Why Cats Go Crazy for Milk. The Surprising Science Behind Feline Milk Lust

The Domestic Cat’s Natural Diet

Cats are obligate carnivores whose natural diet consists primarily of meat, not dairy. In the wild, feral cats get most of their moisture from the prey animals they hunt and eat, which are high in protein with moderate fat (1). Domestic cats share the same biological makeup and nutritional needs as their undomesticated relatives. Their ideal diet reflects what cats evolved to eat in nature before becoming pets.

The natural diet of feral and wild cats consists mainly of small animals like rodents, birds, amphibians and insects. Cats are hunters who have adapted metabolically over thousands of years to thrive on the nutrition available in their prey. Their bodies are designed to digest high amounts of protein, moderate fat and minimal carbohydrates from whole animal sources (2).

Since the natural cat diet is based on prey animals, it contains very little plant matter or dairy. Carbs and plants were not significant parts of feline diets throughout evolution. The domestic cat remains a natural carnivore optimized for eating meat, not omnivorous foods like grains, veggies or milk.

(1) https://www.petmd.com/blogs/nutritionnuggets/cat/dr-coates/2016/april/feed-cats-they-eat-wild-33956

(2) https://www.foodfurlife.com/the-natural-diet-of-the-cat.html

Why Do Cats Like Milk?

Kittens need milk from their mother to survive, so cats retain an instinctive attraction to milk. When kittens are born, they rely entirely on their mother’s milk for sustenance during the first several weeks of life. According to veterinarian Dr. Katy Nelson, this early dependence on milk creates an association in cats’ brains between milk and nourishment that can last into adulthood.

In addition, milk contains nutrients like fat, protein and calcium that cats need for growth and development. As obligate carnivores, cats require a high-protein diet with moderate fat content. Milk can provide concentrated sources of these nutrients. So when presented with milk, many cats are compelled by generations of instinct to drink it for its perceived nutritional value.

However, as cats mature, most lose the ability to digest milk properly due to a lack of lactase enzymes. So while the initial attraction remains, milk does not offer the same nutritional benefits to adult cats as it does to nursing kittens. According to veterinarian Dr. Lorie Huston, the cat’s lifelong association between milk and food drives their desire to drink it, even after milk stops being digestible.




Is Milk Good for Cats?

The short answer is no. Most cats are lactose intolerant and can’t properly digest milk. Milk and dairy products contain a sugar called lactose that requires an enzyme called lactase to digest. Kittens are born with this enzyme, but it begins to decrease after weaning and into adulthood. When cats drink milk, it can upset their digestive system and cause diarrhea (1).

While some cats may enjoy the taste of milk, it does not provide any nutritional benefits. Cow’s milk is nutritionally balanced for calves, not cats. Milk can also cause painful stomach cramps, gas, and bloating. The high-fat content of whole milk can trigger inflammation of the pancreas (pancreatitis) (2).

The nutritional composition and lactose content of cow’s milk makes it very difficult for adult cats to properly digest and tolerate. Therefore, it’s generally recommended to avoid giving your cat cow’s milk. The risks outweigh any temporary enjoyment they may get from the taste.


(1) https://www.petmd.com/cat/nutrition/can-cats-drink-milk

(2) https://hastingsvet.com/are-cats-allowed-to-drink-milk-the-answer-is-no-heres-why/

Safer Milk Alternatives

Although cow’s milk contains lactose that can be difficult for cats to digest, there are some safer milk alternatives for cats that contain less lactose:

Lactose-free milk: Milk that has the lactose enzyme added to help break down lactose can be easier for some cats to digest (source). Brands like Lactaid make lactose-free cow’s milk.

Goat’s milk: Goat’s milk contains less lactose than regular cow’s milk, so it may be better tolerated by some cats (source).

Kitten milk replacer: Products like KMR are formulated to meet the nutritional needs of kittens and contain milk proteins and fat without the lactose.

While these alternatives may be easier for a cat to digest than regular cow’s milk, they can still potentially cause digestive upset. It’s best to introduce them slowly and discontinue use if any diarrhea or vomiting occurs.

Providing Water for Cats

Cats should primarily drink water, not milk, to stay hydrated and healthy. Water supports kidney function, digestion, and overall wellbeing. In their natural habitat, cats get most of their moisture from eating prey. But domestic cats rely on us to provide clean, fresh drinking water. Make water enticing and readily available to encourage your cat to drink up.

Place water bowls around your home so there’s always one in reach. Consider getting a pet fountain, which provides constantly flowing water some cats prefer. Try adding a couple drops of tuna juice or chicken broth to the water for more appeal. You can also add freeze-dried chicken or tuna treats to the water, which will float and pique your cat’s interest. Feed wet food, which has high water content. Ice cubes or frozen broth cubes in the water add interest too. The key is making water more tempting than milk.

