The following are the transcribed notes of Rebecca Price MD.  The notes are based on lectures given by Deborah Greco DVM at the MVMA Seminar in Telluride, Colorado, March 2005.  Any errors contained within are solely the responsibility of Dr. Price.


Dietary Recommendations for Cats with DM

Deborah Greco, DVM, PhD, ACVIM

March 2005



Dietary Recommendations

·          High protein and fat, low carbohydrate (CHO)

·          Most CANNED cat foods generally meet the requirements

·          Avoid cat foods containing rice and corn starch as they have a high glycemic index

·          Dr. Greco recommends canned Purina DM or if the cat won’t eat this, Fancy Feast


Carbohydrate (dry matter) content of dry/canned foods


                Product                  CHO                        Protein                   Fat

                                                Dry/canned            Dry/canned            Dry/canned           

M/D                          18/12                       55/55                       15/22

Iams Kitten               23/7                         34/38                       22/54

Growth                    29/7                         38/49                       27/36

W/D                         39/24                       38/41                       22/28

Purina DM                15/5                         57/55                       22/28



Reduction of Obesity

·          Cats are fed 300 kcal/kg/day for ideal body weight (feed about 1/3 less to reduce weight)

·          Most cats receive 300 kcal/day in 2 divided feedings

·          Often cats will not finish portions – perhaps due to satiety?


Study #1: published in Journal of Feline Medicine and Surgery, 2003:


1) DEXA* study: Materials and Methods

·          18 client owned diabetic cats (type 2)

o         All but 4 cats were on insulin already

o         All cats ate dry food exclusively prior to study

·          Cats received acarbose (12.5 mg po BID) and a diet containing 49% protein, 7% carbohydrate, and 42% fat

·          Fed 300 kcal/cat/day in 2 meals

·          Duration of study: 16 weeks

·          DEXA, fructosamine, and glucose measured pre and post-study


*DEXA is a radiological method that can be used to accurately determine body composition


2) DEXA/Fructosamine results: Responders (went off insulin)




% body fat



Grams fat



Grams lean



Fructosamine (micromoles/Liter)


284 *

Serum Glucose (mg/dl)





*Significant difference











Weight stayed the same in many of the cats, but the body mass composition dramatically changed.  Note that these were obese to start with, i.e. their % body fat was too high.  Average % body fat decreased from 42 to 36 over the four months of the study.

3) DEXA/Fructosamine results: non-responders (insulin doses were reduced but insulin was still required at the end of the study)





% body fat



Grams fat



Grams lean



Fructosamine (micromoles/Liter)


529 *

Serum Glucose (mg/dl)





*Significant difference

Again, note the dramatic change in body composition, although this time, the % body fat increased.  The percent body fat post-study was still below the ideal of 30%.


4)  What happened to body composition?


Normal Body Fat



Underweight   ►│◄  Overweight



Body composition tended to approach the ideal on a low carb, high protein diet, regardless of if the cat was underweight or overweight to start with.



Study #2: Low Carbohydrate versus High Fiber Diet in Diabetic Cats


·          Bennet N., Greco DS, Peterson ME

·          Compare the effect of a high fiber vs low carbohydrate diet on glycemic control in diabetic cats

·          Supported by a grant from the Morris Animal Foundation



1) Subjects:


·          81 diabetic cats initially, 18 excluded due to disease or diet refusal

·          Number in study=63, 14 female, 48 male, average body weight 6 kg (13.2 pounds)

·          Median age=11 years

·          Average Body Condition Score (BCS) 7/9

·          Length of time with diabetes mellitus:

o         >12 months

o         25 >2.5 months < 12 months

o         19 <2.5 months


2) Materials and Methods:


·          Insulin:  Blue Ridge PZI (n=53), NPH (n=2), Lente (n=6), Ultralente (n=1)

o         Average pre-study dose: 0.6 U/kg (.27 U/pound) BID

·          Diets:

o         Hill’s® Science Diet® Feline Growth® (Low Carbohydrate) – 31 cats

o         Hill’s® Prescription Diet® W/D® (High Fiber) – 32 cats

·          Monitoring

o         CBC/Chemistry/Fructosamine/Urinalysis(UA)/T4/Free T4 (thyroid function)

o         Four monthly exams for all study cats

·          7 of the non-responders in the High Fiber group were crossed over to Low Carbohydrate diet



3) Results:  Regulation (defined as fructosamine <400 & resolution of clinical signs)


·          Prior to the study, only 10% were well-regulated at entry (6/63)

·          81% of all cats fed Low Carbohydrate (LC) were better regulated post-study

·          56% of all cats fed High Fiber (HF) were better regulated post-study

·          At the end of the study, 32% of LC cats and 59% of HF cats still required insulin (mean dose 0.5 U/kg)

·          At the end of the study, 40% of the LC cats and 26% of HF cats were better regulated on fructosamine <400

·          Based on clinical signs, 100% of the LC cats and 89% of HF were better regulated


4) Number of cats off insulin:


·          LOW CARBOHYDRATE DIET (6-7% carbohydrate)

o         68% of cats went off insulin

o         60% of cats remained off insulin >1 year

·          HIGH FIBER DIET (12-15% carbohydrate)

o         40% of cats went off insulin

o         35% remained off insulin for >1year

·          Cats on LC were 3-4 times more likely to discontinue insulin

·          All cats were fed CANNED food only


5)  What happened to body composition?


Normal Body Fat



Underweight   ►│◄  Overweight


Because this was CANNED food, the percentage carbohydrate in both diets was much lower than the percentage carbohydrates in a dry food diet.  The lower carbs appeared to cause weight to normalize in both underweight and overweight cats.