Go figure.

Funny thing is, I didn't find these articles until after I started the blog:

An overeating, slothful horse leads to an obese horse. Unlike humans, however, horse owners often don't see the dangers of an obese horse. Caretakers may see no harm in giving their horses rich foods, but obesity in horses is just as unhealthy as obesity in humans and can lead to fatal diseases.

University of Missouri-Columbia. "Horses Suffer From Obesity, Just Like Humans." ScienceDaily 25 April 2007. [read article]

And another:

Horses face serious health risks because of obesity, according to recent research. Fifty-one percent of the horses evaluated during the pioneering research were determined to be overweight or obese -- and may be subject to serious health problems like laminitis and hyperinsulinemia. And just like people, it appears as though the culprits are over-eating and lack of exercise.

Virginia Tech. "Fat Horses Face Health Problems." ScienceDaily 10 July 2007. [read article]

So, maybe I'm on to something here.