There are proven environmental factors as well. Can diet help? Absolutely. I agree that some (I'm not a cancer expert, maybe they all do) cancers feed on sugars. That is seen in how we image some of them (PET). But there are also environmental risks that I don't think can always be overcome by diet alone. We need to address both. And even the dietary approach is probably more complicated than simply carb amounts. I'm sure there's a range of considerations like nutrients and what the carbs are replaced with (not all fats are the same, etc). Biochemistry is a complex topic. Food probably will get you 90% there though.
Discussion
Some very credible cancer experts are now saying that cancer feeds on glucose and if people don’t ingest exogenous glucose then cancer cells don’t have the necessary fuel to replicate. It’s very interesting.
glucose and glutamine
He has some interesting ideas. I've listened to some and have several more of his talks in my queue. Super interesting stuff.
I have bought into diet playing perhaps the most important role in cancer growth. I'm just not fully convinced it's the only factor involved in cancer development or cell damage. I do think that those other factors are edge cases though that account for small percentages of the problem. For example, radiation exposure, certain chemicals, etc. You may indeed hinder any resulting cancers, but we still need to address the things damaging cells. I think that gets missed when people say diet is it.