I went totally plant-based last year after seeing a presentation on PBS by Dr Bonard. I was already eating mostly vegetables and a little bit of meat, so it wasn't much of a hardship to switch. I was clinically obese, and still am, so I'd have to say that going plant based isn't necessarily going to change that. My blood pressure is way down, so that is reason enough to stick with it. I do several centuries each summer, so it is definitely possible to fuel these efforts with plant based foods. I'd also point out that horses--the greatest endurance athletes in the world--can get fat by eating too much grass. So, the notion that animal based proteins are necessary for performance is clearly not true, but also this demonstrates that weightloss will not naturally happen just by going vegan.