There's More to Fat than Meets the Eye

Updated: November 15, 2013
Published: January 11, 2013
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Obviously, extra body fat adds to the weight of the body. Lugging around all that extra baggage generates wear and tear on joints, makes the cardiovascular and respiratory systems work harder than they should, and detracts from the joy of being a normal, active dog.

But there’s more to fat than meets the eye. We typically think of adipose tissue (the technical term for fat) as a way for the body to store energy. When dogs eat more calories than they burn off, the extra is stashed away to be used when resources are scarce. It’s a sensible system, but domesticated dogs rarely experience those "lean times" their fat was designed to help them weather.

Adipose tissue does more than store energy, however. It has been described as the largest endocrine (hormone producing) organ in the body. A partial list of hormones produced by fat cells includes leptin, several cytokines, adipsin and acylation-stimulating protein (ASP), angiotensinogen, plasminogen activator inhibitor-1 (PAI-1), adiponectin, steroid hormones, and resistin. 1 These hormones play a role in regulating inflammation, blood pressure, blood clotting, metabolic rates, the function of the immune system, reproduction, and healing.

When a dog is close to its ideal body weight, adipose tissue produces hormones at appropriate levels and in concert with all his other endocrine organs. Obesity throws the whole system out of whack. Is it any wonder then that obese dogs are at excessive risk for:

  • osteoarthritis
  • cruciate ligament rupture
  • intervertebral disk disease
  • congestive heart failure
  • respiratory disease
  • Cushing’s disease
  • skin disorders
  • infections
  • heat exhaustion and heat stroke
  • complications associated with anesthesia and surgery
  • many types of cancer

In fact, a 2005 study found that lean dogs lived almost two years longer than their overweight counterparts. Researchers paired up 48 Labrador retrievers. Essentially, one from each pair was allowed to eat as much as he or she wanted and the other was fed 75% of that amount from the time they were 8 weeks old until death. The study determined that the median life span of the restricted-fed dogs was 13 years but only 11.2 years in those individuals allowed free access to food.

Better health and a longer life … isn’t that worth keeping your dog slim?

Dr. Jennifer Coates


1. Adipose tissue hormones. Guerre-Millo M. J Endocrinol Invest. 2002 Nov;25(10):855-61. Review.

2. Influence of lifetime food restriction on causes, time, and predictors of death in dogs. Lawler DF, Evans RH, Larson BT, Spitznagel EL, Ellersieck MR, Kealy RD. J Am Vet Med Assoc. 2005 Jan 15;226(2):225-31.


Image: Lesley Rigg / via Shutterstock