I never quite reached 300 but got uncomfortably close--and after and injury and a bunch of setbacks, I am too close again.

I Love biking. Pulling all this extra weight Really sucks, the hills are deadly (barely an exaggeration---I have learned to listen to my heart and quit before it does.) But there is no reason a big guy cannot enjoy rising a bike---and almost all the gear I use is Not rated for the load I put on it. The idea that if you weight 275 you can ride 32-spoke wheels but if you weight 276, all the spokes will pop, so go to 36 ..... yeah, okay.

When I was fit and doing fully-loaded touring, i weigh maybe 170-175 and the bike weighed 30 and the gear weigh 90, if I was carrying full food and water for primitive camping---in other words, 300 pounds. Never an issue with wheels, frame anything.

A good bike should hold up.

And yeah, I did blow though a lot of cheap bikes--twisted the cranks off the chain ring once, broke a lot of wheels bashing curbs (can't bunny-hop with 40 pounds of gear on the rear axle) and wore out every bearing surface (monsoon rains and insufficient time for maintenance.) But that was me riding all-out, with no respect for the bike, over bad terrain, with a heavy load .... if I had just normally ridden the bike and cared about not abusing it, I bet most of the bikes I build would have lasted.

I'd suggest the couple buy a couple of cheap bikes and wear them out. if they like riding, they can decide what to do next.

However ... as [MENTION=484412]livedarklions[/MENTION] can aver, riding a bike won't take or keep the pounds off. Exercise ios good for helping keep the body going, by temporarily increasing metabolism, blood flow, all that ... but cutting calories is what cuts weight. There is no way to exercise off 1000 calories unless a person is already in really good shape.

But riding a bike can improve quality of life, and that makes everything else easier.