Is a Calorie Really Just a Calorie?
Calories in, calories out. That's how we lose weight, right? Maybe not.
Let's dig in to what a calorie actually is. Simply put? Energy.
Food is energy for the body. Digestive enzymes in the mouth, stomach, and intestines break up complex food molecules into simpler ones, such as sugars and amino acids that travel through the bloodstream to all our tissues. Our cells use the energy stored in the chemical bonds of these simpler molecules to perform the functions we need to live.
Mark Sisson explains: "We calculate the available energy in all foods with a unit known as the food calorie, or kilocalorie—the amount of energy required to heat one kilogram of water by one degree Celsius." Fats provide approximately 9 calories per gram, whereas carbohydrates and proteins deliver just 4, which might be one reason that people avoided fat for so long in a failed attempt to lose weight.
Now, I know calories are important! But checking the labels for calorie count is not helpful. These are just an estimate, pulled by a computer database. So when you stare at the 108 calories on a packaged food, remember it's not exact. PLUS, food manufacturers can underreport calories by 20% and pass inspection by the FDA!!
It doesn't matter anyway. Here's why:
Science has proven that calories that spike your blood sugar and insulin promote weight gain, while calories that do NOT spike blood sugar (fats, vegetables and some protein) actually speed UP metabolism. 500 calories of Coke does NOT equal 500 calories of almonds! Soda is also nutrient devoid, so almonds are clearly a better choice for a whole handful of other reasons.
Dr. Hyman explains, "The higher the fat, the lower the carbs, the greater the weight loss. It's not about the calories themselves, but how those calories affect your metabolism. Fat speeds up your metabolism and burns body fat. Carbs slow it down and promote weight gain." WOW!
Calories out is also another confusing topic. We think if we cut calories by eating less or burn calories while exercising, we should lose weight. But there are also other ways we burn calroies! There is something called Resting Energy Expenditure — the energy used to handle basic functions and maintenance. We also need to consider Thermic Effect of Food — the energy used to digest food and process nutrients.
Did you know? Whole foods take more energy to process and digest than processed foods. We can actually burn more calories just by digesting healthier food options. No-brainer!
One last point to remember: Weight loss and fat loss are NOT the same thing!
We don't truly want to lose weight. We want to lose body fat and retain, or gain, muscle. 150lbs of fat looks and feels a whole lot different than 150lbs of muscle. Studies indicate that the macronutrient composition can differentially affect whether the weight lost is actually fat. It’s not just about total calories.
Sources and Additional Reading:
"Food: What The Heck Should I Eat", Dr. Mark Hyman, 2017
Institute for Integrative Nutrition, 2018