You may want to pick up the college textbook "Ninth Edition, Nutrition for Health, Fitness & Sport," by Melvin H. Williams. This textbook covers among other things plant-based nutrition for athletes and will provide you with the answers you seek based on recent studies. You may also want to pick up a copy of the original book "The McDougall Method." In my opinion, this is a great book for athletes (since we are not interested in the "Maximum Weight Loss" book for fat people).
Basically, if it is a whole plant, eat it.
You want to maximize getting all your vitamins and minerals, your essential fatty acids, and your essential amino acids -- easily done on a whole plant-based diet (although you do need to eat more plant protein since it is harder to assimilate than animal protein, but as the text will point out, among other things, we don't really need all that much protein -- a recent study, for example, shows that athletes actually need less protein than the non-athletes because in pertinent part the athletic body does a great job retaining protein).
A good rule of thumb is to eat at least 300 grams of starch-based carbohydrate to keep your glycogen reserves up, and you need no more than about 85 grams of plant protein (50 of animal), and then you could add in an oz of nuts, and an avocado for your salad, and eat some more grain if you need 4000 calories -- that would add up to a lot of fat! In other words, I don't think we need to be thinking in terms of "fat" -- just in terms of eating lots of variety of any whole, unrefined plant-based food. QED