Results showed that prolonged exposure to high-protein diets does not alter DIT, and suggests that it is under acute regulation and not involved in adaptive thermogenesis
, or a sustained increase in metabolism.
Now, researchers propose that the largest contributor to adaptive thermogenesis is increased concentrations of pollutants in the blood, rather than changes that weight loss seems to trigger in the dieter's hormones.
They found that the measured adaptive thermogenesis was more strongly linked with the pollutants than with the natural hormone.
Rudolph Leibel, an obesity geneticist at Columbia University, points out that the new study offers merely a correlation, rather than proof that high blood concentrations of pollutants underlie adaptive thermogenesis.
PGC-1a is a co-activator of PPAR-g and regulator of adaptive thermogenesis
When cold, the body switches on adaptive thermogenesis in brown fat and in skeletal muscle cells, but what controls the mechanism is poorly known, notes Bruce M.
Since adaptive thermogenesis helps animals tolerate cold, the researchers hypothesized that whatever genes regulate the heat-generating process would become active when an animal was kept cold.
To test how PGC-1 influences adaptive thermogenesis, the researchers inserted a turned-on copy of the gene into white fat cells, which store excess calories.