In my column this morning, I mention that the average 18-year-old today is 15 pounds heavier than the average 18 year-old in the late 1970s. Adults have put on even more weight during that period. The average woman in her 60s is 20 pounds heavier than the average 60-something woman in the late 1970s. The average man in his 60s is 25 pounds heavier. When you look at the chart, you start to understand why.