[adrian_b]

An adequate daily protein intake from food cooked from vegetables that have not been processed using special methods for protein separation would provide over 3000 kcal/day.

Using so much energy requires many hours of intense physical activity. When your job requires spending 8 hours or more per day sitting in front of a computer, then it is absolutely impossible to also do enough physical work to consume over 3000 kcal.

Therefore your suggestion is also a non-solution for many people.

It is true however that for most of our ancestors the problem of gaining weight when eating a strictly vegan diet would not have existed. This is indeed just a modern problem, of the sedentary people.

For instance, bread is normally considered to be an incomplete source of proteins, but that is just because one cannot eat enough. Eating bread made from 1 kilogram of flour per day provides enough of all essential amino-acids. It also provides about 3500 kcal/day. Someone doing hard physical work, like it was much more common in the past, could eat only bread without needing any other source of proteins.

[bartonfink]

You can use a lot of words, but it doesn't change the underlying fact that you're too lazy to make your dietary principles really work. Burning 3000 calories a day while working in software is absolutely possible. I did it today.