Effect of diets differing in fat content on chronic diarrhea in cats

Fat-restricted diets have been advocated for dogs with diarrhea for many years. Recommendations for cats with diarrhea have varied between low-fat and high-fat diets, but there have been no published studies to support either recommendation.

The objective of this study was to compare the clinical responses of cats with chronic diarrhea to dietary management using either a high fat or a low fat, highly digestible diet.

Sixty pet cats with chronic diarrhea were recruited; 55 cats completed the study.

Randomized, double-blinded, controlled clinical trial. Upon completion of baseline measures, cats were fed 1 of 2 diets for 6 weeks, during which the owners recorded fecal scores daily using an illustrated fecal score chart ranging from 0 (very watery) to 100 (firm and dry). After 6 weeks, cats were reevaluated by the attending veterinarians.

Fecal scores improved significantly, with 78.2% of cats improving by at least 25 points on the 100-point scale or having a final fecal score of at least 66. Over one third of the cats developed normal stools. There were no differences in clinical responses between the diets. Clinical improvement was noted within the 1st week, and maximized within 3 weeks.

These results show that dietary management can be helpful in cats with chronic diarrhea, but dietary fat content does not appear to affect the outcome. Cats that do not respond within 3 weeks should be evaluated further.