Without getting involved in criticism of personal life styles, there is an important issue here that needs to be discussed
The OP is almost exactly twice the weight of the average passenger used in load sheet calculations. Given the rise in the overweight proportion of the population there are serious implications for the accuracy of the calculations with regard to performance and fuel burn.
In other forms of transport weight and bulk determine cost. In a system where excess baggage weight can prove extremely expensive, why should passengers be exempt from basic economics?
And that is before you consider the discomfort caused to their neighbours on the flight.