Ponderostat: hoarding behavior satisfies the condition for a lipostat in the rat

The mass of food hoarded by rats given access to food only two hours per day is proportional to the rats' body weight deficit. The present work investigated whether this behavior might reflect the amount of body fat rather than body weight. The hoarding behavior of three rats was measured every other day at various body weights. After each hoarding session the animals were anesthetized and their percentage of fat was measured in vivo with a total body electrical conductivity method (TOBEC). The results showed that the amount of food hoarded in the two-hour sessions was inversely proportional to the fat content of the body. This result shows that, in the rat, the fat stored is correlated with the behavioral response leading to the defence of body weight, and therefore satisfies a condition necessary for a lipostat.