The plant-based M.D, and author of How Not To Die, puts forward studies showing that cancer can actually feed on ketones - and that they have been found to actually fuel human breast cancer growth and drive metastases.
Greger also points out how breast cancer often metastasizes to the liver, which is the main site of ketone production - but states this is purely speculation.
"Promoters of ketogenic diets for cancer paid for by so-called 'ketone technology' companies, that will send you salted caramel bone broth powder for a hundred bucks a pound," Dr Greger states.
"Or companies that market ketogenic meals report 'extraordinary' anecdotal responses in some cancer patients but more concrete evidence is simply lacking."
Dr Greger adds: "Even the theoretical underpinnings may be questionable. You know, a common refrain is that 'cancer feeds on sugar', but all cells feed on sugar.
"Advocating ketogenic diets for cancer is like saying Hitler breathed air - so let's boycott oxygen."
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