In theory, weight management—for both people and horses—is simple, said Tania Cubitt, PhD: Eat less, exercise more, and lose weight.

Nonetheless, obesity remains a problem for not only horses but the people who care for them as well. Approximately 70% of American adults are either overweight or obese, she reported, noting that recent studies in horses have found obesity in 32% to 62% of animals. So if the weight management concept is that simple, she asked, why isn’t it working?

Cubitt, an equine nutritionist for Performance Horse Nutrition in Weiser, Idaho, presented a lecture on ways to manage equine obesity at the 2013 Alltech Symposium, held May 19-22 in Lexington, Ky.

Obesity has a number of causes, Cubitt said, ranging from genetics to improved forage quality (horses didn’t evolve eating bright green grass, she noted; rather, they consumed sparse, high fiber forage) to a lack of exercise. And it’s at the root of a number of serious health problems, including insulin resistance, chronic inflammation, oxidative stress, and possibly even a decreased life span