The objective of the present study was to measure the differences in body composition, adipose tissue gene expression, blood metabolite and hormone concentrations, and insulin sensitivity in kittens exposed to high-protein (HP) or high-carbohydrate (HC) nutrition in utero and through the growth period. Eight dams were randomised onto two test diets, and fed the diets throughout gestation and lactation. Male offspring were evaluated for 9 months. Kittens were weaned at 2 months of age onto the same treatment diet as the dam and were allowed to consume diets ad libitum. The HC diet contained 34·3 % crude protein (CP), 19·2 % fat and 30·8 % digestible carbohydrate, while the HP diet contained 52·9 % CP, 23·5 % fat and 10·8 % digestible carbohydrate. Blood samples were collected at 6 months after birth. Body composition was determined at 2 and 8 months of age and an intravenous glucose tolerance test, neutering and adipose tissue biopsy conducted at 8 months of age. Physical activity was quantified at 6 and 9 months. Energy intake, DM intake and body weight were not different between groups. At 2 months, blood TAG were greater (P < 0·05) in kittens fed the HP diet. At 8 months, blood leptin was higher (P < 0·05) in kittens fed the HC diet, while chemokine receptor 5, hormone-sensitive lipase, uncoupling protein 2, leptin and insulin receptor mRNA were greater (P < 0·05) in kittens fed the HP diet. The present results demonstrate some of the changes in blood metabolites and hormones, physical activity and mRNA abundance that occur with feeding high protein levels to kittens.