I have heard it said that humans are the only animals that worry about their nutrient intake, this is not true. While intuitive eating might be accurate for wild animals who grew up for tens of thousands of years to hundreds of thousands of years and have thus adapted their diets to the food that was available, such as Pandas eating almost exclusively Bamboo, but human’s are much more complex than that.
And so are animals.
Animals are often only used to intuitive eating if it is in the wild, but once an animal goes Urban, or are relocated, nutritional issues often soon result. Due to the high abundance of calorie laden foods and nutritionally defunct foods in urban environments. This can not only cause issues with vitamins and minerals, but can cause something even more severe: Obesity.
Free-Living baboons for instance, who are wild by live near civilization and have tons of food sources, were more likely to be less active, and have a body fat percentage 21% more than their forest dwelling counterparts. Also, in another study, captive Rhesus Monkeys and Macaques were found to be more prone to Obesity than their wild-dwelling counterparts. And if that is not enough, a single case study done on a pet Raccoon in 2008 showed it to have Type 2 Diabetes, which is caused by genetics and poor dietary choices.
Captivity and relocation may cause an animal severe harm through malnutrition as well, as mentioned by Tufts University:
Changes in diet through captivity or relocation may result in severe health problems. For example, some animals like the giraffe have a natural physiological requirement for browsing, while others require particular grasses. It has also been shown that dried hays and grasses commonly fed to our domestic livestock may not contain sufficient Vitamin E for some wild ungulates. Vitamin E related health problems will occur in these animals if supplementation or fresh grasses are not given.
Due to relocation of raccoons, for instance, up to 75% of raccoons die within the first year due to inability to find food, poor nutrition, stress, and many other factors.
So yes, animals that are born and raised in a single unchanging environment are able to focus on intuitive eating to get the proper nutrition, but animals in captivity, as puts, or situated around urban environments can’t focus that way. Probably due to “human” food tasting good overpowering the desire to seek out fresh fruits and veggies, and simply relying on scraps, which is also easier to do.
So no, humans are not the only animals who have to diet to get all of our nutritional needs.