
The only time a cat should drink nothing but milk is when she’s a kitten still nursing with her mother or drinking a kitten milk replacement until she weans completely.
Don’t let your cat fool you. Just because your kitty laps up a small bowl of milk and begs for more, that doesn’t mean this tasty treat is healthy for her system. Even giving your cat a tiny amount of milk, yogurt, or ice cream can give her an upset stomach or make her vomit.
Stick to feeding your cat food designed for felines — such as nutrient-dense kibble and aromatic canned food. Otherwise, the only fluid your cat needs to stay hydrated is water (particularly 200-250 mL of H2O a day).
- VCA Hospitals: Obesity in Cats
- Fetch by WebMD: Feline Diabetes: Symptoms, Treatments, Prevention, and Diet Tips
- Scientific American: Strange but True: Cats Cannot Taste Sweets
- Fetch by WebMD: Cats and Dairy: Get the Facts
- Healthline: Milk 101: Nutrition Facts and Health Effects
- National Research Council: Your Cat’s Nutritional Needs