Anyone who has teenagers, or was once a teenager herself, knows what a nuisance acne can be. Who hasn’t anticipated going out on a date at age 17, only to have a red hot zit spring up right on the tip of your nose?

It ain’t rare. Judging by the American experience viewable by a trip to your friendly neighborhood McDonald’s, acne is ubiquitous and inevitable, affecting 95% of 16- to 18-year olds. Even adults are not spared, with 50% continuing to have intermittent struggles. Then why do primitive cultures have zero acne? The New Guinea Kitavans and northern Canadian Inuits, for instance, had no acne–until the introduction of Western foods.

So what is it about the Western diet that makes for postponed dates and Clearasil cover-ups?

Any food that increases insulin also triggers something called insulin-like growth factor-1, or IGF-1, in skin. This stimulates sebum production, as well as growth of hair follicles and other cells in the dermis. The subterranean turmoil caused by increased IGF-1 erupts to the surface as the familiar pimple.

Simple logic: Any food that increases blood sugar also triggers insulin, thereby triggering IGF-1. So foods that trigger blood sugar and/or insulin the most are the most likely to cause acne.

So what familiar food increases blood sugar higher than table sugar, higher than a Milky Way bar, higher than a Snickers bar? Yup, good old wheat–whole grain, white, multigrain; bagel, muffin, wrap; donut, Twinkie, cupcake–makes no difference, it’s all the same. (Interestingly, dairy products do not increase blood sugar much, but they have a unique insulinotrophic effect, a tripling of insulin output by the pancreas, thereby increasing IGF-1 by a different route than wheat.)

So, better than Clearasil, tretinoin, or (highly-toxic) Accutane, is elimination of the foods that increase IGF-1. First step: elimination of wheat.