In my data (8k females and 23k males), sexually submissive females reported weighing 10 pounds less than dominant females, and submissive males reported weighing 13 pounds more than dominant males.
Why do you think this might be?
If submissive men are on average shorter and heavier, it might indicate a tendency away from self discipline, or the preference for external forms of discipline.
Making male subs substantially less "fit" - shorter and weighing more.
Dom F & Sub M are counter gender norm
as are "big" F and "chubby" M
This data very much fits expectation