Fatty and sweet foods hijack the brain

The genius of humankind has combined fats and carbohydrates to produce such crowning culinary glories as the doughnut, fettuccine Alfredo, nachos and chocolate cake with buttercream frosting.

It goes without saying that these delectables do not exist in nature. It turns out combinations of carbohydrates and fats generally do not exist in the landscape in which man evolved.

Neither, new research finds, does the human capacity to in- tuit the caloric content of such gustatory delights. Instead, the human brain, when confronted with food products that combines fat and carbohydrates, responds with a surge of motivation that outstrips the response elicited by foods that are high in fat only or in carbohydrates only.

It’s a man-made conundrum like many others, and which probably has helped fuel a worldwide crisis of obesity: What do we do when the products of our genius and our industry short-circuit our evolved traits and lead us down a path of destruction?

The study just published in the journal Cell Metabolism doesn’t really tell us something we didn’t at some level know: We eat too much, and too much of the wrong thing, and we’re paying the price in higher rates of heart disease, diabetes and cancer, and in lives shortened by obesity.

But it does shed some light on why, and why we find everything from the dowdy Ritz cracker to the most sublime pastry confection so very irresistible: It’s that diabolical combination of fat and carbs. Calo- rie for calorie, it found, we’ll take something fatty and easily converted into sugar over something that’s just fatty or something that’s just high in carbs. And we’ll do so with scant recognition of just how caloric that choice is.

So long as concoctions that combine fat and sugar call out to us from food shelves, television screens and menus, we’re vulnerable to our most primal instincts, which have not evolved to say no to these products of human invention.