45WHAT TO MAKE OF CALORIES:
FOR HEALTH
M
uch ink has been spilled on whether “a calorie is a cal-
orie,” meaning whether your body treats one calorie
differently over another depending on its source, i.e.,
what food it comes from. The short answer is that the dis-
tinction does not matter on a cellular level, but it matters very
much on many other levels.
To understand what calories are, exactly, I like the expla-
nation given by Dr. Walter Willett in his book Eat, Drink, and Be
Healthy: “The amount of energy a particular food can deliver
to mitochondria—the tiny engines that power your cells—is
measured in calories.” So, basically, they’re like gas in the tank.
The bodies of most people eating a mix of foods convert carbo-
hydrates, fats, and protein to energy at the same rate. Calories
keep us in forward motion. Or as my summer camp counselors
trained us to sing cheerfully at dawn, they keep us alive, awake,
alert, enthusiastic!
But aside from the essential task of providing energy, food
is, of course, far more than fuel. And there are important ways
in which calories are different from each other, meaning the
equation for nutrition and health goes well beyond the simple
math of energy in, energy out. As with most things in life, cal-
ories are about both quality and quantity.
In general, calorie quality is more important than just the
number in isolation. Where the calories come from translates
into more or less nutritional bang for your buck. You might get
only 100 calories from a serving of cold cuts on a sandwich,Stuff that Comes from Factories 189Conscious Eater_03 PT_4th patches.indd 189 10/23/19 1:35 PM