Are All Calories Created Equal?
How Calories Really Work
The concept of calories probably seems like old hat by now. Anyone who has tried to lose weight is familiar with the delicate dance of balancing calories in versus calories out. But as it turns out, counting calories may not be the most effective method to ensure optimal health, particularly over the long-term. One of the reasons why is that all calories are not created equal.
In the simplest terms, a calorie is a unit of energy. But the concept of calories is actually much more complex than the numbers we associate with every food item. The way our body processes a calorie goes well beyond simply turning it into energy that is used up or stored. For one, the calories that come from nutrient rich foods provide a stable source of fuel without crashes, headaches or cravings. One hundred calories of strawberries or sweet potatoes will take you farther than 100 calories of something like ice cream or white bread.
There are also several factors tied to both the macronutrient and micronutrient content of food that play a role in how calories are handled by your body.
Energy density
Energy density is one of the most obvious ways in which calories differ. Foods with a lower energy density offer significantly more volume with fewer calories, so your stomach feels full more quickly. Low energy density foods include most fruits and veggies like asparagus, spinach, and blueberries—two cups of blueberries has about the same amount of calories as one ounce of chocolate.
Thermic effect
Also known as dietary induced thermogenesis, the thermic effect of food is a measure of how much different foods increase energy expenditure. Put simply: Some foods require more calories to digest than others, thus increasing metabolism. The thermic effect of fat is 2-4%, carbs is 6-8%, and protein is 25-30%. So if you eat 100 calories of lean chicken breast, you’ll burn about 25 of those simply digesting the meat, whereas the same caloric amount of butter would only take about two calories of energy to digest.
Appetite suppression
In addition to increasing metabolism, protein is the most filling macronutrient. When we eat a protein-rich meal, it sets off a series of complex chain reactions that travel between our gut and our brain to signal satiety. Protein also stimulates the production of an appetite-regulating protein called peptide YY (PYY). Thus, the calories from protein provide more bang for your buck—one study found that people who ate more protein automatically took in 440 fewer calories.
The satiety index
The satiety index measures the ability of different foods to reduce feelings of hunger and increase feelings of fullness. Foods that have a lot of fiber, protein, or water tend to be high on the satiety index. Some examples include lentils, eggs, oatmeal, and oranges. Adding healthy fats like salmon, walnuts, avocado, and olive oil to fresh vegetables also increases satiety while helping your body absorb fat-soluble vitamins.
Glycemic load
Glycemic load is a ranking system that measures the amount of carbs in a serving of food. Foods with a low glycemic load have little to no impact on your blood sugar, and the more stable your blood sugar, the less likely you are to have energy crashes and food cravings. Consuming a good portion of your calories from foods with lower glycemic loads, like chickpeas, carrots, and watermelon also helps you crowd out excess sugar, which can cause belly fat, diabetes, and other health issues.
At the end of the day, it’s the quality of your calories that matters—not quantity. When we pack our plates with delicious whole foods, we naturally eat just the amount our bodies need to thrive. Instead of tirelessly tallying every calorie, we can revel in real food and plenty of it!