Mutagenics in Prepared Food

Consuming prepared meat increases the risk of contracting lung cancer   breast cancer prostate cancer   and colon cancer
This only means that prepared meat contains more mutagenic substances than prepared food. Of course vegetarians get cancer too, though in general a little less  , because vegetarians do consume prepared food, but no prepared meat.
Prepared vegetables contain less mutagenic substances than prepared meat. Therefore, 2 out of 3 scientific investigations show that consuming prepared Soya beans instead of prepared meat, causes less cancer. And therefore these scientists conclude that 'soy is protective against cancer'. This however only means that, on an average basis, soy (and other vegetables) causes less cancer than prepared food.
Generally, consuming vegetables ‘proves to be protective against cancer’, simply because consuming vegetables is less cancerous than consuming other prepared foods.

However ; all prepared foods (including vegetables) contain mutagenic substances. Foods increasing cancer risk the most, are prepared foods containing higher quantities of protein (like meat  and fish  , most fat  cholesterol (like eggs) or iodide (like sea-fish, crustaceans and mollusks)
Food that has been intensively heated, smoked  , or salted  , also highly increases cancer risk.

All prepared foods also contain non-HCA damaged protein, which is partly decomposed in the blood, originating free radicals. All prepared foods therefore will eventually cause cancer, ....if you live long enough.

Whenever again a scientific investigation proves that consuming vegetables is ‘protective’; remember that this only proves that a murderer is more criminal than a petty thief. And as releasing a petty thief does not prevent crime, consuming vegetables does not prevent cancer.
Vegetables are as healthy as 'healthy cigarettes containing 50% less mutagenic substances'.
Prepared vegetables are less cancerous than prepared meat, but to really lower cancer risk you should consume as little of all prepared foods. Consume as much fruits, some fresh raw animal food (like sashimi) and munch-foods to satisfy your cravings.