I used to be in the Vegetarian Cycling and Athletic Club and in its early days its cyclists were often criticised when entering events because it was felt their diet gave them an unfair advantage.
It is easy to replace high satiety protein with too many processed carbs as PP2 was finding. You shouldn't eliminate them but choose wholegrain or less processed ones and ones that release sugar slowly such as oats. Some of Scott Durek's ingredients are expensive and hard to source but things like avocado and nut butters are easy enough to get hold of.
PP2 - good luck with your ideas. I'm sure you'll find the benefits. It's a matter of taking more care daily and almost meal by meal about the balance of nutrients you're taking in. Add protein whenever you can. For vegans something to be very careful about is getting enough omega 3 fatty acids and vitamin B12. Long chain omega 3s are completely absent in a plant based diet although slightly inferior short chain ones can be found in oils such as hemp or flaxseed. B12 is also not present, although it might be in some seaweeds, but who wants to eat seaweed? Brewer's yeast contains a lot of it so if you don't like it at the moment, you're going to have to get to like Marmite!
Such a shame when someone posts a genuine query who then gets pounced on by people who don't really know what they're talking about or think it amusing to be insulting.
This seems to be happening a lot lately, often by the same group of folks.
Assuming this thread is still just about hanging on to life, I can report I'm a vegetarian and for the last 16 years mostly vegan. I have found it very beneficial to give up bovine milk protein but still eat hard cheese the making of which seems to break down casein to a large extent, and goat's milk products.
It's also hard to avoid compromising the diet when eating out. When presented with a menu that only has the dreaded vegetarian lasagne on it, it's then a tad difficult to ask if they do a non-dairy vegetarian lasagne ...
Scott Jurek's case is very interesting. His performances showed huge improvement when he started a vegan diet, or as he calls it 'plant based'. The meals provided during the recent Dragon's Back ultra were all vegetarian because the RD considered this food the most suitable for extreme endurance events. the rations on Ranulph Fiennes and Mike Stroud's unsupported crossing of Antarctica were vegetarian for the same reason.