What are calories?

What are calories?

Definition of a calorie appears to be easy: according to most textbooks on science, that's how much energy required to raise one gram water to just one degree Celsius. But how does that relate and relate to caloriecounts that are displayed all over everything from menus for fast food to snack bar nutrition labels

When we consider caloriecounts in the context of calorie count, we're generally looking to know how much energy we're putting to our bodies. But a nutrition label will never be able to provide that, at a minimum, precisely. There are too many aspects at play, many of that are influenced by the individual's physical condition, and others of which we're still working out.

Look at this: From the year 2020 nuts suddenly seemed to have around 30 percent less calories than they did the year prior. Both walnuts and cashews saw the same decline in energy density. They didn't alter themselves, naturally, but the method used to calculate calories changed.

This is due to the fact that the FDA and USDA generally still employ an old method of measuring calories. originating in the late 19th century (though exceptions can be made when there's more current research available, like for peanuts). In the latter part of the nineteenth century Wilbur Atwater decided to assess the amount of energy in foods through burning the ingredients, quantifying how much energy was inside it, then feeding the same food items to people and determining how much energy was in their poop and pee. The difference in energy that was in and the energy that went out, or energy has become the calorie-calculating numbers that we currently use for macronutrients 9 calories in a gram fat, and four in grams of carbohydrate and protein.

For the 19th century, this was a massive leap forward in our understanding of the energy density of food. But for the 21st, it's not quite as clear.

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An calorie of fat found in nuts, as an example, isn't likely like the same thing as the calorie of animal fat. It's still not clear what causes this but it is believed that our bodies aren't able to break down all foods equally, which means some calories remain within the food, and then go into our poopand never have impacted our waistlines at all. (We need to note that the research into the calories found in nuts was partly funded by various Nut boards, even though the interested parties didn't design or perform the studies themselves).

Bioavailability is just recently become a subject of study, and there's not much information yet on what other types of foods we may be improperly quantifying. For instance, we know that cooking food can seem to make the nutrients inside it more accessible. We also know that our own gut microbes help determine how much energy we extract from our food for example, by breaking down cell walls inside certain vegetables. The Atwater system does not account at any point for cooking food regardless of how you cook it, neither does it take into account various bioavailability differences between types of foods. It's just based on the amount of protein, fat or carbohydrate are in the food.

The new nut studies don't even use a much more advanced method than Atwater utilized. The basic idea is that the researchers gave almonds (or cashews, walnuts or even cashews) to the participants and they measured their poop for the amount of energy taken in. The difference is that USDA scientists wanted to study one specific food item in particular.

until we can find a better method of quantifying the amount of energy within a specific food group that is an calorie, really, is a number we've assigned to food. Try not to take it too seriously.