Prevention & lifestyle
Prevention, Seyfried says, “is never having to deal with what I’m talking about.” Everything comes back to protecting one organelle.
The wolf and the dog
His favourite illustration: cancer is the number-one killer of domestic dogs, yet wolves in the wild rarely get it. Same species - different environment. The wolf runs, hunts, and eats natural food; the apartment dog is sedentary, over-fed, and often obese. Modern humans, he argues, are the wolf that became the dog.
The six levers
Avoid highly processed carbohydrates
Especially high-fructose corn syrup and refined sugars - described as "the worst kind of crap".
Exercise regularly
The contrast of the active wild wolf (rare cancer) vs. the sedentary house dog (cancer is its #1 killer).
Prioritise sleep
Sleep is when the mitochondria restore their energy efficiency; poor sleep and sleep apnoea are risk factors.
Reduce chronic emotional stress
Chronic stress raises corticosteroids and blood sugar, feeding systemic inflammation. Music, meditation, friends and happiness all help.
Reduce carcinogen exposure
Microplastics, PFAS "forever chemicals", pesticides, arsenic/cadmium in water - all damage oxidative phosphorylation.
Consider periodic ketosis / fasting
Keeping the Glucose Ketone Index low periodically, the way our ancestors naturally cycled through scarcity.
The “how to get cancer” inversion
Seyfried relays a colleague’s tongue-in-cheek recipe for guaranteeing chronic disease - a checklist worth reading backwards:
“Eat crap food all the time, have terrible sleep, never get off the couch, doom-scroll all day, never exercise, and make sure you don’t have any friends or any happiness. You’re on a fast track - not only for cancer, but for all the other chronic diseases.”
Diet: more than one road
There is no single mandated diet - the goal is simply to keep the Glucose Ketone Index low and the mitochondria healthy. Approaches mentioned:
- Carnivore / low-carb - ribeye, lamb, bacon and eggs (Bartlett reached a GKI of ~10 after a week).
- Calorie-restricted Mediterranean - salmon, sardines, olive oil, avocado, plus exercise (used with success in the Greek glioblastoma group).
- Plant-based - achievable too; the target is the metabolic state, not the food tribe.
- Avoid - high-fructose corn syrup, refined sugar, ultra-processed carbohydrates, and constant snacking.
On individuality and humility
Seyfried stresses metabolism is individual - age, sex, genetics and comorbidities all change where a food lands you on the chart. He is careful not to tell people what to eat: the point is to give people the knowledge and the measurement so they can decide for themselves, ideally with a clinician. He also declines to endorse GLP-1 drugs (e.g. Ozempic) for this purpose - they lower blood sugar, but their effect on ketones and mitochondrial health hasn’t been studied.