A nice interview in the NYTimes today with a Rockefeller University researcher who has been studying obesity for decades. The key point he makes, which people must understand as a baseline for a discussion of diets, is that ultimately a calorie is just a calorie, whether you get it from proteins, fats or carbs.
Perhaps the most important illusion is the belief that a calorie is not a calorie but depends on how much carbohydrates a person eats. There is an inflexible law of physics — energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged. Calories leave the system when food is used to fuel the body. To lower fat content — reduce obesity — one must reduce calories taken in, or increase the output by increasing activity, or both. This is true whether calories come from pumpkins or peanuts or pâté de foie gras.
To believe otherwise is to believe we can find a really good perpetual motion machine to solve our energy problems. It won’t work, and neither will changing the source of calories permit us to disobey the laws of science.
So there are no “Good calories and Bad Calories” in the sense of how those calories influence your weight directly. What Gary Taubes and other are talking about is the effect of calories on the mind. Certain kinds of foods make it easier to eat fewer calories, and some make it harder. But in the end, eating 500 “bad” calories is not going to make you put on any more weight than eating 500 “good” calories.
It’s like the old riddle: what weighs more, a pound of rocks or a pound of feathers?