By Teresa Garden, DVM
Ketogenic diets were first introduced in 1921. Sometimes, dietary fads and practices in human medicine may find their way into veterinary medicine. This is true for ketogenic diets. What exactly is a ketogenic diet? A ketogenic diet is one that is high in fat, low in carbohydrates, moderate in protein, and restricted in calories. With a normal diet, glucose broken down from carbohydrates is the primary form of dietary energy. But by limiting carbohydrates (and thus glucose) a ketogenic diet mimics a form of starvation. In that state, the body is forced to burn fat for energy. Fat is then converted to ketones which are used for energy in place of carbohydrates and glucose. This is referred to as ketosis.
Ketosis is a physiological state that produces elevated levels of ketones. Ketosis is readily produced in humans but dogs can be resistant to it. Dogs metabolize ketones much more rapidly than people so the state of ketosis is more difficult to achieve and maintain. It is also theorized that dogs can naturally tolerate longer periods of time without eating which makes them physiologically more resistant to developing ketosis. It is a strong possibility a diet high in fat and low in carbohydrates may not create the same biochemical changes in dogs as it does in people. These physiological differences between humans and companion animals make extrapolations unreliable.
There are some research studies regarding the use of these diets in people. Ketogenic diets have been shown to be useful for weight loss in people because they are calorie-restricted. There is some evidence that shows they may suppress appetite more than other kinds of low-calorie diets. Ketogenic diets are potentially dangerous and direct medical supervision is required in humans, usually by hospitalization. Compliance in human patients is a problem since the diets are unpalatable.
Ketosis may be neuroprotective. Evidence suggests ketone bodies have direct anticonvulsant activity in people. Ketogenic diets have been used in epileptic people who do not respond well to seizure medications. While it is unclear why they work, about two thirds of patients on a ketogenic diet showed significant improvement. Ketogenic diets were shown to be beneficial to epileptic children as well. The number of studies has been very limited with small sample sizes. Therefore, the overall quality of the evidence is considered low at present time. There is preliminary evidence ketogenic diets may slow progression of some types of cancer in people. The conclusion of a data review is that more consistent clinical evidence is needed before a ketogenic diet can be advised for any single cancer diagnosis or as adjunct therapy.
The evidence base for ketogenic diets is far more limited in veterinary patients. There are no clinical studies evaluating therapeutic ketogenic diets in cats. There are no published clinical trials evaluating ketogenic diets as a treatment for cancer in dogs. There are a couple of studies published regarding their use in neurological disease in dogs. In 2005 a study was performed on epileptic dogs that were not responding well to conventional medical therapy. One group was fed a normal diet. One group was fed a ketogenic diet.
They were studied for six months. It was concluded there was no statistical difference in seizure frequency between the two groups. There was a study that showed improvement in cognitive function in old beagles kept in a laboratory setting fed a ketogenic diet. But there are no studies evaluating the diet in naturally occurring cognitive dysfunction in pet dogs.
Besides not having a clinical benefit, feeding a ketogenic diet to your dog can cause adverse effects. Pancreatitis is a serious condition occurring in dogs fed an excess of dietary fat. Gastrointestinal symptoms, nutritional deficiencies, cardiac disease, and renal calculi have been reported as risks in people on therapeutic ketogenic diets. The safety of these diets in dogs and cats is unclear due to lack of relevant research. There is no compelling research evidence in dogs or cats showing a clinical benefit to ketogenic diets. As a veterinarian, I cannot recommend therapeutic ketogenic diets for dogs or cats at this time due to a lack of sufficient scientific evidence proving their efficacy and safety.
Dr. Teresa Garden is chief veterinarian /owner of Animal Health & Healing, a full-service holistic and conventional veterinary practice in the Maplewood/Richmond Heights area. 314-781-1738.