It’s in our genes! It’s in our genes! So says the most recent study of genetics and obesity. Shortages in AMY1 lead to an eight-fold increase in obesity risk. So if you have low AMY1, it’s just not your fault.
Well, it may not be that simple. According to other studies, different cultures have adapted to a high starch diet vs. a low starch diet. Notice we’ve changed carbohydrates to starch, which is important because low AMY1 folks can still digest simple sugars like, well, sugar. The number of AMY1 copies varies across populations, and may well correspond with some of the obesity we’re seeing but nowhere near the whole amount.
We’ve also got to ask some questions about the activation of this particular gene as it relates to saliva and amylase, the enzyme that breaks down carbohydrates. According to one study: “hydration status, psychosocial stress level, and short-term dietary habits” directly affect AMY1 activation and amylase production.
So here’s a different idea: people hork their food. I’ve already written that this could lead to anemia (here). If you have low AMY1 genetically, you already don’t have enough enzymes to break down your carbohydrates, which then ferment in your gut and lead to increased obesity (on gut bugs and obesity here). If you have enough AMY1, then you get more of a horking pass, and don’t gain weight as easily.
The effect of AMY1 could easily be checked by having low AMY1 individuals fully chew (saturate with amylase) their carbohydrates before swallowing. The same effect would explain why other cultures are not gaining weight as quickly as the American “I never eat my hot dog in more that two bites” overweight.
It’s enough to make me want to slow down next time I grab some bread.