Raw vegan experts claim foods lose many nutrients when they are heated over a certain temperature. Also the way you heat them can have an even bigger impact (i.e. boiling instead of steaming, frying to a crisp instead of lightly sauteeing).
So actually it's not just about avoiding additives, some food loses nutrients when it is cooked. HOWEVER (big however
) some nutrients are actually more bio-available in foods after being cooked. For example tomatoes when cooked release considerably more lycopene, which is considered one of the most powerful antioxidants. Spinach also is better cooked as it destroys some of the phytic acid which makes the iron, magnesium and calcium in spinach much more bioavailable (but overall you do still lose some vitamins).
I did raw veganism as a diet before I turned vegan and I felt amazing but then I tried it again since becoming vegan and I didn't get the same high, I really just felt like I was missing a lot of vitamins. Raw vegans will say probably I was doing it wrong but I think raw veganism doesn't work for everybody and on the contrary, eating so much fruit can have a negative effect on may people's digestion (problems with candida etc). Fruit is still sugar, I don't get why anyone would advocate eating so much sugar, I personally feel bad if I eat large amounts of fruit and few veggies or tofu.
Anyway that was very long sorry..Hope some/any of that was useful!
