One of the most common questions regarding veterinary nutrition that I get from clients these days is about cats and grains. An argument often made about feline nutrition is that because they are obligate carnivores, cats are ill-equipped to eat carbohydrates and that since commercial diets often include grains and other carbohydrate sources, these must be nutritionally inappropriate for cats. This argument is especially tricky because it is partially correct and partially a fallacy. It is true that cats are obligate carnivores, and diets that exclude all animal products are nearly impossible to make so that they will meet cats’ nutritional needs. On the other hand, there is a significant difference between nutrients in a diet and the ingredients in the diet. Proteins and carbohydrates derived from plant sources can be just as digestible and nutritious for cats as those derived from animal sources. The devil is in the details, and it is usually unwise and inaccurate to make sweeping generalizations about pet nutrition.
A panel of nutrition and feline medicine experts from the American College of Veterinary Medicine (ACVIM) recently drafted a consensus statement on the role of dietary carbohydrates in feline obesity and diabetes which examines some of the evidence concerning dietary carbohydrates and cats. This statement clarifies some questions but also leaves room for debate because it is based not on pure theory and argument but on research evidence, and there are areas in which the research evidence is inconclusive. This sort of ambiguity can be quite frustrating, but it is better to acknowledge the limits of our understanding and work towards expanding them than to simply take the lack of definitive information as an excuse to accept and promote whatever theoretical argument most appeals to us.
The statement was presented at the recent ACVIM annual meeting in the form of a series of questions about dietary carbohydrates in feline diets with brief answers and then an assessment of the strength of the evidence supporting these answers. The statement itself should be published soon, and will doubtless instigate vigorous debate, as it should. I will post a link to the statement and updates as they become available. But for now, here is a summary of the statement as presented at the recent conference.
1. Are dietary carbohydrates an essential or required nutrient for cats?
Answer- No. Based on a good quality and quantity of evidence, most cats do not require dietary carbohydrates. There are some simple sugars in feline milk, so it is possible that nursing kittens may require these but no clear deficiency has been demonstrated.
2. Can cats effectively utilize dietary carbohydrates for energy and nutrition?
Answer- Yes. Based on a good quality and quantity of evidence, cats can effectively digest, absorb, and utilize dietary carbohydrates.
3. Do dietary carbohydrates in the diet cause obesity?
Answer- No. The cause of obesity in almost all cats is excessive calorie intake irrespective of whether the calories come from protein, fat, or carbohydrate. In fact, low carbohydrate foods may be more likely to lead to obesity if they are higher in fat than regular diets.
4. Do dietary carbohydrates contribute to the development of diabetes?
Answer- The consensus was that they do not, however the research evidence is very limited and not always consistent. The consensus was that even if carbohydrates do play a role as a risk factor for diabetes, this is dwarfed by the much more important factor of obesity.
5. Are low-carbohydrate diets useful in the management of feline diabetes?
Answer-Maybe. The evidence is limited and conflicting, and the committee did not achieve a consensus.
The lead presenter summarized the central finding of the panel with three words:
“It’s the calories, Stupid!”