Weight gain is an unfortunate side-effect of successful insulin treatment, probably because without being able to control its own food absorption, the animal's usual weight control mechanism no longer works well. In addition, hyperglycemia can make an animal feel sluggish, and neuropathy can make walking and running difficult, so the animal may get less exercise than before.

"What, me fat?" Jock is getting insulin and regulated, but tends to eat too much now. Click to zoom.

Obesity , whether caused by diabetes or pre-existing, can of course have its own problems[1] and complications, such as heart disease and insulin resistance. In fact, overweight can lead to diabetes in dogs or cats just as it does in humans, through insulin resistance[2]

In catsEdit

Being overweight is a hazard particularly in cats, due to the possibility of fatty liver (hepatic lipadosis[3]) that comes from fasting, or too-drastic weight-loss diets. A cat with inadequate food will start trying to consume stored body fat.

An overweight cat should never be allowed to stop eating, or diet too drastically, (less than 60-70% of required calorie intake is too drastic)[4] because the liver can be quickly overwhelmed with processing all that fat, leading to fatty liver, which can be fatal[5].


A healthy pancreas produces amylin as well as insulin, and the combination helps regulate stomach contents release and carbohydrate usage in the body. Recently, type-II diabetic humans treated with insulin+amylin have been shown[6] to gain less weight and control blood sugar better than those treated with insulin alone. This is apparently not the case with Type-I diabetics, so this treatment may be more appropriate in cats than in dogs, someday.

In dogsEdit

With dogs, the results of informal polls taken at CDMB show that most were overweight at diagnosis. As with dogs, the typical cat with diabetes is generally overweight at diagnosis[7], though if diagnosis comes later, they may instead be drastically underweight.


Obviously the best route is to prevent overweight in the first place, by counting calories, and making sure the animal gets plenty of exercise. An active cat's energy requirements are normally 45-65kcal/kg. Complete details on calorie counting and nutrient composition at the link below[8].

Unregulated diabetics without proper insulin dosage will need considerably more food! It is usually counterproductive to try reducing calories for an unregulated diabetic, since their food is not being absorbed into the body and they will always be hungry.

Slimming down--graduallyEdit

Reduction of weight to normal levels also reduces any insulin resistance the added weight caused. Weight reduction for both pets and people should be done gradually, over an approximate 2-4 month period[9][10].

In cats, losing the excess weight may mean the ability to stop insulin injections[11].

Even if weight loss doesn't mean the end of insulin shots for your pet, it can mean that he or she needs less insulin to stay in control.

A diet containing more fiber can be helpful for dogs (and perhaps cats) who are both overweight and diabetic[12] . Fiber helps with weight loss and can prevent food spikes; the increase in fiber can lead to a decrease in the pet's insulin needs.

For cats, Dr. Rand suggests that the calories in a low-carbohydrate/high protein diet be reduced instead of switching to weight loss diets which contain high carbohydrates[13].

Exercise and active playEdit

Dr. Harkin of Kansas State University is a believer in exercise for all his patients--canine and feline. Active play can be a fun way to "work out"[14].

Note: Exercise will often noticeably affect a cat or dog's insulin requirements and blood sugar levels. Informal polls on the FDMB show that the effect differs considerably from animal to animal, and may either raise or lower blood glucose levels depending on the individual. This is something you should find out about your pet and keep in mind when increasing exercise. Exercise should be avoided at or near the peak time of the pet's insulin, as the action can result in hypoglycemia[15][16][17].

In order to avoid exercise induced lows, it needs to become a part of the daily routine. Regularly exercised muscles aren't as dependent on the insulin "key" to receive glucose from the body for their fuel[18].

Further ReadingEdit





  1. FDMB thread regarding obesity and its problems
  2. . A 2005 ACVIM abstract (#93) by Drs. Fleeman, Rand, et al., shows that in obese dogs, insulin sensitivity is cut in half.
  3. hepatic lipidosis
  4. Weight Reduction in Cats, from VIN
  5. Weight Reduction-Cats-Drs. Foster & Smith Pet Education Library
  6. Symlin -- synthetic amylin to help control weight in Type-II diabetics
  7. Cats overweight at diagnosis
  8. Maxshouse-Feline Nutrition-Energy Requirements
  9. on diabetes in dogs
  10. Pet Education.dom-Drs. Foster & Smith-Obesity FAQ's
  11. News release on diabetes in cats
  12. High Fiber diet in diabetics
  13. Therapeutic Goals for Otherwise Healthy Diabetic Cats-WSAVA 2004-Drs. Rand & Martin
  14. BD Diabetes-Diet & Exercise for Diabetic Cats
  15. BD Diabetes-Diet & Exercise for Diabetic Dogs
  16. Readers Digest-Mixing Medications and Exercise
  17. Diabetes and Exercise page 2
  18. Diabetic Phenomema-WSAVA 2008
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