How many peanuts did you snack on last week? If you don't remember, you're not alone. We humans are notoriously bad at remembering exactly what and how much we ate. And if there's one pattern to our errors, it's that we underestimate — unintentionally and otherwise.
And yet, for decades, researchers who want to amass large quantities of data about how much Americans eat and exercise have had to rely on individuals to self-report this information.