Obesity rates among people worldwide have soared over the last several decades -- but it turns out that humans aren't the only ones packing on the pounds. According to a recent study from the University of Alabama, many animals that spend time living around humans are evidently more prone to becoming overweight, and researchers aren't entirely sure why.David Allison, who studies obesity at the UA Birmingham, discovered an inexplicable trend of weight gain in small primates kept in the the university's laboratory. In hopes of learning more about the phenomenon, Allison compared his findings with 24 other data samples collected for animals ranging from domesticated dogs and cats to feral rats and chimpanzees used for research -- and what it pointed to was quite troubling. Animals are getting fatter, just like we are.
There was no single thread running through all 24 data sets that would explain a gain in weight. The animals in some of the data sets might have had access to richer food, but that was not the case in all data sets. Some of the animals might have become less active, but others would have remained at normal activity levels. Yet, they all showed overall weight gain.
The skyrocketing rates of obesity among humans over the last several decades has been attributed to unhealthy diets and increasingly sedentary lifestyles -- but, to Allison's surprise, those factors don't appear to be responsible for the animals in the study getting pudgier. In fact, at least for the lab's primates, they should be getting thinner.
"We can't explain the changes in [the animals] body weight by the fact that they eat out at restaurants more often or the fact that they get less physical education in schools," the researcher quipped in an interview with LiveScience. "There can be other factors beyond what we obviously reach for."
In the absence of any obvious reason why animals are getting fatter, some researchers are beginning to suspect the culprit may be a bit more surreptitious. Chemical additives and genetically modified food sources have been linked to childhood obesity -- and a similar process seems to be taking place within animals.
Unfortunately, this disturbing trend could mean that the overall health of the animals around us is in decline, which might have broader-reaching implications not yet fully understood. But there is one bright spot -- while it may become harder to get your chubby pooch to play fetch, teaching him to roll over and stay will probably be a bit easier.