was particularly limited.
Nonetheless, Keys’s observations became the basis of
the “grain-based” Mediterranean dietary pattern, ultimately
informing the development of the highly influential Food
Pyramid, which advised consumers to eat less fat and load
up on grain products—up to eleven servings per day. (The
Food Pyramid’s successor, the USDA MyPlate, still advises
consumers to include grains at every meal.) Food
manufacturers didn’t object, taking advantage of hefty grain
subsidies. But did Keys attribute the health effects of the
Mediterranean diet to the wrong food group?
When looking at population data, one might notice that
the intake of whole grains is certainly associated with less
diabetes, colon cancer, and heart and brain disease. People
who consume mostly brown rice, whole-wheat bread, and
highfalutin grains like quinoa tend to make better choices
elsewhere in their diets.^1 They may eat more wild fish (rich
in omega-3s), extra-virgin olive oil, and vegetables and far
fewer of the refined carbs and Franken-oils that are
characteristic of the Western diet. They also live healthier
lifestyles in general and tend to exercise more.^2 But at this
bird’s-eye view, it is impossible to isolate the health effects
of grains in an overall healthy diet. Still, the idea that whole
grains improve health has become, for lack of a better term,
ingrained. (They have even been grandfathered into modern
“spin-offs” of the Mediterranean diet, such as the
government-endorsed DASH diet to reduce high blood
pressure.)
In this chapter, as we explore the role of an ancestral
hormone called insulin in brain function, we’d like you to