Weight and Math: When the Numbers Don’t Add Up (And Whether You Should Add Them Up at All)

Calories in versus calories out. Who’s heard that phrase before? If you’ve attempted weight loss in the past, it’s likely you have.

This phrase – calories in versus calories out – is really about math. If the person first determines how many calories their body burns each day, then consumes fewer calories than that number, they’ll lose weight, right?

Hypothetically, yes.

But not always.

It’s complicated.

Here are some of the problems that come up with this mindset towards weight loss.

People aren’t very good at counting calories.

On one side of the above equation, you have “calories in,” referring to the number of calories you eat from food each day. While nutrition labels and phone apps may lead us to think otherwise, the reality is that nearly everything about calorie counting is estimated – most often underestimated.

We also aren’t very good at knowing how much energy our bodies burn each day.

In other words, we’re dealing with an equation in which the only two variables in play are unreliable. Think your treadmill is accurate when it tells you how many calories you’ve burned? Think again. The amount of energy your body uses each day depends on your age, gender, body size and composition, as well as the amount and type of physical activity you engage in. Certain formulas (like the Harris-Benedict or Mifflin St. Jeor) will get you in the ballpark, but much energy and frustration is wasted by people trying to calculate their exact energy expenditure every day.

Calories in versus calories out is missing a few variables; actually, a lot of variables.

Here are just a few examples of “calories in versus calories out” not giving the full picture when it comes to weight loss:

  • The microbiome (bacteria) in your gut plays a huge role in affecting how many calories your body absorbs. We inherit a baseline population of gut bacteria at birth but can affect it throughout life in a number of ways. A high-fiber, plant-rich diet tends to produce more diverse bacterial populations with lower body weights on average.

  • Certain medications can either promote weight loss or weight gain.

  • Chronically high levels of stress promote the release of cortisol, which then increases fat storage in the body.

  • Poor sleep patterns increase the likelihood of weight gain in a number of ways. A shift in hormones in sleep-deprived individuals leaves them hungrier and more likely to store excess calories as body fat. You should shoot for a minimum of seven hours nightly, but some people need more.

  • As our body weight changes, so do our calorie needs. As I’ve pointed out in this space before, the “3500 calorie rule of weight loss” is often misleading.

Although an awareness of calorie density in various foods can be useful in managing weight, calories are far from the only variable in play. Build a lifestyle that addresses more than just how many calories you eat. The types of food you eat, how you manage stress, how you move your body, and your sleep pattern all play vital roles in the body’s ability to manage weight. For most people, all that math is more trouble than it’s worth.

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