It turns out that King Calorie, ruler of diets and dieters everywhere, might actually be a fraud. And what we all thought was solid scientific data, a case of the emperor's new clothes.
The unit of measure we called a calorie is the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius. Way back in the 19th century, an American chemist named Wilbur Atwater measured the available energy in all sorts of foods by calculating an average of fats, carbohydrates, and proteins. We still use his averages today.
And that's where things start to get a little iffy.
Raw vegetables and meats are harder for the human body to digest compared with cooked veggies and meats, and therefore the body absorbs fewer calories from raw foods than from cooked ones. Soft, sweet fruits have evolved to be easier to digest so that the animals that eat them will help dispurse the plant's seeds; the seeds, on the other hand, are hard to digest, in the hopes that they will survive the passage through the digestive tract and germinate. Starting to see a pattern here?
The study found that 170 calories of raw almonds will only yield a caloric intake of 129 calories. On the other hand, it also found that the same amount of sugary cereal will often have higher caloric yield than what's listed on the label. And if you think you're doing yourself a weight loss favor by eating more fiber? You're not. The calories in fiber have never been accounted for.
In the study, one group of mice was fed raw sweet potatoes, while a second group was fed cooked sweet potatoes. The group eating the raw foods lost weight, while the group eating the exact same quantity of cooked food, gained weight.
In addition, scientists have discovered that the amount and types of bacteria in any given individual's gut can also affect how many calories are absorbed by the body. Bacteria that help break down foods keep some of the calories for themselves, but if a person has very efficient gut bacteria, or an unusual abundance of bacteria, he might receive more of the calories eaten than a person who has less efficient bacteria in her gut.
So in effect, two people could sit down to eat exactly the same meal, prepared in exactly the same way, and actually absorb two very different amounts of calories.
The upshot? People interested in weight loss should stop obsessing about calorie counts and instead focus on eating raw, whole foods instead.