Interpreting a Sudden Dog Weight Gain

There are reasons for concern in the face of sudden dog weight gain. It's important to distinguish normal puppy weight gain from an abnormal amount of weight gain in a puppy. Weight management including a decrease in calories and an increase in activity is usually the only solution for dog weight gain. However, ruling out an underlying disease process can pose other options.

Ideal Weight

Slow puppy weight gain is normal but rapid dog weight gain can be a sign of an underlying problem at any age. You can determine whether the puppy weight gain is too rapid with the following formula. A toy or small breed dog should not weigh more than 10 pounds at 6 weeks. A medium to large dog should be about 40 pounds at 14 weeks and a very large breed of dog should be no more than 75 to 100 pounds at around 6 months of age. You should be able to feel the last 3 to 5 ribs of a dog with a light touch. Usually dog weight gain can be explained by too much food and not enough activity. Weight management techniques are usually necessary to control canine weight gain. Other treatments may be called for, however, if the sudden weight gain is due to an underlying disease.


Canine weight gain can often be explained by an under functioning thyroid gland. The excretion of the proper amount of thyroid helps regulate metabolism in dogs. A change in the functioning of the thyroid gland can lead to sudden dog weight gain or loss of weight in dogs. A diagnosis of hypothyroidism is most common in dogs over two or three years of age. The diagnosis should be made based on either a combination of free T4 and canine TSH analysis or solely free T4 testing using an equilibrium dialysis technique. Low T4 levels are sometimes referred to as "euthyroid sick syndrome" and can represent a systemic illness.

Other Diseases

A syndrome called Cushings Disease can also explain sudden puppy weight gain or dog weight gain. It is also called hyperadrenocorticism. Other signs of the disease include patches of hair loss, susceptibility to skin and bladder infections, a pendulous appearance to the abdomen, and increased drinking and urinating. If your dog suddenly appears to have a potbelly, he or she may have a serious medical problem. Cancer, heart or liver disease or bloat can cause a sudden enlargement in the abdomen. Your dog might also have a ruptured bladder which requires emergency veterinary care.

Arthritis or Injury

Arthritis or an injury to the knee can stop a dog in his tracks. The sudden drop in activity while eating the same amount of food can result in a somewhat rapid weight gain. Helping your dog lose weight through weight management techniques will help the arthritic symptoms. Some dogs also respond to glucosamine and chondroitin therapy, including through store bought supplements for dogs. Veterinary acupuncture, canine massage or canine chiropractic care can greatly help in recovery from arthritis or an injury to the knee.