Enhanced thermogenic response to a diet low but adequate in protein persists in older rats

Feeding a 5% lactalbumin diet to rats for 3 wk compared with a 15% lactalbumin diet resulted in lower feed efficiency and stimulated brown adipose tissue activity as measured by GDP binding. This occurred in 4-mo-old rats as well as in 7-mo-old rats. Furthermore the effects persisted after 3.5 mo of dietary treatment. An investigation of pattern of food intake revealed that no obvious alteration in pattern was involved in the lower feed efficiency associated with rats fed a 5% lactalbumin diet.