UCSF’s Dr. Robert Lustig was recently on the Colbert Report to debunk some common nutrition dogma: A calorie is a calorie (and it doesn’t matter if those calories come from carrots or cheesecake).
Here are just four examples that refute this idea (from Dr. Lustig’s article in the Huffington Post):
- Fiber. You eat 160 calories in almonds, but you absorb only 130. The fiber in the almonds delays absorption of calories into the bloodstream, delivering those calories to the bacteria in your intestine, which chew them up. Because a calorie is not a calorie.
- Protein. When it comes to food, you have to put energy in to get energy out. You have to put twice as much energy in to metabolize protein as you do carbohydrate; this is called the thermic effect of food. So protein wastes more energy in its processing. Plus protein reduces hunger better than carbohydrate. Because a calorie is not a calorie.
- Fat. All fats release nine calories per gram when burned. But omega-3 fats are heart-healthy and will save your life, while trans fats clog your arteries, leading to a heart attack. Because a calorie is not a calorie.
- Sugar. This is the “big kahuna” of the “big lie.” Sugar is not one chemical. It’s two. Glucose is the energy of life. Every cell in every organism on the planet can burn glucose for energy. Glucose is mildly sweet, but not very interesting (think molasses). Fructose is an entirely different animal. Fructose is very sweet, the molecule we seek. Both burn at four calories per gram. If fructose were just like glucose, then sugar or high-fructose corn syrup (HFCS) would be just like starch. But fructose is not glucose. Because a calorie is not a calorie.