What is a calorie?
Now, before you open up a new tab on your browser and start typing into Google: “what is a calorie?”, just off the top of your head, can you explain to me what a calorie is?
Technically, a calorie is a unit that is used to measure energy. A Calorie (kcal) is the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius. In the past, to determine how much nutritional calories a particular food had, it was placed in bomb calorimeter— an apparatus with a sealed container surrounded by water— and then ignited and completely burned until almost nothing was left. The resulting rise in water temperature from the incineration was measured and thus determined how much “energy” the food had. This how we know that one gram of carbohydrates or protein contains 4 calories and one gram of fat contains 9.
But doesn’t this make you wonder what the connection is between the amount of heat released when a food is literally burned to how a human body digests it and uses it for energy? Well, it’s a complicated question. The problem with this outdated calorie-measuring system is that it doesn’t take into account the vast amount of science and research we’ve accumulated regarding human metabolism. Incinerating foods to measure energy output was a good start, but in the 21st century, this is an unbelievably archaic and outdated way to accurately measure calories. Incineration, of course, does not equal human digestion. Would eating a fireplace log give you as much energy as burning it in a fireplace? No way.
The main reason why our body cannot derive as much energy from a piece of bark compared to, say, a piece of fruit, is because our bodies are not capable of breaking it down for energy. And if we cannot break it down properly, it passes through our body and never enters our bloodstream. So it’s not so much what you put in your mouth that matters; it’s what makes it to your bloodstream.
Different calories = different outcomes
Let’s say three females of the same race, age, and body composition each consume 2,000 calories daily for 30 days. Subject 1 consumes nothing but table sugar, subject 2 consumes nothing but lean chicken breast, and subject 3 consumes nothing but mayonnaise (2,000 calories is just 19.4 tablespoons, if you’d care to indulge).
Will the body composition outcomes be the same?
Of course not. The hormonal responses to carbohydrates (CHO), protein, and fat are different. There is no shortage of clinical studies that prove that calories from beef do not equal calories from vodka.
Protein, for example, provokes a greater thermic effect of food than either carbohydrate or fat. This means that while your body is digesting protein, a higher percentage of protein calories are “lost” as heat vs. carbohydrates or fat. This has led some scientists to suggest that the 4 calories per gram assumed for protein should be downgraded 20% to 3.2 calories per gram. In addition, protein increases satiety (the feeling of fullness) to a greater extent than fat or protein. So if you’re not feeling hungry, you’re less likely to snack on unhealthy treats and therefore facilitate a lower overall caloric intake.
However, I’m not advocating for an Atkins-style diet. Most people assume that an Atkins diet means eat-all-the-meat-and-fat-I-want while avoiding pasta and bread. This is truly unhealthy. Sure, you might lose a few pounds, but that high protein and fat diet will have other consequences down the road, like high cholesterol and arteriosclerosis.
The key to losing weight is not losing weight, its keeping it off
The hardest part of any diet is compliance. So if you make unsustainable ultimatums in your diet like “1200 calories per day” or “no ice cream,” you’re just setting yourself up for failure. Moderation and portion control is key, not so much what fad diet you decide to choose. Making small changes in your diet is the best way to make long lasting changes.
For more information, check out Good Calories, Bad Calories & The 4-Hour Body: An Uncommon Guide to Rapid Fat-Loss, Incredible Sex, and Becoming Superhuman.