a calorie is a calorie, mostly
David Katz wrote an article at eat + run called Fathoming the Calorie, and I couldn't agree with him more. I'm going to pull in quotes from his article below, along with my own comments..
a calorie is a precise and specific unit of energy, or heat. Namely, it is the heat required to raise the temperature of 1 cubic centimeter of water at sea level 1 degree Celsius. The measure we more routinely apply to food, the kilocalorie, is exactly 1,000 times as much. This is not up for debate, yet we seem bogged down in debating it—which is what I can't fathom.
Perhaps the answer is all around. Epidemic obesity is all the evidence we need that our relationship with the calorie has changed radically in modern times. For all of prior human history, the calorie was that precious thing we needed and had trouble getting in adequate supply. We loved the calorie!
Now the calorie is the thing we get too much of and can't seem to avoid. This would seem a basis for resentment, if not disgust. And perhaps this relatively sudden change in our relationship with the calorie compels us to wonder if the calorie itself has changed.
There's also the fact that the calorie seems capricious. Any two of us may eat comparable numbers of them, and one of us gets fat, while the other stays thin. Something fishy is surely going on there!
So, for most of our human history, we worked hard (physically) and ate as a means to refuel our bodies. Now, recently, we're sitting at our desks and eating gigantic double bacon cheeseburgers for pleasure. And we're blaming the calorie?! These are probably the same people who blame the school when their child fails or who want every kid to get a trophy just for playing. Come on, people, it's not that hard - eat less than you burn (a calorie deficit), and you lose weight. Period.
The quantity of calories we consume matters and it's the principal determinant of what we wind up weighing. The relationship between energy and matter is fixed well above the pay grade of New Age nutrition writers. The evidence that quantity matters is clear, consistent, and in my view, irrefutable. Fed an excess of calories, even if mostly from high-quality protein, people gain weight. Assigned to a calorie deficit, people lose weight—even if the calories are mostly from Twinkies. Calories count.
But of course, quality matters too, and it matters on both sides of the energy-balance equation.
Calories go out in three ways: we burn them to survive (resting energy expenditure); we burn them to work (physical exertion); and we waste them (thermogenesis or heat loss). The quality of the fuel we consume can affect both resting energy expenditure, and thermogenesis. Is this surprising? Not at all. We can make fire with wood, or coal; coal burns hotter. Protein, fats, and low-glycemic foods seem to burn a bit "hotter" than simple and refined carbohydrates, a fact corroborated by a recent study in the Journal of the American Medical Association.
Quality matters considerably more, in my opinion, to the calories that come in. We all know the food industry's most famous threat: "betcha' can't eat just one!" Of course, it wasn't intended as a threat, but in an age of epidemic obesity, isn't it exactly that?
Foods can, indeed, be processed into virtual irresistibility based on detailed studies of brain function, imaging of the human appetite center in the hypothalamus. And they can be processed into marvelously efficient calorie delivery systems: energy dense, nutrient dilute, low in volume. The modern food industry is highly adept at maximizing the number of calories it takes to feel full—with predictable benefits to those holding company shares, and predictable detriments to the rest of us left holding the bag of chips.
Wholesome, nutritious foods have the opposite effect. Among their many virtues, they minimize the number of calories it takes to feel full, due to many attributes, among them: high volume, high fiber, low-glycemic index/load, nutrient density, energy dilution, flavor simplicity, etc.
So the quality of calories we consume can affect the quantity. This should be welcome news in our ongoing struggles with portion control. If all sources of calories felt the same, the only way to shrink our portions would be to eat less than we now do—presumably less than we want—and to be hungry all the time. Making higher quality food choices offers us means to feel full on fewer calories, and to get thin without feeling hungry.
I'm really happy to read someone who gets it.
Eat 1,500 calories per day while you're burning 2,000, and you're going to lose weight, regardless of what foods those calories come from or what you did to burn them.
Eat 1,500 calories of processed, manufactured crap and you'll be hungry all day. Eat 1,500 calories of real food and you'll be much less hungry. But either way they're the same 1,500.
Burn 2,000 calories by going for long walks, and you burn 2,000 calories. Burn 2,000 calories by doing some High Intensity Interval Training, and you'll burn 2,000 calories, but you'll also get the benefit of burning additional calories tomorrow while your muscles heal and rebuild.
I'd recommend reading this article in full. Then bookmarking it so you can read it again tomorrow, and again later in the month. It's that good.