A calorie is a measure of energy used to perform bodily functions like breathing, thinking, digesting food, moving, etc. Obesity is caused by consuming excess calories and weight loss is achieved through a calorie deficit. To lose weight, more energy must be expended than consumed. The more movement, the more calories burned. (Hence the importance of exercise.)
Does this mean, for the purposes of weight loss, every calorie is the same regardless of what food it comes from? Are all calories created equal no matter their source?
The answer is no. Different foods affect the body in different ways before being turned into energyi. Some calories are more valuable than others. For example one apple has roughly the same number of calories as three squares of milk chocolate, but there’s a huge difference in the way they affect appetite, energy level, and long-term health.
Why are some calories better than others?
Portion size of some foods are greater than the same calorie portion size of other foods. In other words, you can eat more for less. For example, two cups of strawberries contain the same number of calories as seven Gummy Bears.
What does 100 calories look like? Each item in the list below contains 100 calories.
- 2⁄3 baked chicken breast
- 2 cups strawberries
- 11⁄2 eggs
- 1 apple
- 1 med banana
- 1 large broccoli floret
- 1 scoop ice cream
- 1 tbs butter
- 6 tsp of sugar
- 3 squares milk chocolate
- 3⁄8 doughnut
- 7 Gummy Bears
Satiety – How Full for How Long
Some foods are more filling and last longer in the stomach than others. These calories hold greater value because they decrease further calorie consumption (you eat less).
Fiber fills you up faster with fewer calories and takes longer to digest so you feel fuller longer. It can be found in fruits, vegetables, beans, and whole grains.
Calories from protein increase fullness as well as metabolic rateii. About 30% of protein calories are used in its own digestion. Protein is also used to build muscles that burn calories even at rest.
Effect on Blood Sugar
A small pack (16 pieces) of Sour Patch candy (my personal favorite) only has 150 calories. Doesn’t sound like much, but all of those calories come exclusively from sugar with no other useful nutrients. This causes a spike in blood sugar producing large amounts of insulin, then a crash requiring more sugar to stabilize energy levels. These eating habits can lead to weight gain and health problems like type 2 diabetes.
Fiber helps reduce the uptake of sugar in to the blood stream. Calories from fiber are also filling and provide numerous health benefits. Sugar that is consumed along with fiber is released more slowly into the blood stream, keeping insulin levels stable.
Too much fructose (from added sugars, not the kind in fruit) can lead to insulin resistance and increased abdominal fatiii.
Weight management, optimal nutrition and disease prevention require more than simply counting calories. Different foods affect health in different ways. The list of benefits is enormous.
Fruits and vegetables are low in calories, high in fiber. They provide nutrients necessary for bodily functions and help protect from diseases like cancer. Berries, beets, and eggplants are sources of potassium which helps muscles contract. Fats such as olive oil, avocados, nuts, seeds, and almonds boost heart health. Green tea contains the highest amount of antioxidants of any tea. Studies show green tea may help fight prostate cancer and is associated with a reduced risk of stroke.
All calories are NOT created equal. The type of food calories come from is more important than the amount of calories consumed. For weight loss and health benefits, focus on nutrient dense food, not sugary items containing empty calories.
i Richard D Feinman and Eugene J Fine, “A Calorie is a Calorie Violates the Second Law of Thermodynamics,” Nutrition Journal (July 2004) 3:9
ii D. Paddon-Jones, “Protein, Weight Management, and Satiety,” American Journal of Clinical Nutrition (May 2008) 87:5
iii Peter J. Havel, “Consuming Fructose-Sweetened, Not Glucose-Sweetened, Beverages Increases Visceral Adiposity and Lipids and Decreases Insulin Sensitivity in Overweight/Obese Humans,” Journal of Clinical Investigation (May 2009) 119:5