A study to evaluate the effect of diet on regulation of feline diabetics enrolled 62 cats with uncomplicated diabetes mellitus. Sixteen cats had been diagnosed >1yr prior to entering study, 12 had been diagnosed 4 mo-1 yr prior, and 34 had been diagnosed within 4 mo of beginning the study. Cats were excluded from study if they were on steroids, had other underlying disease, or would not eat the prescribed diet.

Cats were switched over to either a high fiber, low fat, non-carbohydrate (CHO) restricted diet or a low fiber, low CHO, high fat diet.

• Canned high fiber-type diet (equivalent to Hill's Feline w/d)
• Canned low CHO, high fat-type diet (equivalent to Purina DM)
  Diets have similar protein content (~40% on a dry matter basis).

CHO content: Hill's Feline canned w/d has ~26% CHO, of which ~12% is fiber; Purina canned DM has ~5% CHO.
Diet change was made rapidly.

All cats received insulin initially, to help reverse glucose toxicity. Most were receiving PZI insulin; ~10% were receiving other insulin types.
Insulin dose was reduced to 2 units or less q 12 hr in cats receiving the CHO restricted diet to avoid hypoglycemia.

Serum fructosamine concentration. Cats were considered well regulated if serum fructosamine was < 400 µmol/L.
Mid-day glucose concentration. Cats were considered euglycemic if glucose was < 180 mg/dL.

• 80% of cats given the CHO restricted diet were well regulated.
• 60% of cats given the non-CHO restricted diet were regulated.

• 68% of cats given the CHO restricted diet lost dependence on exogenous insulin.
• 35% of cats given the non-CHO restricted diet lost dependence on exogenous insulin.

Approximately equal proportions of cats from each "time since diagnosis" group lost exogenous insulin dependence, however, the time for insulin requirement to decrease after the dietary change was variable.

• Cats >30% overweight are more likely to lose insulin dependence.
• Cats <15% overweight are less likely to lose insulin dependence.