I have no problem with a high vege diet I'd say 70% of my calories currently comes from vegetables/vegetable juices. I don't eat fruit. No one will "die" on a high vege diet. On the contrary, we should all eat more of them to live well! :o)
But, a handful of seeds, though it contains some protein and SOME amino acids, does not contain complete protein. A mix of pulses, seeds and nuts does, and should contain all essential amino acids...ie complete protein. This isn't a lie :o)