OBESITY: WINNING THE BATTLE OF THE BULGE
TAKES MORE THAN A BAG OF FOOD
Margie Scherk DVM, DABVP (feline practice)
Small Animal Track
2012 ISVMA Annual Conference Proceedings
Obesity is the number one nutritional disorder in pets in the western world. Twenty five
percent of cats seen by veterinarians in the USA and Canada are overweight or obese1.
Cats are no different than the rest of us, in that, over-consumption of calories results in
storage and is manifested as excessive body fat. In optimal condition, cats should carry 1520% body fat.
In another study in 1998, Scarlett and Donoghue2 looked at diet and obesity in cats. Using
multivariate statistical analysis controlled for age, they showed that obesity is a risk factor for
diabetes mellitus, skin problems, hepatic lipidosis, and lameness. A more general look at
the consequences of obesity or a chronic overweight state adds the additional risks in other
species as well as the cat: hyperlipidemia, insulin resistance, glucose intolerance, feline
lower urinary tract disease, anaesthetic complications, dyspnea, Pickwickian syndrome,
exercise intolerance, heat intolerance, impaired immune function, exacerbation of
degenerative joint disorders and dermatological conditions.3,-5 The longer a cat (or person) is
overweight, the greater the chance that one of the negative consequences of obesity will
occur.
Interestingly, mixed breed cats were found to be at higher risk for becoming overweight than
purebreds. This might be genetic, but husbandry and awareness of the cat may play a role.
Because we confine cats indoors, feed them highly palatable, calorie-dense diets (especially
dry food) which they do not have to work for, and leave them alone many hours a day,
possibly resulting in boredom, our cats are likely to consume excess calories.
Neutering has been shown to reduce the energy requirements (resting metabolic rate) of
cats by 20-25%.6,7 A link has been shown between weight and fat gain following
gonadectomy and serum leptin levels.8 It has also been shown that increased leptin levels
may contribute to the decreased insulin sensitivity (resistance) seen in overweight cats.9 In
fact, further work has indicated that insulin resistance and glucose intolerance develop in
obese cats and that this occurs at an increased incidence in male cats; interestingly, male
cats are at increased risk for developing diabetes mellitus.10
It is important, therefore, that we counsel our clients to change to an adult formulation and to
watch carefully for weight gain and adjust caloric intake accordingly. Ten extra pieces of an
average formulation kibble/day above a cat’s energy needs can result in a weight gain of one
pound of body fat in one year! So, the quantity we feed obviously can make a difference to
weight, but does the frequency of feeding? And research shows that the frequency of
feeding, as well as the quantity fed, makes a significant difference.10 Given innate feline
physiology, feeding cats small meals more often and limiting the number of treats offered are
the most appropriate feeding strategy, thereby assisting in weight loss.11,12
Fed optimally, cats reach their adult weight at about 12-15 months of age. This can be used
as a guide to determine a cat’s “ideal” adult weight.
Assessing Body Composition
It is easier to prevent weight gain than to help a cat lose weight. The prevalence of feline
obesity increases after 2 years of age, plateaus until about 12 years, and then declines
thereafter.13 Fed optimally, cats reach their adult weight and body condition score (BCS) at
about 12-15 months of age. This can be used as a guide to determine an individual cat’s
“ideal” adult size.
What tools do we have to help prevent the development of obesity? At every veterinary visit,
determining not only the patient’s body weight and recording it in their medical record, but
also calculating the percent weight change is an invaluable tool for the detection of weight
change patterns. Cats with early chronic illness may be identified using this calculation as
well.
% weight change = (current weight – previous weight) / previous weight.
Use a body condition scale (BCS) at every visit, categorizing subjectively, the body condition
as emaciated, thin, ideal, heavy or grossly obese (1-9 or 1-5 scale). This scale evaluates
contours and silhouettes. In ideal condition, the bony prominences of the body (i.e. pelvis,
ribs) can be readily palpated but not seen or felt above skin surfaces. There should be
insufficient intra-abdominal fat to obscure or interfere with abdominal palpation. Additionally,
assessing muscle condition using a muscle score, can also help define whether weight is
adequately proportioned to lean vs. to fat.
In questionable cases, radiographs and ultrasound may be used to assess falciform fat
deposits, paralumbar and perirenal fat. In research settings, dual energy X-ray
absorptiometry (DEXA) evaluation is used for the most accurate bone density, muscle mass
and fat calculations.
