Humans may not be the only species undergoing an obesity epidemic. In a study recently published by Proceedings B, a research journal of the Royal Society of Biological Sciences, scientists founds that rates of obesity have risen over time amongst eight species of animals that live with or around humans.

Weight Gain Across Species

Many factors contribute to the human obesity problem, although a decline in physical activity and unhealthy foods bare most of the blame. Yann C. Klimentidis and the other authors of the article say that observing the overall weight increase in animal species may shed insight onto other probable causes for weight gain.

The study observed 20,000 animals of eight different mammalian species including domestic dogs and cats, marmosets, lab mice, chimpanzees, and feral rats from urban environments.

In addition to finding a consistent rise in overweight individuals in a population, the study found that obesity increased across generations of animals that had never lived with or among humans and even laboratory animals that had highly controlled diets. This suggests that other factors beyond diet may be contributing to obesity rates.

In addition to a change in exercise and food quality, the study suggests that the following factors may contribute to the obesity epidemic:

• Growing up in germ-free environments
• Selective breeding that favors bigger and heavier animals
• An increase in endocrine-disrupting chemicals in the environment

A Warning For The Future

Klimentidis, et al. state that studying these animals is important because they can serve as "canaries," warning us about environmental problems before the issues have extreme effects on the human population. In particular, they say:

Although dietary practices and physical activity levels are the most thoroughly studied risk factors for obesity, findings in humans and our findings in other animals add to the increasing evidence that other potential risk factors which may work through diet and physical activity or through other means (e.g. nutrient-partitioning, metabolic efficiency) should be incorporated into public health research and environmental medicine.

Dieting Is Not Enough

While studying overall change over time will lead to valuable information about the causes of obesity, many pet owners struggle to help their obese pet lose weight in the present.

Weight control pet foods are a relatively recent addition to the market, but recent studies completed at Tufts University warns that the marketing is misleading about their benefits. The amount of calories in one cup of dried food varies widely from brand to brand, so no matter how it's marketed, the wary pet owner should check the ingredients and nutrition content.

Behavior modification to include more exercise and less food-related anxious behavior can help to reduce a pet's weight.

In the end, if a pet owner is trying to help their pet lose weight, she should talk to her veterinarian to make sure the pet does not have any other health problems and to establish a diet and exercise plan.

Read More:

• Canaries in the coal mine: a cross-species analysis of the plurality of obesity epidemics (Proceedings of The Royal Society of Biological Sciences)
• Your Cat Is Getting Fat (GOOD)
• Counting Calories in Diet Pet Food (The New York Times)
• The Overweight Pet (The Pet Center .com)