Weight gain is an unfortunate side-effect of successful insulin treatment, because the body, now able to process glucose, is once more able to send the excess glucose not used for energy into storage as fat .
Obesity , whether caused by diabetes or pre-existing, can of course, have its own problems 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. An 2005 ACVIM abstract(#93) by Drs. Fleeman, Rand, et al., shows that in obese dogs, insulin sensitivity is cut in half .
With dogs, the results of informal polls taken at CDMB show that most were overweight at diagnosis.
Obviously the best route is to prevent overweight in the first place, by counting calories, and making sure the animal gets plenty of exercise.
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.
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 .
Weight loss can mean your dog needs less insulin to stay in control.
A diet containing more fiber can be helpful for dogs who are both overweight and diabetic . 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 .
Exercise and active playEditDr. Harkin of Kansas State University is a believer in exercise for all his patients--canine and feline .
Note: Exercise will often noticeably affect a dog's insulin requirements and blood sugar levels. 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 .
Unexpected or infrequent exercise can mean a "surprise" hypoglycemia episode. Any event that means more than the usual (and planned for) activity, can cause a low, since the food that supplies energy is used faster than expected.  Some extra food before or directly after the exercise or excitement can make this easily managed. Excitement generally means more activity than normal, so it needs to fall into the category of "exercise" and possibly "fed" to avoid low blood glucose problems. 
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 .
- ↑ Insulin and Weight Gain. Mayo clinic.
- ↑ German AJ, Hervera M, Hunter L, Holden SL, Morris PJ, Biourge V, Trayhurn P. (2009). Improvement in insulin resistance and reduction in plasma inflammatory adipokines after weight loss in obese dogs. Domestic Animal Endocrinology.
- ↑ German, Alexander J. (2006). The Growing Problem of Obesity in Dogs and Cats-pages 3-4. University of Liverpool WALTHAM International Sciences Symposia.
- ↑ Verkest, Kurt, Fleeman, Linda, Rand, Jacqueline, Morton, John M. (2005). Insulin Sensitivity and Overweight-Abstract #93-page-35. ACVIM.
- ↑ Canine Diabetes-Dietary Management. WebMD.
- ↑ Schermerhorn, Thomas (2001). Persistent Hyperglycemia in Dogs and Cats-Standards of Care-page 10. Standards of Care-Compendium.
- ↑ Diabetes in Dogs. PetsHealth.com.
- ↑ Obesity FAQs. Pet Education.com.
- ↑ Diet & Exercise in Dogs. BD Diabetes.
- ↑ Bruyette, David (2001). Diabetes Mellitus Treatment Options. WSAVA.
- ↑ Harkin, Kenneth. K State News Release. Kansas State University.
- ↑ Exercise-Managing Exercise. Intervet.
- ↑ Diet & Exercise for Diabetic Dogs. BD Diabetes.
- ↑ Mixing Medications and Exercise. Readers' Digest.
- ↑ Perkins, Bruce A., Riddell, Michael C.. Diabetes and Exercise page 2. Diabetes.ca.
- ↑ Cook, Audrey (1 April 2010). Identifying the reasons behind difficult-to-control diabetes in dogs. DVM 360.
- ↑ Variables affecting chemistry results. Cornell University.
- ↑ Greco, Deborah (2010). Treating Diabetes Mellitus in Dogs and Cats. Western Veterinary Conference.
- ↑ Schaer, Michael (2008). Diabetic Phenomena. WSAVA.
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