What To Feed
Simply feeding less of a normal diet is not recommended. Not only will the patient be
unhappy and feel hungry, but nutritional balance will be compromised. A diet should be
balanced according to energy content. When a cat eats enough of the diet to meet energy
requirements, then their protein, vitamin and mineral needs will be met, as well. An energylimiting diet is one, which is so energy dense that a cat will stop eating once energy needs
have been met but before protein and other nutrient needs have been met. Similarly, a bulklimiting diet will cause the individual to stop eating before energy and other nutrient needs
have been met.
Exceeding a cat’s protein needs beyond maintenance requirements helps induce satiety.
When they were fed a diet with 45% of calories from protein, cats lost more fat and less lean
mass compared with cats fed a diet with 35% of calories from protein, despite similar total
weight loss and rate of weight loss.14, 15
There are a number of approaches to feline weight loss:
1. High protein protects (minimizes loss of) lean mass, stimulates cellular energy
metabolism and protein turnover, and may enhance satiety.
2. High moisture can reduce caloric density, which promotes short-term weight loss: It
takes a few weeks to a few months for cats to adapt to the lower-caloric density (as
fed) in canned foods versus dry foods; however, this only works for some cats.
3. High fiber can reduce caloric density and induce satiety. Some cats will self-restrict
calorie intake when fed a dry, high-fiber, low-calorie diet.
4. Low fat will reduce caloric density. High-fat diets are a risk factor for inducing obesity
and are generally not considered optimum for a weight loss diet. That said, some cats
will lose weight on a high-protein, high-fat, low-carbohydrate diet if the calories are
restricted appropriately.
Ultimately, it is the calories ingested versus expended that is required for loss of weight.
Given the benefits of achieving lean body mass by feeding a high protein diet, a goal of at
least 40% protein, dry basis, in a low-fat diet (6% to 10% fat) or more protein in a higher-fat
diet (12% to 16% fat) is a healthy approach to take.
When discussing with clients why reduced quantities of normal foods won’t result in
successful weight loss, the following may be considered:
 Normal diets are too high in fat.
 Fat is an easy energy source for manufacturing.
 There is less thermic energy formed in the digestion of fat.
 Digestibility is inversely proportional to the amount fed.
 All nutrients are decreased when you feed less of a balanced diet.
An individual’s energy requirements are composed of several components. The daily
energy requirement (DER) = resting energy requirement
+ exercise energy requirement
+ thermic effect of food (TEF)
+ adaptive thermogenesis (AT)
Unlike metabolizable energy requirement (MER), DER includes energy required
for activity, such as work, gestation, and growth, as well as energy needed for
maintaining normal body temperature.
 Resting energy requirement varies with individuals; this accounts for the apparently
higher manufacturer recommendations vs. a given individuals food needs.
 TEF is the energy spent on digesting and absorbing food. Increasing the frequency
of meals and decreasing their size results in an increased TEF expenditure.
 AT is the energy used to regulate body temperature.
 DER decreases with increasing age.
A Clinic Weight Loss Program
In order to be successful with any weight loss program, three components must be in place:
diet, exercise and recheck visits. Without any of these, the clients desire for their cat to slim
down, will fail. A diet alone can’t do it as recheck visits monitor progress and provide
support needed by most people. Any exercise will help. We need to reduce the number of
calories consumed, and increase calorie use and metabolic rate (exercise). Exercising cats
could be seen as an oxymoron, however, some dedicated clients have even designed agility
obstacle courses for their cats. Their commitment is the fuel for the success of the program.
On the initial extended consultation, a comprehensive physical exam is performed to rule-out
concurrent medical problems. Baseline blood work may be advisable, depending on the age
and condition of the kitty. A detailed history is collected in order to become familiar with
current feeding habits and routines. Table 1 contains useful questions for this purpose.
Ask the client to keep a one-two week feeding journal in which everyone in the household
who gives the cat anything ingestible, enters the information. The amount of food as well as
exact type (brand) should be recorded. The client can be asked to make this diary before
the appointment and bring it along. The diet diary provides the material needed to
determine the caloric intake that the kitty has been receiving and gaining weight on. This
should be compared to the caloric allowance being recommended. As a rule of thumb, in
order to lose weight, a cat needs 60-70% of the calories required to maintain his/her ideal
weight. In other words:
1. determine/approximate ideal weight
2. calculate calories needed for ideal weight (wt in kg X kcal/kg/day)
3. multiply this number by 60-70%.
