Nutritional Assessment

A nutritional assessment should be performed for every cat at every visit. Key information to gather includes the type of food, the brand, the amount fed, the frequency of feeding, and the amount actually eaten, as well as type and amounts of any supplements or treats provided. This information is helpful in determining how appropriate the nutritional plan is for this cat’s life stage, health conditions, body, weight and muscle condition. Having reception staff prepare the client in advance by asking them to bring this information with them (e.g., taking photos of the products fed, the bowl size), can save time and provide a more accurate assessment. Similarly, designating a staff member to make a follow-up phone call after the visit to collect any missing details.

At every appointment, review and repeat the nutritional assessment and make a recommendation that includes a specific diet, the amount to be fed (by volume or weight), as well as frequency of feeding. Table 1 provides information on recommended daily caloric intake for cats. Record this information in the medical record and communicate it to the client both verbally as well as in written form.

Table 1

Maintenance DER (Kcal/day):

Normal, neutered adult = 1.2 x RER
Intact adult = 1.4 x RER
Obese prone adult = 1.0 x RER
For weight loss in overweight adults = 0.8 x RER
Growing kittens = 2.5 x RER
Thin Senior cats: 1.4 X RER

RER = Resting Energy Requirement: the energy required for a normal individual at rest in a thermoneutral environment based on body weight.

DER = Daily Energy Requirement: the average daily energy expenditure of an animal dependent on life stage and activity (work, lactation, gestation, growth).

Healthy Body Weight and Obesity Prevention

  • Preventive healthcare includes monitoring weight, body condition, and muscle condition. Controlling energy intake is important for the prevention of obesity and maintenance of ideal body weight. Individual cats may have energy requirements 50% or more above or below the average requirement. The true daily energy requirement for an individual cat is the calories needed to maintain an ideal body condition score (BCS 2.5-3.5 on the 5-point scale or 5 on the 9-point scale) and stable weight.
  • It is also helpful to note not just whether weight is stable, has increased, or has decreased, but also the percentage weight change as this helps to detect insidious changes, thereby potentially preventing future obesity or facilitating early detection of disease.
  • Percent weight change

Previous weight – today’s weight X 100 previous weight

Example: (4.5 kg-4.0 kg)/4.5 kg = 0.5/4.5 = 0.111 = 11%
(10 lb-8.8 lb)/10 lb = 1.16/10 = 0.111 = 11%

This mere 0.5 kg (1.2 lb) is equivalent to a weight loss of 14.4 lb or 6.5 kg in a 130 lb (59 kg) adult.

  • Body condition can be determined by several methods. Three common methods include using the 5-point or 9-point body condition score charts and body fat index. For cats determined to be above ideal weight, assessment of body fat using the body fat index chart or morphometric measurements can help to estimate the cat’s ideal body weight. With this information the food dose can be calculated for that individual. The ideal body weight for all cats, not just those that are overweight, should be recorded in the cat’s medical record for future reference.
  • Loss of muscle can occur (especially in older cats, sarcopenia) without fat loss or a decrease in BCS and individuals can retain an obese or overweight BCS yet be under muscled. A muscle-wasted  patient may be suffering from a catabolic disease (e.g., neoplasia, a protein-losing nephropathy or enteropathy), be unable to absorb dietary protein efficiently (e.g., intestinal disease), or may need a diet with more protein. Muscle condition scoring (MCS) is a subjective way to evaluate lean body mass (LBM). Therefore, both BCS and MCS should be performed in all cats, to evaluate fat mass and lean mass independently of each other. When clients participate in determining BCS and MCS, it becomes more meaningful to them.
  • In some chronic disease states (e.g., neoplasia, congestive heart failure, chronic kidney disease), optimal weight may be higher than “ideal weight”.

Food Choices, Nutritional Information, and Weight Gain

  • Today’s pet foods are more palatable than in the past and the caloric content of cat foods varies widely. Feeding unlimited amounts of highly palatable, energy dense foods encourages excessive caloric intake. A cat should like what it eats, but not necessarily love it.
  • Feeding multiple small meals each day is recommended as it may allow for better control of caloric intake as well as allowing the cat to express normal feeding behaviour.
  • Daily food allotments should be measured carefully; weighing dry diets on a kitchen scale is more accurate than measuring by volume.
  • Nutritional information should be available from the food manufacturer; producers of premium foods provide full nutritional information to veterinary staff. If the manufacturer’s recommended feeding amounts are used, excess caloric intake may result because recommendations are based on ranges and average caloric requirements.
  • Excessive use of treats or substitution of food (and treats) for other types of interaction between the client and cat encourages excess energy intake. Snacks should be limited to >10% of the total daily caloric intake.
  • Supplements should be used judiciously as micronutrient balance may be lost. In general, a complete and balanced diet (AAFCO certified) meets nutritional requirements.
  • Canned food offers several benefits, including increased water intake and often lower caloric density by volume.
  • Surgical sterilization predisposes cats to weight gain for numerous reasons. Neutered male and female cats have resting metabolic rates 20 to 25% below those of intact cats of similar age. When a cat is discharged after surgical sterilization, new feeding recommendations should be calculated and explained to the client:
    • Feed lower calorie foods (if not a growing kitten) or restrict regular foods to 75% of the previous amount. Changes should be made over a period of 1-2 weeks to improve success.
    • Schedule an evaluation of body weight and BCS 4 to 5 months after surgery to ensure maintenance of ideal body weight and condition.
  • Muscle condition should also be evaluated. A muscle-wasted patient may be suffering from a catabolic disease (e.g., neoplasia, a protein-losing nephropathy or enteropathy), be unable to absorb dietary protein efficiently (e.g., intestinal disease), or may need a diet with more protein. Even an obese individual may be muscle wasted, making weight and BCS alone inadequate for assessing body condition.

Feeding Management

The domestic cat is anatomically and physiologically adapted to eating as many as 10-20 small meals (a reflection of their natural hunting behaviour) throughout the day and night. Feeding twice daily or having a bowl that is never empty are not “natural” ways for cats to eat. Having opportunities to express hunting behaviour is a basic need for cats. Allowing cats to ‘hunt’ for their food, or using a feeding device, are mentally stimulating activities. Examples of feeding devices are found under Resources.

Under stressful situations, many cats will refuse a novel food. Under other circumstances, the same cat may be adventuresome and choose a new diet over a familiar food. A new diet is more likely to be accepted if it is offered at home rather than in the clinic setting. Changing diets can be challenging; tips on transitioning to new diets can be found in the brochure from Hill’s Pet Nutrition, A Simple Guide to Feeding Your Cat.

After changing diets, a recheck appointment is needed (similar to rechecking after any other medical recommendation) to assess how this particular individual is responding to the recommended diet. In essence, when a new diet is recommended, you are performing a nutritional study involving one cat!


  • Susan Little, DVM, DABVP (Feline Practice) Bytown Cat Hospital, Ottawa, Ontario
  • Diane McKelvey, DVM, DABVP (Feline Practice) Aberdeen Veterinary Hospital, Kamloops, British Columbia
  • Elizabeth O’Brien, DVM, DABVP (Feline Practice) The Cat Clinic, Hamilton, Ontario
  • Elizabeth Ruelle, DVM, DABVP (Feline Practice) Wild Rose Cat Clinic of Calgary, Calgary, Alberta
  • Kelly St. Denis, MSC, DVM, DABVP (Feline Practice)
  • Margie Scherk, DVM, DABVP (Feline Practice) catsINK, Vancouver, British Columbia

    Please Note: Not all resources are available in both English and French.