As a registered dietitian, the thought of anyone counting calories, aka the energy you get from what you eat and drink, causes me to sigh audibly. Counting calories is a time-consuming, soul-sucking practice that’s actually a lesson in futility, as far as I’m concerned.
Yet people continue to do it. They pull out their calorie-tracking apps and plug in whatever foods they’ve eaten, feeling guilty when they go over their “recommended” calorie amounts, then running to the gym to try to undo it all. And I can’t blame them: The idea that monitoring all your calories is key for weight loss is a popular one.
While I do think there’s value in recording the foods you’ve eaten to understand what you’re consuming and offer accountability, and while I do think it’s important to know relative calories (e.g., cake: high, broccoli: low), it’s a colossal waste of time to drill it down to every single calorie that passes your lips.
1. You likely have no idea how many calories you actually need.
In order to accurately count calories for weight loss, you’d need to know your basal metabolic rate, or how many calories your body burns each day simply to stay alive and keep all your systems running. And unless you’ve done indirect calorimetry, which I can almost guarantee you haven’t—it involves lying with a mask on, hooked up to a very expensive piece of machinery for a prolonged period of time to measure your oxygen intake and carbon dioxide expulsion—you really are playing with arbitrary numbers. Although it’s the “gold standard” of figuring out how many calories you use per day, like anything else, indirect calorimetry can have flaws.
Yes, you can approximate the number of calories you use in a day via equations and apps, but that’s all you get: an approximation. If even the “gold standard” machine can be wrong, then why let some app or equation determine how much you should be eating?
2. You don’t know how many calories your body is absorbing from food.
Let’s say that by some miracle, you know exactly how many calories you need to eat per day for weight loss. That’s great, but you’re not out of the woods, thanks to the question of absorption.
We used to think that since 3,500 calories equal a pound, every time you eat 3,500 extra calories beyond what your body needs, you end up gaining that weight. Now we know better: Not all calories are equal like we thought.
Everything from how your food is processed to how much fiber it contains determines how many calories you’re absorbing from it. Even the bacteria in your gut may play a part in how you digest food and how many calories you derive from it.
For example, you’ll absorb more calories from cooked meat versus raw, and peanut butter versus whole peanuts. Due to size differences, one sweet potato varies in calories from another before you even take it off the shelf at the store. Calories absorbed is a complex business that’s light years beyond any calorie-counting app on the market.
3. Calorie counts on packages aren’t necessarily accurate.
But wait! Even if you know how many calories you need and how many you’re absorbing, you’re not done! In fact, the Food and Drug Administration allows up to 20 percent margin of error in the numbers on those nutrition labels you likely rely on to count many of your calories. Meaning, that 250-calorie snack you’re eating might actually have 200 calories—or 300.