[jackvalentine]

So I went looking for any studies about peoples ability to estimate calories, since any under/over estimation compounds either way in terms of results.

It turns out like everything, that's a tricky thing to study. When people are aware that their meals are going to be scrutinised they change what they eat for the duration of the study.

I wasn't able to find a recent study that investigates people's ability to estimate calories and the variance in their estimations.

> You seem to believe that any kind of "back of the envelope" / "ballpark" calculation is useless.

I do think that anything above a "good, bad, not sure" estimate is probably going to be so inaccurate as to not be worth the effort. However the act of trying to count calories itself promotes a mindfulness of what we're eating and that can induce change.