When presented with food that doesn't contain the right amount of essential amino acids, an animal will stop eating within 20 minutes and look for something else that does contain those building blocks of protein. Scientists have watched this behavior for years but could never explain why it happened, until now.
Scientist tracy anthony studied how a gene that's abundant in the brain called gcn-2 affected the feeding response in mice. One of these tiny creatures is normal. The other is genetically altered so that gcn-2 is missing from its brain. When presented with a diet deficient in amino acids, the normal mouse had a normal reaction. It stopped eating within twenty minutes. The genetically altered mouse was unable to detect the deficiency in the food and kept eating.
Tracy anthony, ph.d./asst. Professor biochemistry: "now that's not compatible with survival. If you continue to eat a diet that doesn't have your full complement of amino acids, you will quickly decline in health."
the journal "science" published the findings because for the first time, they show a gene determines protein intake. Not just for mice, but for every species from a single cell of yeast all the way to humans. So doctor anthony's work may someday have applications in treating the anorexic or the obese.
Dr. Anthony: "what this says is that there is potential for mechanisms in the brain that control our eating behaviors in amount, in our inability to stop eating, in our ability to eat certain foods, that there are likely other mechanisms besides just tasting good or looking good."
this particular mechanism guides food selection for survival, but what guides it overall isn't so simple.
Dr. Anthony: "so this is one layer, but there is the psychological layer. There is the biological layer. There's the neurological layer and there is all these inputs that help us decide what's our meal choice of the day."
but it's an exciting layer, a discovery that can only be built upon from here.))
a separate group of scientists have repeated doctor anthony's experiment and come up with the exact same conclusion.
Their study was just published in another scientific journal this week.
So this may explain why we have some cravings?