Not All Calories Are Equal
From a young age we are taught that the key to maintaining weight is to burn off as many calories as we ingest. We also have learned that weight loss occurs when we consume less calories than we expend, and that we gain weight when we eat more than we burn off. However, research over the past decade has shown us that this formula may not be quite as simple as it seems.
A calorie is actually a measurement of heat energy. Specifically, it is the amount of energy that is needed to raise the temperature of one kilogram of water by one degree Celsius. This heat energy is what gives our body fuel. Our calories come from the protein, fat and carbohydrates that we eat. Protein and carbohydrates have 4 kcal/g, fat has 9 kcal/g, and alcohol has 7 kcal/g.
Current research shows us that the source of our calories is extremely important, and that different food groups affect our weight status differently. It is a myth that a calorie is just a calorie. While all calories do have the same amount of energy – 4184 Joules of energy – our body reacts to the sources of calories differently. This is because we digest and absorb various types of food differently. Those foods go through diverse biochemical pathways and affect hormones in the body, which may also affect satiety and hunger.
As stated above, different foods are digested and go through different metabolic pathways, some of which are more efficient than others. Protein requires a lot more energy to metabolize than fats or carbohydrates. When protein is ingested, it requires more energy to digest and absorb, which uses more energy. Therefore, the calories ingested from protein are less fattening than carbohydrate or fat calories.
Another benefit to protein is that it increases satiety more than the other macronutrients. Appetite is reduced and less food and calories are consumed, which may lead to weight loss. This just demonstrates that the type of food that you eat is extremely important, and that all calories are NOT the same.
Further, people who eat whole foods rather than processed foods tend to eat less and have less issues with obesity. Whole foods require more energy to break down and digest than processed foods. This is because many processed foods contain refined carbohydrates, which are low in fiber, low in nutrients, and usually have a high glycemic index. Foods with a high glycemic index are digested quickly and rapidly spike blood sugar levels. This causes food cravings and increased hunger and food intake.
Additionally, foods high in fiber are less likely to cause weight gain. This is because more energy is needed to breakdown the food, and much of the fiber is not absorbed into the body but rather is excreted as waste. Therefore, the body is not necessarily getting the amount of calories listed on the label.
The take home message is not to worry about counting your calories to lose weight. The food choices that you make are much more important for both your health and for your weight. Different food sources affect energy expenditure, hormones, and hunger, which all affect satiety and weight gain. Think about what you are eating rather than how many calories you are eating and look at your food a little differently. If you change your perspective, you will ultimately reach your goals and get healthy!
By Denise Groothuis