Example: Fluffy weighs 18.6 lb (8.4 kg) with a BCS of 9/9 and is currently being
fed 375 kcal day. The goal is 12 lb (5.4 kg) for a BCS of 5-6/9.
12 lb (5.4 kg) X 50 kcal = 271 kcal
Feed 60% to 70% X 271 kcal = 163 to 190 kcal/day
Weight loss of 6.6 lb (3 kg) will take at least 12 months
Discuss with the client the benefits of weight loss as well as the risks of chronic obesity.
Acknowledge them for their concern and praise them for their desire to take action. Be
supportive! They are the ones who will have to do the work.
Inform them of the current weight as well as the goal weight. (The goal weight, may be
higher than the „ideal“ weight; the goal is a healthy weight, not a runway model.) Discuss
with them the length of time this may take. A safe rate of weight loss is 1/4- 1/2 pound/month
(0.1-0.25 kg/month). This will help them stay on track. A weight loss of 10% to 15% is
realistic and attainable and will provide health benefits.
The thermic effect of food (TEF) is the energy cost of digesting and absorbing food. As
mentioned above, the TEF is higher when small frequent meals are fed, so feeding multiple
small meals is preferable to feeding one or two large meals. One way to incorporate this, as
well as give the kitty a little challenge (and exercise), is to divide the day’s food amount on to
6 or 7 small saucers and place them throughout the home as if it were a „treasure hunt“.
This means that kitty is less likely to gorge, has to look for more and has a higher TEF cost.
Discuss with the client why cats become overweight. The first thing to recognize is that pet
food manufacturers have to make diets extremely palatable, because that is how a
consumer judges how much their companion likes it and decides whether to buy it again or
not. This means that most cat foods are very energy-dense from fat, as fat is palatable for
cats. In addition, because it is convenient to feed ad libitum, cats snack all day on high
calorie kibble, and easily eat more than they need. Cats generally lack exercise, when
compared to the hunter that they are designed as. In the wild, they have to catch 10-20
small meals a day to survive! And, as already mentioned, an indoor environment is not very
stimulating; cats may eat out of boredom. Former strays may also have the fear-driven
instinct to gorge in case there isn’t another meal.
We may not be what we eat, but what we eat certainly shapes our biology and how we live!
Being obligate carnivores has affected everything about cats from their hunting behaviour to
their solitary eating of many small meals a day to the size of their stomach and their lack of
salivary amylase to their social structure. Cats naturally hunt for their food, yet the drive to
hunt is independent from the need to eat. Hence, feeding more food doesn’t stop them from
killing birds or mice, it merely makes them gain weight. On average, a cat needs 10-15
attempts before they are successful at killing prey; thus the drive to “eye, stalk, pounce and
kill” is permanently turned-on else a cat would starve. Given that the average mouse
provides about 30-35 kcal or energy, and a cat needs 50 kcal/kg ideal weight/day, the 5 kg
cat needs 250 kcal or 8 mouse sized portions/day. These meals are spread out throughout
the day, not all at one time. Both feeding twice a day or leaving a bowl that is never empty
are “unnatural” ways for cats to eat. Given that a 30 kcal meal is approximately 10 pieces of
an average maintenance dry food, even eating 10 extra pieces/day results in a 10% (1 lb)
weight gain/year. We also contribute to obesity by our need for interaction with our cats.
Cats (in general) interact with us frequently and (as mentioned) at a low intensity/casually.
We, on the other hand, generally, want fewer, more intense/focused periods of interaction
with them. We also feel rejected or like a bad provider if our cats don’t eat their food eagerly
and seek second helpings. Eating is not a social activity for cats. And, because their meals
are so small, we misunderstand and want them to eat more. We try more and more diets
until we have “evidence “ that they enjoy their food. And so we train them to ask for food
and they train us to respond to their boredom or other unmet needs by feeding them.
Opportunities to express hunting behaviour are a basic need for a cat. If a cat doesn’t have
the opportunity to hunt, toys which meet appropriate criteria are small (prey-sized), make
high-pitched squeaks or cheeps and move in a rapid, unpredictable fashion. The Indoor Pet
Initiative offers an informative piece on choosing the correct toy for an individual cat:
http://indoorpet.osu.edu/cats/basicneeds/preypref/index.cfm. Also, allowing them to hunt for
their food (bowl) or use a feeding toy is mentally stimulating. Examples of toys of this sort
include:
 FUNkitty Egg-Cersizer: (http://www.premier.com)
 Go!Cat!Go! Play-N-Treat balls
 Pipolino (http://www.pipolino.ca/eng/pipolino.html)
 Multivet Slim Cat (http://www.petsafe.net/Products/Feeders/SlimCat.aspx).
