What are calories?

What are calories?

Definition of the term calorie isn't hard: according to the majority of science textbooks it's the amount of energy required for raising one gram water by an inch Celsius. But how does that relate in relation to caloriecounts we see on everything from fast food menus to the nutrition labels of snack bars

When we consider caloriecounts when we look at caloriecounts, we're generally looking to know how much energy we're pouring into our bodies. But a nutrition label cannot be able to tell you that, at least not completely. There are a myriad of factors that are at play, many of which depend on the individual's physical condition, and others we're just finding out.

Think about this: In 2020, the almonds suddenly were able to provide around 30 percent less calories than they did the year before. Cashews and walnuts went through the same drop in energy density. Nuts themselves didn't change, obviously, but the method used to determine calories changed.

That's because it's because the FDA and USDA generally still employ an outdated method for measuring calories. originating in the late 19th century (though some exceptions are made when there's more current research available, for instance, for some nuts). In the 18th century Wilbur Atwater, decided to gauge the amount of energy in foods by burning them by calculating the amount of energy it contained and then feeding the same food items to people and analyzing how much energy was contained in their poop and pee. The difference in energy in and energy out, so to speak is what became the calorie-calculating number that we currently use for macronutrients nine calories per gram of fat, and four calories in a gram of carbohydrate and protein.

For the 19th century, this was a major leap forward in the understanding of energy density in food. But for the 21st, it doesn't quite add up.

[Related The truth about the counting of calories[Related: The truth about counting calories

The calorie of fat in a nut, for instance, doesn't seem to be the same thing as a calorie from animal fat. Although it's not clear why this happens however, it appears that our bodies can't break down all foods equally, which means some calories remain in the food and go to our poop. However, they haven't had any effect on our waistlines. (We are reminded that the research into the calories found in nuts was partly funded by various board members, although these parties did not design or conduct the research).

Bioavailability is a concept that has been a relatively recent topic of investigation, and therefore we don't have any information on what other types of foods we may be improperly measuring. We've discovered, for instance cooking food tends to make the nutrients contained in it more accessible. We also know that our personal microbes living in our intestines help determine how much energy we extract from our food for example, by breaking down cell walls in certain vegetables. The Atwater system doesn't take into account all for the cooking process, and even less, the method of cooking it, and it doesn't take into account differing bioavailability of different kinds of food items. It's all about the amount of protein, fat or carbohydrate in the food.

The new studies on nuts don't employ a more sophisticated approach than Atwater employed. The researchers fed almonds (or cashews or walnuts) to the participants and the study measured their poop in order to determine how much energy was absorbed. The difference is that USDA scientists wanted to look at one food item in particular.

until we can find a better method of calculating the amount of energy in any one food group in the near future, the term calorie is, in reality is a number that we've assigned somewhat arbitrarily to food. Try not to take it too seriously.