Frame material really doesn't mean as much as a lot of people think. How a bike is put together means so much more. Just saying that you need steel is a red herring as an alloy bike built one way can be a much better bike than a steel bike built another way. There are so many tube profiles and thicknesses in alu/steel/titanium/carbon that you just can't make blanket statements. True, the different materials have properties that make them better suited to different uses, but you have to build it right to make it work that way.
I have a carbon road bike (had 2x carbon and 2x alu in my time), an alu track bike (2x alloy and 2x carbon in my time) and a steel MTB (previously had an alu) for the record. I currently sit at 6'5" and 285 and have been as much as 310 while riding and I don't hold back either.