The aim of this study was to determine the metabolic response in giant pandas (Ailuropoda melanoleuca) to the consumption of certain parts of bamboo above ground growth. Giant pandas were provisioned with three species of bamboo: Phyllostachys bissetii, of which they only consume the culm (culm group); Bashania fargesii, of which they only consume the leaves (leaf group); and Qiongzhuea opienensis, of which they only consume the shoots (shoot group). The “culm” group absorbed the highest amount of calories and fiber, but was in short energy supply (depressed tricarboxylic acid cycle activity), and high fiber level diet might reduce the digestibility of protein. The “culm” and “leaf” groups absorbed less protein, and had a lower rate of body mass growth than the “shoot” group. Digestion of fiber requires energy input and yields low caloric extraction from the culm and leaf, and protein intake is important for increasing body mass. However, long-term consumption of shoots may have a potentially negative effect on the health because of high protein composition. Therefore, a balanced diet consisting of diverse plant parts of bamboo is important for the overall metabolic function and health of captive giant pandas.