Dietary fat and carbohydrate have different effects on body weight, energy expenditure, glucose homeostasis and behaviour in adult cats fed to energy requirement

Abstract

The effects of dietary carbohydrate and fat on feline health are not well understood. The effects of feeding diets moderately high in fat (HF; n 10; 30 % fat, 26 % carbohydrate as fed) or carbohydrate (HC; n 10; 11 % fat, 47 % carbohydrate), for 84 d, were investigated in healthy, adult cats (3·5 (sd 0·5) years). Data on indirect calorimetry, blood biomarkers, activity, play and cognition were collected at baseline, and at intervals throughout the study. Body composition was measured by dual-energy X-ray absorptiometry at baseline and on day 85. There were no significant main effects of diet on body weight and composition. When data were analysed over study day within diet, cats fed HF diets experienced a significant increase in body fat (P = 0·001) and body weight (P = 0·043) in contrast to cats consuming the HC diet that experienced no change in body fat or body weight (P = 0·762) throughout the study. Overall, energy expenditure was similar between diets (P = 0·356 (fasted), P = 0·086 (postprandial)) and respiratory quotient declined with exposure to the HF diet and increased with exposure to the HC diet (P < 0·001; fasted and postprandial). There was no difference in insulin sensitivity as an overall effect of diet (P = 0·266). Activity declined from baseline with exposure to both diets (HC: P = 0·002; HF: P = 0·01) but was not different between diets (P = 0·247). There was no effect of diet on play (P = 0·387) and cats consuming either the HF or HC diet did not successfully learn the cognitive test. Overall, cats adapt to dietary macronutrient content, and the implications of feeding HC and HF diets on risk for adiposity as driven by metabolic and behavioural mechanisms are discussed.

Carbohydrate level and source have minimal effects on feline energy and macronutrient metabolism

“…Similarly, the greater mean fed RQ in cats fed the high PGR diet implies increased carbohydrate oxidation compared with cats fed the medium or low PGR diets. This fluctuation of RQ with diet composition is consistent with the literature and indicates that lean healthy cats can adapt macronutrient utilization to alterations in dietary macronutrient intake (Hoenig et al, 2007;Gooding et al, 2015). Interstitial glucose concentrations of cats consuming 3 experimental diets differing in perceived glycemic response (PGR): high, medium, and low PGR, over a measurement period of 20 h. The PGR refers to the expected theoretical glycemic response that would result from consumption of each diet.…”

Identifying the target population and preventive strategies to combat feline obesity

“…Limited research has been conducted on the effects of macronutrient compositions after gonadectomy; however, consistent with previous reports in adult cats without gonadectomy as a factor, 104,105 gonadectomized cats of both sexes experience a positive correlation between BW and fat mass with increasing dietary fat content. 32,44 In both studies, cats were gonadectomized at 7–10 months of age, they were fed ad libitum and test diets were not formulated specifically for growth.…”

Digestibility Is Similar between Commercial Diets That Provide Ingredients with Different Perceived Glycemic Responses and the Inaccuracy of Using the Modified Atwater Calculation to Calculate Metabolizable Energy

“…Although current standards indicate that the domestic cat is an obligatory carnivorous species [ 1 ], felines have displayed the physiological capability to successfully metabolize multiple carbohydrate sources, and that high carbohydrate inclusion levels (35%) do not impair macronutrient digestibility [ 2 ]. Cats also exhibit a metabolic ability to alter macronutrient oxidation based on variable intake of carbohydrates and fats [ 3 ].…”

“…Consumers benefit from feeding kibble in terms of affordability, convenience, and assurance that their pets’ food will remain microbially safe for an extended period of time. Furthermore, cats fed diets high in carbohydrates are at a lower risk of adiposity and correlated negative metabolic outcomes compared to cats fed diets high in fat [ 3 ]. Though controversy exists regarding the impact of carbohydrates in feline diets, there is limited research investigating the mechanisms of carbohydrate digestion and metabolism in cats.…”