You can't go anywhere without being confronted by calories. Restaurants now print calorie counts on menus. You go to the supermarket and there they are, stamped on every box and bottle. You hop on the treadmill and watch your "calories burned" click upward.
The more calories we take in, the more flab we add—and if we cut back on them, then flab starts to recede too, right? After all, at face value, calories seem to be the factor by which all foods should be judged. But if that were true, 500 calories of zucchini would equal 500 calories of Oreos.
But what are calories?
A calorie is simply the unit of measurement for heat defined in the 19th century; it is defined as the amount of heat required to raise 1 gram of water by 1 degree Celsius.
The USDA introduced the calorie as the unit of measurement into food world around 1890. Scientists of the day would literally set a food item literally on fire, and measure how well the flaming sample warmed a water bath.
Today, a food's calorie count is calculated from its carbohydrate, protein, and fat content.
Myth #1: Calories Fuel Your Body
Actually, they don't !
Why? Simply because a calorie is NOT a source of energy but the unit of measurement for heat.
Instead of heat, your body runs on chemical energy, fueled by the oxidation of carbohydrates, fat, and protein.
The oxidation occurs in your cells' mitochondria; the several billion small power plants.
What should you do with calories? Track the content of carbohydrates, fats, and protein—not just calories—when you're evaluating foods.
Myth #2: All Calories Are Created Equal
Not at all !
Your fuel comes from three sources (macros): carbohydrates, fats and protein.
A gram of fat has about 9 calories
A gram of carbohydrate has about 4 calories
A gram of protein has about 4 calories
In other words, you could eat twice as much carbohydrates or proteins as fat for the same amount of calories. That explains clearly why ketogenic meals are half the size as carby meals.
"Calories in, calories out" claim is misleading. Each of the macros are handled by the body differently, and have different effects on the energy equation.
Carbohydrates and fat yield more usable energy than protein does. Here is why:
For every 100 fat calories you consume, your body expends 3 calories in digestion.
For every 100 carbohydrate calories you consume, your body expends 5-10 calories in digestion.
For every 100 protein calories you consume, your body expends 20-30 calories in for digestion.
Myth #3: A Calorie Ingested is a Calorie Digested
It's not that simple !
Just because the food is swallowed doesn't mean it will be digested. It passes through your stomach and then reaches your small intestine, which slurps up all the nutrients it can. 5-10 percent of calories slide through unabsorbed.
Fat digestion is efficient—fat easily enters your intestinal walls.
As for protein, animal sources are way more digestible (bio available) than plant sources. A protein from a steak is way better absorbed than tofu's.
Different carbs are processed at different rates, too: Glucose and starch (pure glucose) are rapidly absorbed, while the insoluble fiber in complex carbs (those in vegetables and whole grains) block the absorption of calories. With a very high-fiber diet, say 60 grams a day, you might lose as much as 20 percent of the calories you consume.
A reliable measure of calories is difficult. A piece of rock candy and a piece of broccoli have the same number of calories. Nevertheless, the vegetable fiber contributes roughly twice as few calories.
Myth #4: Exercise Burns Most of Our Calories
Not even close !
Even the most fanatical fitness nuts burn no more than 30 percent of their daily calories at the gym.
Most of your calories are burn at a constant simmer, fueling the basal metabolic processes that keep you alive—replacing old tissue, transporting oxygen, mending wounds, etc. About 70 percent of your total caloric expenditure goes toward your bodily functions. This translates into roughly 11 calories per pound of body weight a day. For example, a 200-pound person will incinerate roughly 2,200 calories a day—even if he/she sat in front of the TV all day.
And then there are the calories you lose to N.E.A.T., or non-exercise activity thermo-genesis. N.E.A.T. consists of the countless daily motions you make outside the gym—the calories you burn while spending time on your feet, making breakfast, walking, or chasing the bus. A conscious effort to spend more time on your feet might net a greater calorie burn than 30 minutes of daily exercise.
Myth #5: Low-Calorie Foods Help You Lose Weight
Not always !
Processed low-calorie foods are without a doubt weak allies in the weight-loss war.
Take sugar-free foods. Omitting sugar is the easiest way to cut calories. But food manufacturers generally replace those sugars with calorie-free artificial sweeteners (such as sucralose or aspartame).
A University of Texas study found that consuming as few as three diet sodas a week increases a person's risk of obesity by more than 40 percent.
A 2008 Purdue study found that rats that ate artificially sweetened yogurt took in more calories at subsequent meals, resulting in more flab.
The theory is that the promise of sugar—without the caloric payoff—may actually lead to overeating.
Conclusion
Eat right and perform better.