An experiment was conducted in the semi-arid temperate highlands of central Mexico (1994–95) with 12 adult, female non-pregnant, non-lactating, crossbred Nubian goats to determine the effects of 36 weeks of feed restriction on body weight, carcass composition and blood concentrations of glucose and hormones (insulin, triiodothyronine [T3] and tetraiodothyronine [T4]). After a 9-week feed intake, liveweight and body condition stabilization period, the animals were divided into three groups and individually offered either 100, 80 or 60% of their observed average daily consumption. Feed intake was measured daily, liveweight weekly, and blood-serum glucose and hormone concentrations every 4 weeks. At the end of the feeding experiment, the animals were slaughtered, and the carcasses and viscerae weighed. Liver and muscle samples were obtained and chemically analysed. Insulin and T4 did not differ between treatments (P>0·05). Final liveweight; blood-serum glucose and T3; carcass yield; muscle tissue dry matter, fat, RNA and RNA:protein ratios; hepatic tissue protein, RNA:DNA and protein:DNA ratios decreased, while liver and muscle DNA increased with restriction (P<0·05). These results suggest that capacity of goats to adapt to long term undernutrition and the importance of hepatic and muscle tissues as sources of metabolic energy.