Calorie Calculator

What are calories?

Definition of a calorie is simple. According to most textbooks on science, is the energy needed for raising one gram water 1-degree Celsius. But how does that relate to the caloriecounts that are displayed everywhere from menus for fast food to snack bar nutrition labels

If we take a look at caloriecounts and calorie counts, we're generally trying to find out how much energy we're pouring into the body. However, a label on a food item is never going to provide that, at a minimum, accurately. There are too many aspects involved, some of that are influenced by the person's physical physiology, and others of which we're still in the process of determining.

It is worth noting that beginning in the year 2020 nuts suddenly appeared to contain around 30 percent fewer calories than they did the year prior. The walnuts and cashews experienced the same decline in their energy densities. The nuts themselves did not change, however, the method used to determine calories did.

This is due to the fact that the FDA and USDA frequently still use a century-old method for measuring calories. It was developed in the 19th century (though exceptions are made if there's more recent research available, for instance, for those who are nuts). In the late 20th century Wilbur Atwater, decided to measure the energy contained in food items by burning the stuff by calculating the amount of energy was in it before feeding the same food to the people and determining how much energy was in their poop and pee. The difference between the energy that was in and the energy that went out, so to speak has become the calorie-calculating numbers we use for macronutrients today nine calories per gram of fat, and four in a gram of carbohydrate and protein.

For the 19th century this was a massive leap in the understanding of energy density of food. However, for the 21st century this doesn't seem to be quite right.

[Related The truth about keeping track of calories[Related: The truth about counting calories

It's true that a calorie of fat in a walnut, for instance, does not appear like the same as the calorie that comes from animal fat. Though it's still unclear why this happens the implication is that our bodies can't digest all food products in the same manner, which means certain calories remain within the food and go to our poop. They haven't any impact on our waistlines in any way. (We should be aware that the calories-in-nuts research was partly funded by various nuts boards, but the interested parties didn't design or conduct the research).

Bioavailability is a concept that has only recently been made a focus of investigation, and therefore we don't have any information about other food items we're ill-informed about quantifying. For instance, we're aware that cooking food is believed to make the nutrients contained in it more easily accessible. We also know that our personal gut microbes help determine how much energy we extract from our food such as by breaking down cell walls inside certain vegetables. The Atwater system doesn't account at any time for cooking food, much less how you cook it, nor does it consider various bioavailability differences between types of food items. It simply focuses on the amount of protein, fat, or carbohydrate are contained in the food.

The new nut studies don't utilize a more advanced technique than Atwater employed. The researchers fed almonds (or cashews or walnuts) to the participants and examined their poop to determine the amount of energy absorption. It's just that the USDA scientists wanted to look at one food item in particular.

As long as we don't find a better method of quantifying the amount of energy contained in each food group, the term calorie, really is just a number we've allocated arbitrarily to food items. It's best not to think about it too much.