Obesity Hypothesis

Previous posts have asked why obesity would appear in America only in the past 15 years, when we’ve had the gustatory trappings of success for many decades. A related question is why slim parents would have fat kids. What changed 20 years ago?

Here is a theory.

It turns out the insulin response is part of fetal development. The LA Times reported today that babies are twice as likely to be obese adolescents if the mother was diabetic during pregnancy. In effect, the unborn baby is at the tail of the insulin whip, responding much more strongly than the mother to overexposure to blood sugar.

But the medical definition of diabetes is a rather arbitrary numerical cutoff. Instead, consider the more basic conclusion, that routinely elevated blood sugar in a pregnant mother creates a magnified effect in the unborn child, as the baby’s insulin response is desensitized.

Now consider three changes that occurred in the past 30 years. First, the federal government began to advocate that carbohydrates be consumed at much higher levels relative to fat and protein, compared to the prevailing American diet. Second, corn syrup was widely substituted for cane sugar (corn syrup hits the bloodstream faster than sugar, placing greater strain on the insulin system). Third, snack foods, largely sweetened with corn syrup, were consumed in much larger quantity as mother stopped cooking and Big Gulps proliferated.

The effects might not immediately be visible, since the adult has a functioning insulin response that predates the dietary change; the problem might emerge only in the children.

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