The Calorie Balance Equation – Part 1

The Calorie Balance Equation – Part 1
by Erik Castiglione

Depending on which source you go to, and which echo chambers you subscribe to via social media, you’re bound to get conflicting reports about nutrition. In the blue corner, we have the “calories in, calories out” folks. In the red corner, we have the “hormones rule all, calories don’t matter” crowd. And then in the stands, you have the “food quality, not quantity is what matters” contingent, as well as the “diet doesn’t matter as long as I exercise” people. So, who is correct? Well, each of these beliefs has its respective place, and I’m going to reconcile them for you in this two-part series. Enjoy!

According to the First Law of Thermodynamics, energy can neither be created nor destroyed; it can only be changed from one form to another. Did you know that a calorie is a unit of energy? It’s true! A calorie is defined as “the amount of energy required to raise 1 gram of water by 1 °C.” Also relevant is the fact that your body stores as glycogen in your muscles and liver for imminent use, and as adipose tissue (fat) for long-term use. Both types of energy stores can lead to increased weight. Glycogen stores also store water, so when you have a high carb meal and feel “bloated” the next day, that’s why. I don’t think I need to explain how stored body fat leads to increased weight.

When it comes to nutrition, these facts yield the Calorie Balance equation:

Changes in body stores = Calories InCalories Out

This equation means YOU MUST EXPEND MORE CALORIES THAN YOU TAKE IN to lose weight. Sorry folks, this is physics, and cannot be ignored or worked around. As much as I would like to work around the law of gravity and gain the power of flight, I’m not Superman (I’m getting close, though. I’m also the humblest person in the world).

Now, before you freak out and start starving yourselves and exercising like crazy to lose weight, hormones, food quality, and exercise all have their place in this equation. The reality is this is only a top-level equation. Both terms, Calories In and Calories Out, are made up of other variables:

Calories In = Calories Ingested – Calories Not Absorbed.

Calories Out = Basal Metabolic Rate + Thermic Effect of Food + Physical Activity + Non-Exercise Activity Thermogenesis

The Calorie Balance Equation - Part 1
Courtesy of Precision Nutrition

There’s A LOT to tackle here, which is why this is a two-part series. In this part, we’re going to stick with the Calories In piece.

Part of the reason that most people struggle to lose weight, is that they don’t accurately account for their Calories Ingested. It’s VERY easy to underestimate them. Here’s a quick example: Jane Doe wants to lose 20 lbs and learns that she needs 8oz of chicken 3 times per day to get her desired amount of protein (4oz = 21g protein à 24oz = 126g protein). What Jane fails to account for is that the measurements she’s using are based on RAW weight, NOT cooked weight. Since 4 oz raw yields roughly 3 oz cooked, if Jane is eating 24 oz of cooked chicken in a day, that’s the equivalent of 32 oz of raw chicken. She’s not getting 126g of protein; she’s up at 168g. And since 1g of protein is equal to 4 calories, she’s getting an extra 168 calories per day just in chicken.

The above example is for someone who is methodically tracking their intake. Many of us who are a little more casual about tracking also routinely eat “one-offs” that we don’t track. This could be the dressing on your salad, sauce on your meal, cream/sugar in your coffee, or that munchkin/ half donut that you had in the break room. Over time, it all adds up.

To complicate the Calories In piece further, it’s impossible to account for how many of those calories we absorb. We don’t absorb all the calories we ingest. This, too, is dependent on a couple factors. First, it depends on the bacteria in your gut. Everyone is different, so unless you get a gut culture performed (unless you have serious auto-immune issues, I recommend you skip this), you won’t know the make-up of your gut. Second, we absorb more calories from more processed foods. We absorb a higher percentage of the calories from the hyper palatable junk food we enjoy as treats than we do from fresh vegetables. Additionally, grinding, boiling, cooking, etc. are also ways we process food. We absorb more of the calories in a serving of peanut butter than we do from an equivalent serving of peanuts.

The Calorie Balance Equation - Part 1
Courtesy of Precision Nutrition

So, since it’s so difficult to measure our Calories In, do we just toss our hands up in the air and say, “screw it?” NO! We focus on eating the best foods we can, while paying attention to quantities. In other words, food quality AND quantity BOTH factor into the Calories In piece of the Calorie Balance equation. If you have one takeaway from this post, that should be it. Next week, we’ll look at the more complicated Calories Out piece. See you in the gym.


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