Distinguished from the traditional Caloric theory which treats heat as substance without mass, the thermomass theory treats heat as a flux of substance with mass.
At UC Berkeley, Timiras studied the effects of caloric restriction on various hypothalamic nuclei, specifically the effects on cell density, estrogen receptor alpha immunoreactivity and insulin-like growth factor-1 (IGF-1) receptor immunoreactivity.
Leonard P. Guarente is recognized as the leading proponent of the hypothesis that caloric restriction slows aging by activation of Sirtuins.
A commonly used estimate of the thermic effect of food is about 10% of one's caloric intake, though the effect varies substantially for different food components.