I'm so sick of reading these oversimplified "a calorie is a calorie" fallacies as if they're simply burning up foodstuffs in a bunsen burner in a lab, neglecting that we're instead dealing with biochemical reactions from ingesting various foods in an organic, living human body. If parts-is-just-parts, then why does 6 ounces of water react differently inside our body than, say, 6 ounces of strictnine/poison? Because the body reacts differently to different substances (duh!).
If they honestly think that my eating 2000 calories of chocolate sundaes on a given day produces the same results to my dietary progress as 2000 calories of nutritious low-carb meals, these low-fat diet authors really must have permanent high-carb brain-fog compromising their thinking patterns.