[mi100hael]

The "calorie is a calorie" argument is true in that

    weight gain/loss == surplus/deficit intake

Your point about sugar fucking with insulin balance and its addictive properties are good points, but not directly related to the study at hand. Western prepared foods are loaded with added sugar, but it's completely possible for obese people to eat a complete diet of home-cooked meals in surplus using only fresh, raw ingredients without a gram of added sugar. It's also completely possible for skinny people to eat shit food and not get fat. The researchers should have controlled for body fat % and diet, which would not have been challenging. Instead it seems they've chosen to completely conflate the two key factors.