Answer
Ive never eaten sand, but it seems bart is the expert.well, you should come to the southeast, a lot of people will recomend the northeast but the south is a lot more developed.rio has plenty of veggie places, my sister is vegan and lived there for a lot time.but its a crowded big town.i always suggest buzios (www.buziosonline.com.br)its 2 hours north of rio, a peninsula with some 25 beaches, safe and extremely tourist oriented.there are some 300 inns and b&b.my favorite are:www.abracadabrapousada.com.brandwww.casasbrancas.comboth supperb, the first with a younger crowd.in buzios you wont have problems to find veggie places to eat, nor in rio.even the giant bbq houses in brazil have massive salad buffets, really massive.in buzios check out a restaurant/kiosk in praia brava (best beach for me, not tourist at all) called camarÃo preto (black shrimp). they have amazing veggie dishes.the blokeager, pauline, an argentine girl, is amazing, she makes you feel at home as soon as you arrive. the bartender alex is quite a caracter .enjoy, i´ve been going to buzios since i was a kid and its a magical place.