Calories: a beginner’s guide
Once upon a time, long before calorie counts were displayed on food menus at restaurants, people were merely focused on finding food rather than worrying about how much energy it contained. Back then, fitness wasn’t about hitting your daily step goal but outrunning predators or hunting dinner. The idea of measuring the energy in whatever you managed to catch would’ve been absurd. But as humanity evolved, so did our curiosity about what food does for us beyond just leaving us satisfied.
Enter the calorie. A concept that first appeared in 1824 when physicist Nicolas Clément introduced the term in the journal Le Producteur. Later, in the late 1800s, German physiologist Carl von Voit brought food science to life by building one of the first labs to measure energy in food. Today, calories are part of our everyday language, plastered on nutrition labels and fueling everything from workouts to debates over fad diets. But what exactly are they? Let’s dig in.
What are calories?
A calorie is a unit of measurement for energy — the kind your body needs to do everything from blinking to running a marathon (or just running late). Scientifically, one calorie is the amount of heat required to raise the temperature of 1 gram of water by 1°C. However, the “Calories” you see on food labels are actually kilocalories, which means they’re 1,000 times larger than the calories scientists use in labs. So when your granola bar with 300 calories, that means it has 300,000 tiny energy units powering you up — which, in perspective, makes it look mighty stronger.
In simpler terms, calories are the fuel that keeps your body operating. Every bite of food you eat gets broken down and converted into energy. This supports your daily activities, whether lifting weights, lifting groceries, or just lifting your phone. Without them, your body wouldn’t have the power to function. So, think of them as tiny batteries powering your body: too few and you won’t be able to function, too many and you might overload.
Why they matter
Calories are essential because they determine whether your body uses energy immediately or stores it for later. If you eat more calories than your body burns, the excess is stored as fat. If you burn more than you consume, your body taps into fat reserves, leading to weight loss. Without the right balance, you might end up gaining weight (if you’re consuming too much) or feeling fatigued and losing muscle (if you’re consuming too little).
How many calories do I need?
The number of calories you need depends on factors like age, gender, weight, height, and activity level. Your Basal Metabolic Rate (BMR) represents the calories your body needs to maintain basic functions. Then, there’s TDEE (Total Daily Energy Expenditure), which is the total number of calories you burn in a day, including both your BMR and the calories burned through physical activity.
Once you understand these numbers, it’s simple math: to maintain your weight, eat around the calories your TDEE suggests. For weight loss, eat fewer calories than your TDEE (calorie deficit). For muscle gain, eat more (calorie surplus, especially with a focus on protein). Knowing your numbers allows you to tailor your diet to your fitness goals and helps you eat healthier overall.
