Thanksgiving kicks off the unofficial, waistlines-be-damned season of gluttonous indulgence that will stretch right through to New Year's, when we'll collectively resolve to undo what we just did to our bellies.
It's harmless enjoyment of tasty holiday fare, right? If it is done in moderation. Problem is, moderation usually gets thrown out the window well before we even reach for the gravy, let alone drop a boulder-sized scoop of ice cream onto a piece of apple pie.
It's practically built into the idea of Thanksgiving that we should overdo it. Look at all this bounty! Show how grateful you are for it by tucking into a second helping, maybe even thirds.
But all that overdoing it, even briefly, can have a lasting impact on your body, mood and brain. A raft of studies published in recent years has highlighted the harmful consequences of piling our plates high, which go well beyond consuming too many calories.
In fact, scientists have found that overeating sets off a wide range of physiological effects. These include everything from triggering the same actions in the brain as illicit drugs, to elevating cholesterol levels months after a period of gorging, to helping to explain why you're sneaking down to the kitchen hours after you just stuffed yourself. So you might want to think twice before going for seconds.
Overeating changes your body clock. Mice fed a high-fat diet will wake up and chow down, scientists have found, which may explain those late-night cravings.
Fatty, salty, sugary foods alter your brain chemistry the same way cocaine does. They trigger the brain's production of dopamine, a feel-good neurotransmitter. A 2010 study in Nature Neuroscience found lab rats fed a poor diet exhibited similar characteristics of animals addicted to heroin and cocaine.
Overeating can make you stressed and depressed. A 2012 study found mice fed a high-fat diet had elevated levels of corticosterone, a stress hormone, and exhibited "pro-depressive effects," the Montreal researchers said.
Overeating for even brief periods can have permanent effects on body composition. In 2010, Swedish researchers found that a four-week binge by a group of normal-weight people resulted in them having gained an average of 3.3 pounds and higher LDL cholesterol levels - even a year later.
Desserts rich in fructose, such as donuts and apple pie, can keep a binge going. A January study in JAMA that compared glucose and fructose found that fructose increased the amount of blood flowing to the brain's hypothalamus, signalling the person was still hungry.
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