Some that are more like puzzles include:
 Cat Activity Fun Board (http://www.traininglines.co.uk/cat-activity-fun-board-3397-0.html)
 Stimulo cat feeding bowl (http://aikiou.com/)
BUT, there is more to obesity than energy in and energy expended. A more holistic
approach can provide a greater chance of success. We must also consider why the cat is
eating more. Is he bored? Is he not receiving enjoyable stimuli from other, more healthy
sources and is therefore eating? What other aspects of normal behaviour are not available
for him to participate in? How is he meeting his “hedonic budget”? Chronic stress (that may
be present in the indoor confined cat) results in neuroendocrine changes that predispose to
obesity.16
What drives the client? In a very interesting study Kienzle and Bergler17 found that the
“positive strokes” received and the behaviours of clients towards their cats differ with the
cat’s weight. To quote from the paper itself: “Thirty percent of owners of overweight cats
compared with 12% of owners of normal cats stated that they did not feel very happy prior to
acquiring a cat, and the cat was intended to console and encourage them. These results are
suggestive of 1) a closer relationship between overweight cats and their owners than
between normal cats and their owners, 2) more over-humanization of overweight cats than
of normal cats, 3) a potential role of overweight cats as a substitute for human companions.
“People with overweight/obese cats tend to underestimate their cat’s BCS, talk about
different things to their cats than do people living with cats of normal weight. Not
surprisingly, people with overweight cats were more likely to get positive feelings from
watching their cats eat whereas people with cats of normal weight spent more time playing
with their cats. While there was” no significant difference between the number of meals and
snacks and the type of food received by normal and overweight cats. The overweight cats
more often received fresh meat and kitchen scraps or various extra treats added to their
regular food”, and cats of normal weight were more likely to get moist food than obese cats.
Somewhat curiously, people with overweight cats were more interested in their own health
than clients with cats of normal weight and, in the reverse, the former considered preventive
care for their cat as less important than the latter group of clients.
So, in a cat’s weight, there is an element of meeting the hedonic budget for the person living
with the cat. Hence it is essential that we address the behaviour of the people living with
and feeding the cat! Encouraging alternative “strokes”, things that make the person feel
good about their interactions with the cat, such as play and feeling proud of achieving weight
loss goals are not to be taken lightly. Positive feedback from us, the veterinary team (the
outside environment) as well as self-generated by the client, are key elements to the
success of a weight loss program.
The behaviour modification required to make a weight loss program successful, needs all
key family members to play a role. Are there other forms of interaction that the client can
have with the kitty, other than feeding? Treats are the downfall of many a weight control
program. It is best if one person handles all of the feeding and others bond through other
means (catnip, combing, playing). As mentioned earlier, feeding multiple small meals as a
treasure hunt is beneficial. Developing a routine of playing with a “cat dancer” (a hand held
flexible wire with a toy on the end) several times a day will add interest and exercise to the
kitty’s life. The cost of the program might include a bag of catnip and
a cat dancer (toy).
Create a bar graph to maintain in the clinic computer and kitty’s medical record. Update and
send the updated graph home with the client at every visit as a good reminder of their
success.
19
18.5
18
17.5
17
weight in lbs
16.5
16
15.5
Ma 1 Ma
15
Ma
29
Ju
12
Ju
26
Weight Loss Program
Initial 40-minute consultation with DVM: comprehensive physical examination to rule out
medical problems
Evaluate feeding diary (minimum 1 week feeding diary)
Evaluate current feeding habits and routines
During the initial weight loss consultation, it is important to ask questions such
as these:
• What specific amounts and type of food (all, including treats) are fed to the cat?
Does the cat drink milk? Is he or she fed “people” food?
• Who feeds the cat’s regular meals? Do family members routinely feed treats
and table scraps?
• How often is the cat fed? Is the food measured?
• Does the cat nibble or gorge?
• Where is the cat fed?
• Does the cat receive any medications? If so, are the medications given in food
or with a treat?
• Is the cat indoor or outdoor? If outdoor, does he or she routinely hunt?
• What other pets are in the household?
• Do other pets have access to the overweight cat’s food?
• Does the overweight cat have access to the other pets’ food?
• What is the activity level of the cat?
• Are there any known stress factors in the home environment?
