ironmysocks

I have done many marathons, just signed up for my first trail 50k, and would like to do a 50 miler in the next year. I am currently running about 50 miles per week and plan to gradually increase that to 70-80. I usually place in the top quarter of my age group and would like to get better. I am a 5'9" female (age 35), 148lb, 23% BF, and believe that extra weight is holding me back. It seems that it is nearly impossible for me to lose fat while doing high mileage training (counterintuitive, yes). I tend to burn off muscle really easily, and arrive at the start line of marathons relatively "skinny fat" and weak. The only way I have ever had success losing fat is by doing a HIIT program along with clean eating. As soon as I switch the HIIT for running, my body covers itself in a layer of fat again. Does anyone have any advice on how, as a vegan, I can get lean while training as an ultrarunner? I think hormones probably have a role here, so a solution that works for a guy might not work for me.