You Can't Blame McDonald's Alone

Consider the case of John Wilson Webb, just shy of three years and already a whopping 120 lbs. I'm not trying to be mean here, just trying to understand how a toddler can weigh 33% more than a large sack of concrete. I weighed 120 lbs. when I was fourteen, a freshman in high school, and was 5' 8" tall. Someone explain this to me, because I think the doctor must have had his foot on the scale.