Calculate current caloric intake
Calculate recommended caloric intake: 60-70% of intake required for goal body weight (may
need to use 50% if very inactive)
Send home a “weight loss pack” with food samples (dry and canned) for kitty to choose
from.
Discuss:
realistic goals
risks of obesity
why cats become overweight
behaviour modification
Follow-up is the key to the success of any weight loss program! A technician or nurse
(program supervisor) should become the client’s “buddy” and be in charge of the follow-up.
No weight loss program is effective without follow-up!
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Week 1: support phone call
Week 2: 15 minute visit with program supervisor and veterinarian:
Weigh in (same scale)
Conversation about highlights, problems
Update graph
Every 2 weeks come in for weigh-in.
Update and send home graph.
After 4 months, a 15-minute visit with the supervisor is advisable because a plateau may
occur, and new calculations may be needed to promote further safe weight loss.
Included in the program cost is unlimited buddy phone support. The program lasts 6 months
and is renewable if necessary.
References
1. Scarlett JA, Donoghue S, Saidla, et al. Overweight cats: prevalence and risk factors. Int
J Obes Relat Metab Disord. June 1994;18 Suppl 1(0):S22-8.
2. Donoghue S, Scarlett JM: Diet and feline obesity. J Nutrition 1998; 128 (12 Suppl): pp
2776S-2778S.
3. German AJ. The growing problem of obesity in dogs and cats J Nutr. July
2006;136(7):1940S-1946S.
4. Appleton DJ, Rand JS, Sunvold GD: Feline Obesity: Pathogenesis and Implications for
the Risk of Diabetes, in Proceedings 2000 Iams Nutrition Symposium, pp 81-90.
5. Burkholder WJ, Toll PW: In Hand, MS, Thatcher, CD, Remillard, RL et al (ed): Small
Animal Clinical Nutrition (4th ed). Topeka, Mark Morris Institute, 2000, pp 401-430.
6. Biourge, V: Feline Nutrition Update. World Small Animal Veterinary Association
Congress, 2001.
7. Harper EJ, Stack DM, Watson TD, Moxham G: Effects of feeding regimens on
bodyweight, composition and condition score in cats following ovariohysterectomy. J
Small Anim Pract 42[9]: 433-8 2001
8. Martin L, Siliart B, Dumon H, Backus R, Biourge V, Nguyen P: Leptin, body fat content
and energy expenditure in intact and gonadectomized adult cats: a preliminary study. J
Anim Physiol Anim Nutr (Berl) 85[7-8]: 195-9 2001
9. Appleton DJ, Rand JS, Sunvold GD: Plasma Leptin Concentrations Are Independently
Associated with Insulin Sensitivity in Lean and Overweight Cats. J Feline Med Surg 4[2]:
83-93 2002
10. Chastain CB, Panciera D: Insulin Sensitivity Decreases with Obesity, and Lean Cats with
Low Insulin Sensitivity Are At Greatest Risk of Glucose Intolerance with Weight Gain.
Sm Anim Clin Endocrinol 12[2]: 9-10 2002 discussion of Appleton DJ, Rand JS, Sunvold
GD: J Fel Med Surg 2001; 3:211-228
11. Russell K, Sabin R, Holt S, et al. Influence of feeding regimen on body condition in the
cat J Small Anim Pract. January 2000;41(1):12-7.
12. Michel, KE: Feline Nutrition: Fundamentals and Clinical Relevance. ABVP Symposium,
2002.
13. Michel, KE: Weight Reduction in Cats: Great Frustrations in Feline Nutrition. World Small
Animal Veterinary Association Congress, 2001.
14. Laflamme DP, Hannah SS. Increased Dietary Protein Promotes Fat Loss and Reduces
Loss of Lean
Body Mass During Weight Loss in Cats. Intern J Appl Res Vet Med; 2005: 3 (2): 62-86.
15. Cupp CJ, Jean-Philippe C, Wendell W. Kerr WW, et al. Effect of Nutritional Interventions
on Longevity of Senior Cats. Intern J Appl Res Vet Med; 2006: 4(1): 34-50.
16. Buffington CAT. External and internal influences on disease risk in cats. J Am Vet Med
Assoc. April 2002;220(7):994-1002.
17. Kienzle E, Bergler R. Human-animal relationship of owners of normal and overweight
cats. J Nutr. July 2006;136(7 Suppl):1947S-1950S.
http://jn.nutrition.org/cgi/content/full/136/7/1947S - TBL5