This is interesting, and confirms my non-scientist’s suspicion. It turns out that (at least according to this one study) calories count, but not where they come from. The basic finding is that if you’re trying to lose weight, what matters is your total caloric intake (and output), rather than whether your calories come mostly from carbs, protein, fats, etc.
And if the exact source doesn’t matter much, then it doesn’t make much sense to force yourself not to eat things you enjoy just because they contain whichever nutrient (carbs, protein, fats, etc.) some supposed diet guru tells you is evil.
Of course, this study doesn’t prove that certain sources of calories don’t have a biological tendency to promote fat storage, etc. That might still be true. What the study does support is that in the lives of real people trying to lose weight, the source of calories doesn’t matter nearly as much as the total calorie count does. And surely that’s what really matters.
This finding raises interesting ethical questions, naturally, for those who promote particular diets, especially ones that have as their foundation an attempt to demonize particular sources of calories. If you’re promoting a low-carb diet, for example, this new evidence should give you pause.