Most animals that have been tested do prefer cooked food over raw food. This holds across a surprisingly wide range of species, from chimpanzees to dogs to mice. Decades of behavioral research confirm that when given a choice, animals consistently gravitate toward food that has been heated, and the reasons go deeper than simple taste.
What the Experiments Actually Show
The most striking evidence comes from chimpanzees. In a series of experiments, researchers offered chimps both cooked and raw potatoes. The chimps didn’t just prefer the cooked version; they were willing to trade raw potatoes they already had in exchange for cooked ones. When given access to a “cooking pot” (a device that transformed raw food into cooked food), chimps learned to place their raw potatoes inside it and eat the cooked result immediately. They even transported raw food from a distance and saved it specifically to use in the pot later, delaying the instant gratification of eating raw food in favor of getting the cooked version.
Dogs show a similar pattern. Research on canine taste preferences found that dogs prefer cooked meat to raw meat, canned meat to fresh meat, and ground meat to cubed meat. The pattern points toward softer textures and richer flavors, both of which cooking produces.
Even mice, which have no exposure to cooking in the wild, respond to it. In a controlled study published in PNAS, mice maintained their body weight on cooked sweet potato diets but lost weight on raw sweet potato diets, even when eating comparable amounts. On meat diets, all mice lost weight (the portions were restricted), but those eating cooked beef lost significantly less than those eating raw beef. The mice weren’t exercising differently across diets either. They simply extracted more energy from the cooked food.
Why Cooked Food Delivers More Energy
Cooking does several things to food at a molecular level, and animals’ bodies respond to all of them. The most important is protein denaturation: heat unfolds the tightly coiled structure of proteins, making them far easier for digestive enzymes to break apart. Studies in pigs (whose digestive systems closely resemble ours) found that amino acids from moderately cooked meat appeared in the bloodstream within 15 minutes and peaked about 2.5 hours after eating. Overcooking reverses some of this benefit. Meat cooked at very high temperatures actually became harder to digest, with amino acid absorption slowing considerably.
The starch in tubers and grains undergoes a similar transformation. Raw starch granules are crystalline and resist digestion, but heat causes them to swell and gelatinize, making them accessible to digestive enzymes. This is why mice on cooked sweet potatoes maintained their weight while those on raw sweet potatoes, even when pounded into smaller pieces, kept losing it. Cooking did what mechanical processing alone could not.
Cooking Removes Things That Make Raw Food Harmful
Beyond making nutrients more available, cooking neutralizes compounds in plants that actively interfere with digestion or cause toxicity. Lectins are a prime example. These proteins, concentrated in raw legumes like kidney beans, bind to the gut lining and can cause severe food poisoning. Boiling eliminates them: 10 minutes of boiling destroys the toxic lectin in kidney beans, and cooking legumes at 95°C for an hour reduces overall lectin activity by 94 to nearly 100%.
Oxalates, which bind to calcium and can contribute to kidney stones, drop by 30 to 87% with boiling. Phytates, which lock up minerals like iron and zinc, decrease by 11 to 80% depending on the food. Goitrogens, compounds in cruciferous vegetables that can interfere with thyroid function, are reduced by cooking and fermentation. For any animal eating plants, cooked food is not just easier to digest but genuinely safer.
The Evolutionary Connection
The fact that animals with no cultural history of cooking still prefer cooked food suggests something important: the preference isn’t learned behavior. It’s a response to real sensory and nutritional signals. Cooked food smells different, tastes different, and has a softer texture. Animals appear to detect, through taste and perhaps through post-digestive feedback, that cooked food is a better deal.
This observation is central to the “cooking hypothesis” of human evolution, most associated with biological anthropologist Richard Wrangham. The argument is that early humans’ adoption of fire and cooking was not a cultural luxury but a biological turning point. Modern humans cannot survive on a diet of raw wild foods. Our jaws and teeth are too small, and our guts are too short compared to other primates. These anatomical changes trace back to early members of our genus, well before 400,000 years ago, when archaeological evidence of widespread fire use becomes common. The implication is that our ancestors began relying on cooked food early enough that our bodies evolved around it.
Chimpanzees offer a window into what that transition might have looked like. They already prefer cooked food, understand cause and effect well enough to use a cooking device, and will delay eating raw food to “cook” it first. They lack only the ability to control fire.
Are There Animals That Prefer Raw Food?
No species tested in controlled experiments has shown a clear preference for raw food over cooked food when both are offered side by side. That said, the research has focused on omnivores and carnivores, particularly primates, dogs, and rodents. Obligate herbivores like cows or horses, whose multi-chambered stomachs or enlarged ceca are specifically designed to ferment raw plant fiber, have not been tested in the same way, and cooking would likely destroy the fibrous structure their gut bacteria depend on.
Strict carnivores present a more nuanced picture. While cats are known to be selective eaters, the available research hasn’t produced the same clear cooked-over-raw preference data that exists for dogs. Cats are highly sensitive to texture and temperature, and their preferences can vary based on factors like moisture content and fat levels rather than whether food has been heated.
There’s also a practical limit to the benefits of cooking. Overcooking degrades food quality. In the pig digestion studies, meat heated above 100°C became harder to digest than meat cooked at moderate temperatures. So the preference for cooked food is really a preference for optimally processed food, not simply for food that has been exposed to the most heat possible.