SEIs are sometimes stereotypically typed as overweight people. I'm wondering: in which ways would an ILE support an SEI that wants to lose weight?

To put it more specifically: my GF is overweight, wants to lose it, but has issues with her knees, so the more standard ways of exercise are painful for her. Imo, she needs to exercise in a way that burns fat, but doesn't strain her joints, so e.g. swimming would be ideal. And although she already swims at least once a week, she is not going to strain herself to a heart rate that will actually start burning fat. She would rather focus on a wheat-free diet, which she has been doing for years with no lasting results.

My recommendations fall on deaf ears. How would an ILE go about it? Would they be supportive of weight loss at all?