Although we tend to associate calories with food the actual definition of a calorie is the amount of heat required to raise the temperature of 1 gram of water by 1 degree Celsius.
The obvious question is why would we measure the potential energy in food?
Scientists measure the energy content of food by combusting the food in a machine known as a bomb calorimeter. When using a bomb calorimeter, food is placed in the device and electrical energy is used to ignite the food. As the food burns it heats up the surrounding air, which expands and escapes through a copper tube that leads the air out of the device. As the air escapes through the tube it also heats up the water outside the tube. The temperature of the water allows observers to calculate calorie content of food. So being that you are measuring food energy in this way it only makes sense to report food energy in terms of heat units. This is how the following caloric contents were derived:
Fat contains 9 calories/gram
Carbohydrate contains 4 calories/gram
Protein contains 4 calories/gram
Alcohol contains 7 calories/gram
Calorie counting has its place, although, in my opinion, this is rare. Focusing on these numbers can be a good indicator under certain circumstances, BUT here are some of the reasons counting calories will never be accurate, even if your body does use them as a machine burns fuel – which, trust me, it does NOT.
- Dates on foods can be out of date and inaccurate, and this throws energy and nutrient calculation on the label or in the nutrient databases off.
- Different batches of both natural and processed foods vary in their exact contents. Using a single test at a single point in to describe all batches into the future will be full of obvious errors.
- Produce grown in nutrient rich soil is different from produce grown in nutrient depleted soil.
- Ripeness at the time of harvest can have an effect on nutrition and caloric content as some produce is picked out of season, again throwing off these values.
- What an animal ate can have an effect on the nutrients in the actual food so think about what we get from animals. This is going to affect nutrient counts in milk, meat and eggs.
- The length of storage can also have an effect on nutrient count. If a food is harvested this morning it will have significantly different nutrient content from something you buy at a grocery store that was harvested 3 weeks ago in another country.
- Preparation method and cooking time can change nutrition and caloric values. Raw produce is much different than eating cooked produce. The amount of cooking and processing affects the amount of energy and the nutrients we are able to assimilate and absorb from that food. Cooking the food USUALLY makes more energy available to us.
The above factors are what can cause an approximate 20% error when you consider calories. Some will be off by showing more calories than what is accurate and some will show less. If it really was all about the calories, how would we ever get an accurate count of our caloric intake? And just a little too much here and there (even just a bite, or a few percentage points) would, in this theory of numbers, cause continuous weight gain.
Another thing that the people will talk about regarding why counting calories is not a good way to manage your diet is that your energy expenditure and workouts each day are going to vary in their nature and intensity and thus, in the numbers game, will influence the amount of calories you are burning each day. How can you ever determine this with 100% accuracy?!?! While this is true, a calorie surplus will most likely lead to some extra energy in your next few workouts, while a calorie deficit will lead to less of an intense workout. Are you starting to see how our body balances this stuff out?
It’s time to let go of the numbers, the misconception of the calories in vs. calories out theory. The body is more like a chemical lab than a machine and food is information along with energy. It is this information which directs the body in what to do with what you have consumed. Focus on eating real food. Give your body the tools it needs to create sustainable balance and ease. This is how we find food freedom!!