A calorie is a measure of the amount of energy and it is always the same. It has always been defined in this manner. Amino acids, carbohydrates and fats are all metabolized using different pathways, and yes, there will be different efficiencies for each. But the untrained person rarely understands the difference between a calorie, and the efficiencies of that calorie.
Not some laboratory equation or a law that appears to not be really relevant to the discussion.
So if an overweight person consumes 1,200 calories a day, while burning 1,500 calories a day, over an extended period of time, they won't lose weight? How does that work?
The article referenced in the NYT's is interesting but it certainly does not deny thermodynamics. Yesterday, a meta-analysis was published in JAMA that indicates the source of the calories doesn't matter when it comes to weight loss. The conclusion of the study was that significant weight loss can occur with any low-carbohydrate or low-fat diet. People should use whatever diet works for them instead of debating which one is best. That's because if you burn more energy than you consume, you will lose weight. Same as it ever was.
Nobody is saying that couldn't work. What we are saying is that a diet low in carbs, while even consuming more calories, said person could lose even MORE weight and faster! When it comes to burning fat cells, a calories is not a calorie. On top of that, the blood work would be improved and the threat of heart disease lessened.
Hear this man and thank you for citing a scientific, refereed journal and not some tabloid like the NYTimes.