The trouble is that when people choose to be vegan they just omit all animal foods and alot i know end up on beans and rice - filler foods.

Of course you're bound to run into problems having just these kinds of foods as a vegan.

A true vegan diet is all supportive nutrition from non animal sources - and one can thrive on that diet...as many have for thousands of years.

So instead of scare-mongering your friend why not suggest to them they research actual nutrition needed by the body before deciding what vegan foods to eat. This education is needed by most people as the SAD diet is just that - leaves you sad n miserable because you're under-nourished.