Fasting May Offer Breakthrough in Cancer Treatment, Experts Say

What we eat plays a pivotal role in our health and well-being, particularly in the development and treatment of chronic diseases like cancer. Recent discussions among medical experts suggest that strategic fasting might help put the body into a regenerative state that could enhance cancer treatment while reducing side effects.

During a recent episode of “The Dr. Hyman Show,” Canadian physician, author and researcher Dr. Jason Fung joined host Dr. Mark Hyman to discuss how fasting might help reverse diseases such as cancer by fundamentally changing how cells operate within the body.

“The whole idea of fasting is that you’re trying to put the body into this sort of regenerative maintenance mode,” Dr. Fung explained. “Because what we’ve recognized is… you can go into growth mode, or you can go into sort of this cell maintenance repair mode.”

This cellular response depends largely on nutrient availability. When nutrients are plentiful, cells are programmed to grow. Without nutrients, the body shifts into a state of maintenance and repair, essentially giving cells time to recover rather than constantly expanding.

Dr. Fung compared this process to maintaining a car engine. Just as constantly running an engine at high speeds will cause it to burn out faster, the human body needs periods of rest and repair for optimal function.

“You can go for growth, or you can go for longevity or cellular maintenance, but you’ve got to have a bit of both. It’s a balance there. It’s not all growth,” he said.

This balance becomes particularly crucial when fighting cancer, a disease characterized by uncontrolled cell growth. According to Dr. Fung, eating during cancer treatment may inadvertently promote cellular growth at a time when stopping such growth is the primary goal.

“You’re basically feeding into that growth,” he warned. “And that’s going to be very, very bad for you.”

Research has found that fasting before, during, and after chemotherapy can significantly reduce side effects by slowing down cell division in healthy tissue. Chemotherapy targets the body’s fastest-growing cells, which typically include hair follicles and the gastrointestinal tract lining—explaining why hair loss and nausea are common side effects.

“If you can put those cells into a quiescent sort of repair mode, [they’re] not going to sustain as much damage from the chemotherapy,” Dr. Fung explained. “And instead, the cancer cells—which can’t stop their growth, they’re always trying to grow—they can’t do that. So, therefore, they’re going to sustain full damage from the chemotherapy while your body is relatively protected.”

Dr. Frank Dumont, an internal medicine physician and executive medical director at Virta Health in Colorado, added valuable context to the discussion. As a specialist in using nutrition to improve metabolism, Dumont noted that the metabolic benefits of fasting can sometimes be achieved through other dietary modifications.

“There is tremendous overlap between the metabolic benefits of fasting, or time-restricted eating, and making adjustments to macronutrients in the diet, such as decreasing carbohydrate intake when appropriate,” Dr. Dumont explained.

These nutritional changes can produce similar physiological responses: “When you do that, glucose levels start to go down, insulin levels go down, inflammation goes down.”

According to Dumont, the approach should be personalized: “You can either adjust what you’re eating, or you can do things like restrict how much or when you’re eating. How you do that depends on what makes the most sense [for] your situation and what you can tolerate.”

The connection between metabolism and cancer lies partly in insulin’s role. When insulin levels rise, leading to insulin resistance and metabolic dysfunction, this can stimulate growth in certain cancer cells. Additionally, some cancer types rely almost exclusively on glucose for energy, unlike healthy cells that can utilize fat, fatty acids, and ketones as alternative fuel sources.

“The bottom line is, our body is much more flexible,” Dr. Dumont said. “If you can start to get the nutrition to match up with the metabolism, that often means lowering the glucose intake—and, in a way, starving the cancer.”

This approach represents a potential dual benefit: supporting the body’s health while placing cancer cells at a disadvantage. “You can take care of your body and actually put the cancer at a disadvantage at the same time,” he concluded.

As research in this area continues to evolve, these insights offer promising avenues for integrating nutritional strategies into conventional cancer treatment protocols, potentially improving both outcomes and quality of life for patients.