Page 929 - Small Animal Internal Medicine, 6th Edition

CHAPTER 51 Weight Loss and Obesity 901

but disruptions in the regulation of food intake appears quantitative information concerning alteration in fat-free or
to be the most important effect. This apparently occurs lean body mass relative to fat mass.
VetBooks.ir rapidly, and increased food intake occurs almost imme- abdomen, hip, thigh, and upper arm are commonly used to
Height and circumferential measurements of the
diately after neutering. Obesity has been reported to be
more common in female neutered dogs and male neutered
phometric) measurements have also been developed to esti-
cats, and greater gains are seen with free-feeding. As such, estimate the percentage of body fat in humans. Body (mor-
portion control is critically important to avoid weight gain mate the percentage of body fat in dogs and cats. These tools
after neutering. have been promoted as one way to estimate ideal body
Obesity is less likely to result from a disease process or weight to provide guidance for determining the amount to
drug. Indeed, it has been suggested that less than 5% of feed for weight loss plans. However, successful weight loss
obesity is due to a disease or drug. Endocrine abnormalities plans utilizing morphometric measurements to estimate
associated with obesity include hypothyroidism, hyperadre- ideal body weight have not been reported in the literature.
nocorticism, hyperinsulinism, and acromegaly. Drugs such Studies have demonstrated that proportion of body fat as
as progestagens and corticosteroids have been associated estimated using BCS systems correlates well with that deter-
with the development of obesity. mined by DEXA measurements in both dogs and cats.
However, marked individual variability was reported when
Diagnosis using a 5-point BCS system to estimate ideal body weight in
Obesity is defined as a “pathological condition characterized dogs (German et al., 2009). Very few clinical settings can
by an accumulation of fat much in excess of that required for access more precise and validated measures of body compo-
optimal body function” (Mayer, 1973). However, what is an sition to more accurately estimate ideal body weight (such
excess amount of body fat, and what is an acceptable amount? as DEXA). Regardless, providing an approximate quantita-
To answer these questions, the clinician must accurately tive assessment of a patient’s degree of adiposity can be
determine the amount of body fat. Body fat can be assessed helpful in diagnosing obesity even if not exact (using either
by techniques such as morphometric measurements, dilu- morphometric measurements or BCS or both). Ultimately,
tional methods, bioelectrical impedance analysis, dual focusing the owner on the process rather than the end goal
energy X-ray absorptiometry (DEXA), densitometry, com- may be warranted, given that measurable benefits are seen
puted tomography, magnetic resonance imaging, determina- with weight loss even before the target ideal body weight is
tion of total body electrical conductivity, determination of achieved.
total body potassium, neutron activation analysis, and mor-
phometric measurements. Although numerous methods Treatment
may be used to determine body fat, the most clinically useful After diagnosing a patient as overweight or obese, the clini-
techniques in small animal practice include measurement of cian should obtain a thorough dietary history to calculate the
body weight and determination of a BCS. patient’s daily caloric intake. The clinician should gather the
Measurement of body weight is a standardized, simple following information:
technique and should be included in the examination of
every animal. However, body weight does not provide • Name, manufacturer, and type (i.e., wet versus dry, etc.)
information regarding body composition, so additional of the current food(s)
assessments are necessary. Consideration of the potential • Amount of food that is fed each day (pouches, cans, cups,
contribution to absolute body weight of excessive adipose, or grams of food)
decreased muscle mass, and fluid accumulation may be war- • Method of feeding (ad libitum versus meal fed)
ranted in many cases. • Person responsible for feeding the pet
Body condition scoring provides a quick and simple sub- • Additional persons who may feed the patient (children,
jective assessment of the animal’s body condition based on elderly parents, or neighbors)
estimates of stored body fat (adipose tissue). It does not • Number and types of snacks, treats, or human foods given
include assessment of lean body mass, and muscle condition each day
scoring systems are distinct from BCS systems. The two most • Type and amount of any supplements given each day
commonly used BCS systems in small animal practice • Potential access to other foods (for other pets, from the
include a 5-point system in which a score of 3 is considered garden, etc.)
ideal, and a 9-point system in which a score of 5 is consid-
ered ideal for cats and 4 or 5 is considered ideal for dogs The patient’s current body weight should be recorded and
(Figs. 51.1 and 51.2). Larger numbers are used for patients a BCS assigned. Body weight trends should be considered as
with greater adiposity. Each point above ideal on the 9-point well (is the patient gaining, stable, or losing). The BCS can
system approximates a body weight 10% to 15% over ideal. be used to determine the percentage of body weight that
Thus a feline patient that has a BCS of 7 out of 9 is 20% to must be lost. Because each point above ideal on a 9-point
30% overweight as a result of the accumulation of adipose scale represents an additional 10% to 15% of weight over
tissue. The BCS technique is subjective as it depends on ideal, the clinician can calculate the percentage of weight that
operator interpretation and does not provide any precise should be lost. For example, an otherwise healthy feline