Interesting, joebloggs, but I think vegetarians ( who don't consume meat, poultry, fish or seafood ) and vegans ( an even stricter sub-category who don't consume any animal products or by-products, in some cases not even honey / yeast ) will always form a minority in any population, for various reasons including choice and cost. They are probably less than 10 % of the UK population.
Certainly adoption of a " Western lifestyle " is responsible for a similar pattern of diseases - heart / circulatory / cancer - in both our countries ( http://mariaespievidal.com/obesity-a...-by-filipinos/ ).
The recent British Journal of Cancer study estimates for men about 6% of cancers are linked to lack of fruit and vegetables, 4% to obesity; for women 3% to lack of fruit and vegetables, and 7% to obesity ( because of the effect on breast cancer ).
As always, however, the effects of lifestyle on our health is complicated and involves an element of luck ! Cancers are caused by multiple factors acting at the same time, and that's why even this comprehensive study could find less than half of all cancers were due to avoidable life choices.