This article originally appeared on Dr. Mahaney’s The Daily Vet column on petMD. Obesity is a huge problem in both pets and people (pun intended). According to the Association for Pet Obesity Prevention (APOP), greater than 50 percent of pets in the United States are overweight or obese. That’s a remarkable percentage, which works out to approximately 89 million cats and dogs. Obesity leads to a variety of potentially irreversible health problems, including musculoskeletal system abnormalities, endocrine imbalance, cardiovascular disease, dermatologic abnormalities, cancer, and more. Obesity is the number one nutritional disease in pets. Yet when I ask pet owners and pet enthusiasts what they think is the number one nutritional disease of dogs and cats, obesity is typically not their answer. Usually, it’s malnutrition, or vitamin or mineral imbalance. Since commercially available pet food is the diet of choice for most American households, processed foods are extremely influential in creating the obesity epidemic in dogs and cats. Most pet owners live in fear of their potential to create nutritional imbalances in their pet by feeding a whole food-based diet made of real meat, vegetables, fruits, grains like we humans eat. Therefore, highly processed foods containing ingredients vastly different from those appearing in nature are chosen for most canine and feline companions. Pet owners are actually creating nutritional imbalances in their pets by feeding excessive amounts of nutritionally complete and balanced foods and treats. No matter how nutritionally complete and balanced the food is, consumption of a calorie surplus ultimately creates an unhealthy state. So, let’s delve further into the pet health problems to which being overweight or obese contributes. Musculoskeletal System Abnormalities Carrying extra weight stresses the musculoskeletal system (joints, ligaments, muscles tendons, etc.), which damages normal tissues and creates inflammation. Arthritis is joint inflammation which, when left unresolved, can lead to degenerative joint disease (DJD), permanent alterations in the cartilage surfaces. Additionally, overweight pets are more prone to torn ligaments (including cranial cruciate ligament rupture) and intervertebral disc disease (IVDD), where the disks that cushion the backbone malfunction and can even pinch on the spine or nerves. Endocrine Imbalance The endocrine system is a complicated network of glands and hormones that regulate the body’s ability to manage normal functions (digestion, immune system response, metabolism, water balance, etc.). Two of the most common endocrine diseases diagnosed in companion animals that are associated with obesity are diabetes and hypothyroidism. Diabetes occurs when the pancreas is unable to produce insulin or release it in sufficient quantities to appropriately regulate blood sugar. Hypothyroidism is an under functioning thyroid gland, which causes metabolism to slow down and leads to a variety of undesirable secondary conditions (weight gain, skin problems, high blood cholesterol, anemia, etc.). With both diabetes in cats and hypothyroidism in dogs, obesity increases the likelihood that these conditions will occur. Cardiovascular Disease The cardiovascular system is comprised of the heart and blood vessels (arteries and veins).Having to supply and drain blood from tissue beyond what the body is structurally prepared for causes the cardiovascular system’s components to work harder at circulating oxygen, nutrients, and white blood cells, while also removing toxins. Ultimately, high blood pressure, lack of circulation to body parts far away from the heart, and heart failure can result from of being overweight or obese. Dermatologic Abnormalities Excess flesh can create skin folds. Moisture accumulates between skin folds, which leads to inflammation (dermatitis) and fosters a climate appropriate for the growth of microorganisms (yeast, bacteria, etc.). Additionally, overweight or obese pets face more of a challenge grooming themselves to maintain a cleaner state of their skin or coat than animals at healthy weight. Cancer Being overweight or obese has a well documented correlation with caninebladder and mammary cancer. The inflammation generated by carrying too much weight promotes an internal environment that is friendly to the development of cancer. Additionally, diets rich in omega 6 fatty acids (such as animal-based fats) promote inflammation and have been linked to cancer cell growth. The good news is that obesity is completely preventable. To start, we pet owners should restrict the portions our canine and feline companions consume at each meal by 25-33 percent (one quarter to one third). Additionally, we need to consider the inherent nutrient value in feeding our pets a whole-food based diet instead of commercially available processed diets. Thirdly, we must shift our focus from giving food as a reward to instead providing praise, socialization, activity, and environmental enrichment. Skinny the Cat, Pet Obesity … Who is Responsible? from Pet Pause by Dr. B Dr. Patrick Mahaney Thank you for reading this article. Your questions and comments are completely welcome (I’ll respond). Please feel free to communicate with me through Twitter (@PatrickMahaney) and follow my adventures in veterinary medicine by liking Patrick Mahaney: Veterinarian Acupuncture Pain Management for Your Pets on Facebook. Copyright of this article (2012) is owned by Dr Patrick Mahaney, Veterinarian and Certified Veterinary Acupuncturist. Republishing any portion of this article must first be authorized by Dr Patrick Mahaney. Requests for republishing must be approved by Dr Patrick Mahaney and received in written format.