Lately, I’ve been suffering from a sweet tooth – I can’t get enough chocolate to satisfy my “craving,” and grapes just aren’t cutting it. I know enough now to just keep it out of the house so I don’t have access to it, but it’s nice to know my “addiction” might be more based on biology and less on my lack of will-power. According to an article on Science Daily, scientists found the brain can sense caloric values of foods independent of taste mechanisms:
Their finding that the brain’s reward system is switched on by this “sixth sense” machinery could have implications for understanding the causes of obesity. For example, the findings suggest why high-fructose corn syrup, widely used as a sweetener in foods, might contribute to obesity.
In their experiments, the researchers genetically altered mice to make them “sweet-blind,” lacking a key component of taste receptor cells that enabled them to detect the sweet taste.
In analyzing the brains of the sweet-blind mice, the researchers showed that the animals’ reward circuitry was switched on by caloric intake, independent of the animals’ ability to taste. Those analyses showed that levels of the brain chemical dopamine, known to be central to activating the reward circuitry, increased with caloric intake. Also, electrophysiological studies showed that neurons in the food-reward region, called the nucleus accumbens, were activated by caloric intake, independent of taste.
Significantly, the researchers found that a preference for sucrose over sucralose developed only after ten minutes of a one-hour feeding session and that neurons in the reward region also responded with the same delay.
So I eat chocolate, my brain releases an amount of dopamine relative to the caloric value of the chocolate, and I inherently place a higher value on chocolate because of the pleasant feelings it invokes. It’s like someone designing our bodies knew we wouldn’t eat enough if there weren’t some biological prompting. Frankly, I don’t know if this is good news or not – it’s like I’m my body is biologically designed towards obesity! Or, at least, our current society, with all it’s abundant and ready access to high-calorie foods, warps our biological mechanisms.
At any rate, I just need to keep grapes in the house, and evict the chocolate.