The Truth Behind Calories

This is my definition of a calorie.

Unfortunately, calories are really a unit of energy. In nutrition, they refer to energy consumption through eating and drinking, as well as energy usage through physical activity. But they also refer to anything that contains energy, such as coal.

Humans need calories to survive, however how many calories you need depends on a number of factors, including your general health, physical activity demands, sex, weight, height, and shape. The average daily consumption for a man should be somewhere around 2,700, and 2,200 for women. But again, this number is different for everybody. Watch a video on what 200 calories looks like.

Today, every packaged food has a nutrition label listing the number of calories in a serving of the product. But since everybody has a different and complex digestion system most of these calories are incorrect because they are based on a system of averages that ignore how an individual responds to the food.

A recent study reveals that current calorie counts do not consider that how many calories an individual extracts from food, it depends on which species they eat, how the food is prepared, the bacteria present in their gut, and how much energy is used to digest different foods.

For example, vegetables vary greatly in their digestibility. Humans are able to heat the stems, leaves, and roots of hundreds of different plants. Within a single vegetable there are many ways to change the amount of calories it has. Older plants tend to have studier cell walls leading them to have fewer calories than weak or degraded plant material. Cooking quickly ruptures cells in certain plants like spinach, but water chestnuts are much more resistant to the effects of cooking.

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"When cell walls hold strong, foods hoard their precious calories and pass through our body intact (think corn)."

Food labels also do not always consider the structure of different foods. It takes as much as five times more energy to digest proteins than fats because our enzymes must unravel the tightly wound strings of amino acids in proteins. Other foods, such as honey, are processed so quickly that they break down right in our stomach and pass into the bloodstream.

Lastly, even if two people ate the same amount of food, prepared the same way, they would extract a different amount of calories. This is because there are different types and levels of bacteria in everyone's stomach and these bacteria are responsible for the rate at which food is processed in the digestion system. Many modern diets include food that is easy to digest and process. This means that the population of gut microbes that evolve to digest the more fibrous matter might be diminishing.

Calorie counts on nutrition labels will never be perfect but scientists are working on making them more accurate. But it all comes down to what to buy at the grocery store and living a healthy lifestyle. According to the article, "Merely counting calories based on food labels is an overly simplistic approach to eating a healthy diet -- one that does not necessarily improve our health, even if it helps us lose weight. Instead we should think more carefully about the energy we get from our food in the context of human biology. Processed foods are so easily digested in the stomach and intestines that they give us a lot of energy for very little work. In contrast, veggies, nuts and whole grains make us sweat for our calories, generally offer far more vitamins and nutrients than processed items, and keep our gut bacteria happy. So it would be logical for people who want to eat healthier and cut calories to favor whole and raw foods over highly processed foods."