For decades, the prevailing medical wisdom has treated cancer primarily as a ‘genetic lottery’ — a series of unfortunate mutations that trigger uncontrollable cell growth. However, Dr Thomas Seyfried, a professor of biology and genetics at Boston College, has challenged that narrative by focusing on what cancer cells eat rather than just their DNA.
In an appearance on the October 7, 2024, episode of The Diary Of A CEO, Dr Seyfried argued that cancer is not merely a genetic fluke, but a metabolic disease that thrives on specific fuels. According to his research, he shared the secret to halting tumour progression lies in a simple, non-toxic strategy: cutting off the supply lines.
He said, “We published one of the first ever papers linking that the higher your blood sugar, the faster the tumour grows. The lower the blood sugar, the slower the tumour grows. Undeniable. A normal cell becoming a cancer cell doesn’t happen overnight. All we have to know about cancer is how it is growing so rapidly. Why are they going out of control? How come it’s so hard to kill them?”
The two pillars of tumour growth
Dr Seyfried shared that while healthy cells are metabolic ‘hybrids’ capable of burning different types of fuel, cancer cells are remarkably rigid. To grow at such aggressive speeds, Dr Seyfried said they rely almost exclusively on two sources:
⦿ Glucose: sugar derived from carbohydrates and high-glycemic foods.
⦿ Glutamine: a common amino acid found in proteins.
Starving the ‘broken’ mitochondria
The core of Dr Seyfried’s theory rests on the health of mitochondria — the power plants of our cells. He argued that cancer cells possess ‘bad’ or dysfunctional mitochondria that cannot effectively process fats for energy. He said that by shifting the body into nutritional ketosis — a state achieved through water-only fasting or ultra-low-carbohydrate diets — healthy cells begin to burn ketone bodies for fuel. Because cancer cells cannot make this metabolic switch, they are left ‘starving’ in a fuel-restricted environment, he said.
Dr Seyfried explained: “A solution to the cancer problem without toxicity is to simultaneously restrict the two fuels: glucose, which is already in our bloodstream from the food we eat, and the amino acid glutamine. If we stopped eating, adopted a low-carbohydrate diet, and did water-only fasting, we would enter nutritional ketosis. The tumour cells have bad mitochondria. They’re dependent on glucose and glutamine. We can replace glucose and glutamine with ketone bodies. So, we selectively marginalise these tumour cells slowly over time. They slowly start to die. The blood vessels disappear, and the body comes in and dissolves them.”
A shift toward non-toxic management
Perhaps the most provocative part of Dr Seyfried’s message is the call for a ‘solution to the cancer problem without toxicity’. Traditional treatments like chemotherapy and radiation target rapidly dividing cells, but often cause significant damage to the rest of the body.
Dr Seyfried suggested that by managing metabolic health, we can create an internal environment where cancer simply cannot survive. He added, “Cancer is very preventable. It’s just that we’re doing everything we possibly can to induce it.”
While Dr Seyfried’s metabolic theory offers a hopeful path for dietary intervention, it remains a controversial departure from standard oncology. For those looking to improve their metabolic health, he shared that the journey begins with controlling blood sugar and understanding the fuel we provide our bodies every day.
