There are foods on which the standard processes don't accurately measure energy content. Or at least, certain manufacturers tell us that. Not sure if to believe

There are foods on which the standard processes don't accurately measure energy content. Or at least, certain manufacturers tell us that. Not sure if to believe them or not. Example: Quest bars. Their syrup would typically show 4 kcal per gram, but is actually closer to 2. Supposedly. That's how a bar can have so few calories and such good macros. Ultimately, if you're consistent with tracking your calories and its effect on your weight, it doesn't matter if the values are off by 20, 30, or 50%. Just be consistently off by... 50%.