Ideally, cats should drink about 1 oz of water per pound of body weight per day. So a 10 lb cat needs around 10 oz, or about 1.25 cups of water daily. More if it’s hot out or your cat is ill. Monitor intake and make adjustments if your cat isn’t drinking enough. Providing fresh, flavored water in multiple spots encourages proper hydration.

Milk as an Occasional Treat

Small amounts of milk can be ok for cats to have as an occasional treat. Since milk is not part of a cat’s natural diet, it should only be provided in moderation.

According to experts, limit milk to about a tablespoon or two at a time if given as a treat. More than that may be problematic for a cat’s digestive system.

As with any treat, milk should only be provided sparingly. Treats should make up no more than 10% of a cat’s daily caloric intake. So 1-2 tablespoons of milk a couple times a week can be an acceptable amount for many cats.

It’s best to monitor your cat after providing milk to watch for any signs of intolerance like diarrhea or vomiting. If your cat seems to tolerate small amounts well, occasional milk can be a special snack.

Signs of Milk Intolerance

Diarrhea, vomiting, gas, and upset stomach after drinking milk are signs your cat may be lactose intolerant. According to VCA Animal Hospitals, the signs of milk intolerance include “diarrhea, vomiting, bloating, and abdominal discomfort after ingesting cow’s or goat’s milk.” Lactose intolerant cats often exhibit symptoms within 8-12 hours of consuming dairy, such as diarrhea and vomiting, as noted by CTVSH.

When to Avoid Milk

For kittens, milk should be avoided after the weaning process, which typically occurs between 4-10 weeks of age (1). At this point, kittens are developmentally ready for solid food and no longer require their mother’s milk for nutrition.

For adult cats, milk is generally unnecessary and can lead to digestive upset. Cats are lactose intolerant, meaning they lack the enzyme needed to properly digest lactose in milk (2). Consuming milk can result in diarrhea, gas, vomiting, and other signs of intestinal distress in adult cats.

Senior cats should also avoid milk, as digestive issues become more common with age. The incidence of lactose intolerance increases as cats get older, making seniors more prone to milk intolerance than younger adult cats (3). It’s best to avoid milk to prevent gastrointestinal complications.

Healthier Treat Alternatives

While milk may seem like an appealing treat for cats, there are many healthier alternatives that provide nutrition without the potential for stomach upset. Here are some recommended options:

Low sodium chicken or beef broth can make an enticing treat when frozen into ice cubes. The broth provides a tasty flavor cats love, and the low sodium content is easier on their stomachs. Just pour broth into an ice tray or small containers and freeze.

Bonito flakes are a common treat made from dried, fermented, and smoked skipjack tuna. These thin, crispy flakes are naturally savory and packed with umami flavor. Sprinkling a few flakes over food or offering them on their own makes for an irresistible treat. Just check the label to ensure no seasonings or additives are included.

Churu puree tube treats offer a smooth, protein-rich paste cats adore. The purees come in flavors like tuna, chicken, and crab, providing a strong taste cats crave. Churus are conveniently packaged in squeezable tubes, allowing easy portion control. Just squeeze out a small bit onto a fingertip or plate as an occasional treat.

Freeze dried meat treats retain more nutrients since they are simply dehydrated rather than cooked. Options like freeze dried salmon, turkey, or chicken make great training rewards or snacks. Just break into small pieces and limit to a few per day. The pure meat content is healthy and enticing for cats.

The Bottom Line

Despite the popular cultural association between cats and milk, cats do not actually need milk as part of their diet. Cats are obligate carnivores, meaning they require meat-based proteins as the foundation of their nutritional needs.

While kittens do drink their mother’s milk when young, their bodies stop producing the enzyme lactase after weaning, making it difficult for adult cats to properly digest the lactose in cow’s milk. Drinking milk can lead to digestive upset like diarrhea or vomiting in many cats.

Small amounts of milk or milk-based products can be offered as an occasional treat, but they should not make up a significant part of your cat’s diet. When choosing milk for cats, look for products designed for feline digestion, like lactose-free milk or cat milk replacements made from bone broth or goat’s milk.

The healthiest diet for cats focuses on quality proteins from meat, fish, or egg ingredients paired with a balance of vitamins and minerals. Feed your cat a complete and balanced commercial cat food diet and always provide fresh, clean water. Focus treats on healthy meat-based options rather than milk products.

While milk holds cultural significance for cats, science shows cats do not actually need milk after weaning. Support your cat’s obligate carnivore needs with plenty of proteins and limit milk to occasional small treats if tolerated.

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