Someone who is physically fit can have a high BMI due to having greater than average muscle mass.

FORBES: How Useful Is Body Mass Index In Predicting Long-Term Health?

Health Commission Wales told the Politics Show there is clear evidence that patients with a high BMI have a higher rate of surgical complications.

BBC: NEWS | Programmes | Politics Show | Wales: NHS operations withheld

Moreover, the increasing prevalence of high BMI in childhood is a worrying phenomenon, since early onset means living with obesity and its metabolic consequences virtually for a lifetime.

FORBES: How Useful Is Body Mass Index In Predicting Long-Term Health?

This is known as a high body mass index, or BMI.

FORBES: Magazine Article