Updated: Jul 10, 2018
The word is everywhere. You hear it on TV. You read it in fitness magazines. It's on the back of all food labels. You vaguely know you're supposed to avoid them like the plague if you're trying to lose a few pounds (ps. not an effective long-term strategy)... but what exactly is a Calorie?
To put it very simply, a calorie is a way of measuring energy. It's actually a unit of heat and we use heat to help us determine how much energy food contains. The more calories something has, the more energy it contains. If we want to dig really deep in understanding what a calorie is (bare with us for just one second as we get all technical)... it's the amount of energy it takes to raise the temperature of 1 gram of water by 1 degree Celsius.
Notice I've spelt calories with a lower case "c". If we capitalize the "c", it refers to the amount of energy it takes to raise the temperature of 1 kilogram of water by 1 degree Celsius (this is spelled "Calorie" and sometimes said "Kilocalorie"). This is the term we are most often using.
But let's get a little more practical.
How does this relate to you?
Everything we do (from thinking to moving) requires energy. When we consume food, we are consuming the food's potential energy. For example, if a food contains 1 Calorie (for simplicity's sake), it can provide us with the same amount of energy that would be required to raise a kilogram of water by 1 degree C.
I say food's potential energy because although the food contains that amount of energy, whether our body will extract and use that energy will depend on several factors, including our digestive health and the quality of the food. I will loop around and come back to this later, but we are typically able to extract about 91% of the energy contained within the food we eat (that's pretty good!).
On a very generalized scale, an average 70 kg (154 lb.) person might consume about 2000 Calories a day to sustain regular daily activities. This amount of Calories fuels several factors including our Basal Metabolic Rate or Resting Metabolic Rate (which represents the minimal amount of energy required to sustain vital functions of the body, usually about 70% of our energy expenditure), the Thermic Effect of Feeding (the energy we need to digest the food we eat, which is about 10% of our total expenditure), and physical activity which includes both exercise and non-exercise activities (like getting dressed, the action of cooking our food, walking from one place to another, etc.).
We need to keep in mind that this number can vary greatly depending on your age, activity levels, body size, lifestyle, and even things like your hormones.
How are you supposed to know how many calories to eat?
Here's the thing... You shouldn't have to count.
A good diet maintains energy balance. This means that the amount of calories you eat matches the amount of calories your body needs to do what it needs to do in a day. Excessively eating less calories than the amount you are burning puts you in a calorie-deficit, which often results in short-term weight loss, but has much greater and longer term impacts on your overall metabolic rate.
I know that in a culture of Calorie-counting, this concept is hard to grasp, but we weren't born with calculators in hand to help us add up the caloric content of the food we consume. We were born with these amazing bodies that have internal mechanisms that do all of that for us. We have two systems in particular that are especially helpful in regulating our energy balance.
These two systems are:
1) The Endocrine System
2) The Nervous System (specifically our Enteric Nervous System, which is our "second brain" located in our gut)
We won't dig too deeply into these systems today, but what is important to understand is that our bodies are equipped with systems that (when working properly) regulate our appetite and energy expenditure (how many calories we eat and how many calories we burn). When we eat a diet of whole, natural foods, these systems work well. When we eat highly processed, synthetic, food-like substances (sadly, this type of "food" bombards our markets), we run into some problems.
As promised, I'll loop back to the concept about digestive quality and food quality.
Digestive & Food Quality.
The microbiome of your gut (the types and balance of bacteria), permeability of the stomach lining, inflammation and irritation of the tissues, compromised stomach acid, elevated cortisol (stress hormone)... All of these factors can compromise your body's ability to digest and process the food you eat. What you eat also influences these factors, so it's important to consider the quality of the food you put into your body. For example, partially hydrogenated vegetables oils (commonly found in baked goods, deep fried foods, packaged snacks, etc.) impair our endothelial function and attenuates nitric oxide production (disabling our blood vessels from dilating, which restricts blood flow and nutrient delivery while increasing our risk of cardiovascular disease and hypertension).
As you can see, there are many factors that can contribute to the nutritional quality of a food that often go unaccounted for when we look at food strictly in terms of Calories.
We need to take a look at the body's
- Hormonal Response (what chemicals are released in the body as a reaction to these foods?)
- Enzymatic and Metabolic Pathways engaged (what systems are engaged to process these foods?)
- Satiety Response (how full do you feel for how long?)
These factors alongside other factors send chemical information that will be received by our body determining not only how we will extract energy and nutrients from this food, but also the long-term impact on our metabolism, which can be defined as the sum of all of the chemical reactions that help us transfer energy from food into energy our body can use.
In this light, we can see that food is not only a source of Calories, but it is a source of information turning on and off certain systems in our body that can either help or hinder us.
I know trying to eat "healthy" is overwhelming as it is- especially during this time in history where what is considered "healthy" seems to change every other day.
Although using calories to tailor your diet can be very useful in certain circumstances (i.e. understanding your eating habits, etc.), always counting your calories might not be a sustainable, effective, nor enjoyable way for you to live a healthier more vibrant lifestyle. In short, I believe addressing the health of your system first should pave to the way to eating more intuitively and enjoyably for your own body.
Stay tuned to our blog for more information and tidbits on everything food and physiology!