That's a common and unimpressive argument around plant based diets. Short of suicide, is it a choice that causes the least possible harm? Surely it causes less

That's a common and unimpressive argument around plant based diets. Short of suicide, is it a choice that causes the least possible harm? Surely it causes less suffering that farming all of those plants anyway, feeding them to other animals that take up more land and cause more pollution, and then killing those animals and eating them?