Byron's BMI

According to today's Guardian, Lord Byron was actually "overweight and unattractive".  This seems like nonsense.  The evidence is his weight.  He is described as five eight (a handsome size at that time), and weighing in at 76 kg, described as "borderline obese".  Not so.  According to the NHS site which calculates such things, Byron's BMI would have been 25.48, or, very borderline overweight - not the same as obese, and close to a healthy weight.  Byron may have had a slight paunch, but he was no Arbuckle.  If he was in fact 13 stone (another figure mentioned) he would have been 29 on the BMI scale; 30 is obese - but this might have been with his heavy medical boots on.  At 23, he weighed around 63 kg, which would have made him a very slim weight.  This seems like a story without much weight to it.