The objective of this study was to examine the effect of diets high in either carbohydrates or protein on substrate oxidation and energy expenditure in lean and obese cats before and after weight reduction. Twelve lean (six females and six males) and 16 obese (eight females and eight males) adult neutered purpose-bred cats were used. The cats were evenly allocated to two groups and randomly assigned diets (diet X: high carbohydrate, low protein; diet Z: low carbohydrate, high protein). Each diet was fed for 4 months, and then the diets were switched. After 8 months, obese cats were maintained on the same diet they had been fed during the preceding 4 months; however, their food intake was decreased to obtain an approximate 1.5% decrease in body weight per week. Indirect calorimetry was used to examine respiratory exchange ratio (RER) and heat production in the fasting state and after food intake after 4 and 8 months and 6 months later when the cats had returned to their original lean weight. Fasting RER values were highest in lean cats on diet X and lowest in calorie-restricted cats on either diet. After food intake, lean cats fed diet X oxidized more carbohydrates than lean cats fed diet Z (RER: 0.89 ±0.02 and 0.84 ±0.01, respectively), and calorie-restricted cats oxidized more fat than lean cats (P < .03). Fasting and postprandial RERs of obese cats did not differ by diet. In lean cats, 24-hour and dark-cycle heat production were higher on diet Z than on diet X (P < .05 and P < .005, respectively). No dietary effect was seen on heat production in obese cats or calorie-restricted cats. This study showed that lean cats adapt to a varying dietary carbohydrate content. A low-carbohydrate, high-protein diet has beneficial effects on energy expenditure.
|Original language||English (US)|
|Number of pages||1|
|Journal||Compendium on Continuing Education for the Practicing Veterinarian|
|Issue number||4 SUPPL.|
|State||Published - Apr 2006|
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