Discussion on question by iFlo: How to tell an overweight person that the hike will be too hard?

I'm overweight for my height but I'm physically fitter than most people who weigh less than me. Weight isn't the issue, fitness is what you're going for my friend.

It sounds to me like this is simply an information problem - she doesn't know what she's getting into. If she knew, she would conclude herself that this is something she doesn't want to do (because if this were the kind of thing she wants to do, she'd already be doing more things like it).