Page 502 - Small Animal Clinical Nutrition 5th Edition

518 Small Animal Clinical Nutrition

VetBooks.ir Table 27-6. Key nutritional factors for metabolic-control cat carbohydrates should not exceed 20% (DM); lower is probably
For metabolic weight-loss foods for cats, dietary digestible
foods for weight loss.
better. When foods containing this level of dietary carbohy-
Factors Dietary recommendations (dry matter basis) drate in combination with increased protein and moderate fat
Carbohydrate ≤20% are fed in appropriate amounts, they result in controlled weight
Protein At least 47% but not exceed 55% a
Fat ≤25% loss in cats (Butterwick and Markwell, 1994, 1996).
Fiber ≥5%
L-carnitine ≥500 ppm Protein
Antioxidants Foods for weight loss and prevention of weight
regain should contain: Cats have an innate metabolic capacity to readily use protein
Vitamin E ≥500 IU vitamin E/kg (amino acids) for energy (Chapter 19). The natural diet of cats
Vitamin C 100 to 200 mg vitamin C/kg is primarily animal tissue and contains only small amounts of
Selenium 0.5 to 1.3 mg selenium/kg
Sodium Foods for weight loss should contain between digestible carbohydrate. Cats, therefore, typically have lower
0.2 to 0.6% levels of hepatic glucokinase than do omnivorous species and
Phosphorus Foods for weight loss should contain between have higher levels of transaminases and deaminases that do not
0.5 to 0.8%
down regulate, even when protein intake is reduced. Thus, cats
have a higher protein requirement and are metabolically geared
to use protein for energy. Cats rely heavily on glucogenic amino
restricted foods, simple sugars and complex carbohydrates (i.e., acids to generate glucose for glucose-dependent tissues
grain sources) have received much attention in human weight- (Macdonald et al, 1984) (Chapter 19).
loss programs because of the known effects of various carbohy- Increasing its protein content can reduce the carbohydrate
drates on the glycemic index. As in people, consumption of dif- content of a food. As discussed for the key nutritional factors
ferent sugars and carbohydrate sources alters postprandial glu- for the energy-restriction approach to weight loss, relying on
cose levels and insulin secretory patterns in cats and dogs dietary protein as a major energy source has beneficial meta-
(Flickinger and Sunvold, 2005; Bouchard and Sunvold, 2000; bolic effects for weight loss. These effects include reduced
Nguyen et al, 1998; Sunvold and Bouchard, 1998). Therefore, energy efficiency, satiety effects and preservation of lean body
foods producing low glycemic responses should be recom- mass.
mended for obese or diabetic patients. In people, increasing a food’s protein content increases its
The stimulatory effect of increased carbohydrate intake on thermic and satiety effects (Crovetti et al, 1998). The TEF is
insulin secretion provides for a metabolic shift to support fat the obligatory cost of digesting and absorbing food. TEF con-
deposition, given the potent lipogenic effects of insulin. In con- stitutes approximately 10% of total expenditure. Thus, increas-
trast, low-carbohydrate foods, particularly in combination with ing a food’s thermic effect reduces its energy efficiency
fat, protein and fiber, result in a more blunted insulin response (Danforth, 1985; Horton, 1983). In a human study, 10 people
that helps set the stage for fat use. Also, as discussed above, by received, in randomized order, high-protein, high-fat and high-
using less available carbohydrate sources, the glycemic index carbohydrate meals.The high-protein meal was the most ther-
can be modified to further shift energy use to be more depend- mogenic (p <0.001) and it determined the highest sensation of
ent on amino acids (protein), fat and ketones. Furthermore, in fullness (p = 0.002). There were no differences in the sensation
the calorie-restriction approach to weight loss, different sugar and thermic effects between the high-fat and high-carbohy-
and starch sources variably affect postprandial glucose levels drate meals. A significant relationship linked TEF to fullness
and insulin secretory patterns in cats (Bouchard and Sunvold, sensation (r = 0.41, p = 0.025) (Crovetti et al, 1998).
2000). Carbohydrate sources that result in a lower glycemic Increasing the dietary protein level during weight loss
index are more desirable for metabolic weight control. spares lean body mass. In one study in cats, 47% DM dietary
Compared to barley, corn and sorghum, rice as a starch source crude protein preserved lean body mass during controlled
produces the highest glycemic index in cats. Therefore, as with weight loss (1% per week). In this study, weight loss did not
energy-restricted foods, it is probably best if rice is not one of differ significantly between cats fed a high-protein food and
the first three or four non-water ingredients on the product’s those fed a control food with less protein. However, the high-
label (Chapter 9). protein group had significantly greater loss of body fat and
A reduced ratio of dietary carbohydrate to protein in people significantly less loss of lean body mass (Laflamme and
has a satiety effect (Layman et al, 2003). Lowering the glycemic Hannah, 2005).
index could have an effect on satiety because a rapid increase in Theoretically, prolonged, excessive protein intake poses
blood glucose typically evokes an equally intense insulin some risks. Consumption of high-protein diets in people (i.e.,
response that can lead to a period of hypoglycemia followed by two to three times the U.S. Recommended Daily Allowance)
hunger. In people, this occurs approximately two hours after a increases urinary calcium loss and may, over time, predispose
meal (Roberts, 2000). However, increasing protein can also to bone loss (Eisenstein et al, 2002). However, cats have a rel-
have a satiety effect (see below). The satiety effect of a reduced atively high protein requirement because of their obligatory
dietary carbohydrate to protein ratio may be due to both com- use of amino acids in gluconeogenesis (Chapter 19) and are
ponents. well adapted to using dietary protein. The protein require-