Intermittent Fasting Combats Cancer, Reduces Toxicity of Chemotherapy: Current Research


On Sept. 10, 2020, Fred Evrard, age 48, was diagnosed with stage 3 colon cancer. The tumor in his body reached about four inches in length.

As a strong, athletic martial arts instructor—with a healthy diet and lifestyle—the news came as a shock.

Overwhelmed and in excruciating pain, he lay in bed for three days without eating or drinking.

Three days later, Evrard was back on his feet ready to fight.

He began reading all about cancer and natural treatments. He found case after case of successful recovery and cancer reversal through fasting. These findings prompted him to try it himself.

Evrard embarked on a 21-day fast. His desire to live pushed him forward.

After 21 days of fasting, his MRI image showed a miracle: The length of the tumor on his colon had shrunk from four inches to less than 2 1/2 inches, and its diameter had also shrunk significantly.

With his fast over, he adopted a ketogenic diet, or more precisely, a carnivore diet. This was because he couldn’t eat anything with fiber because of severe intestinal inflammation. During that period, he also adopted intermittent fasting and ate only one meal per day.

During his battle with cancer, Evrard underwent three chemotherapy sessions. Fasting helped reduce the negative effects of chemotherapy so much that he hardly suffered side effects such as hair loss, nausea, or extreme fatigue. The immune indicators in his blood were also normal. During the second chemotherapy session, he tried to stop fasting and experienced severe side effects. He fasted again during his third chemotherapy session and achieved great results.

On Jan. 2, 2021, he started a five-day fast and a two-day ketogenic diet on weekends to complete the second round of a 21-day fast.

On Jan. 10, 2021, four months after being diagnosed with cancer, he underwent another MRI scan and blood test. The doctor told him with a smile on his face, “Mr. Evrard, you are cancer-free.”

How Does Intermittent Fasting Fight Cancer?

Since the early 1900s, scientists have noticed the positive effects of diet control on the health of organisms. Research at the time had already shown that diet control can slow or even stop tumor growth in laboratory mice, as well as delay cancer recurrence. Scientists have conducted hundreds of studies on different types of organisms, including yeast, nematodes, fruit flies, mice, rhesus monkeys, and so forth. After animal trials, small-scale human experiments were carried out. Preliminary studies suggest that prolonged fasting is safe for certain cancer patients and may reduce chemotherapy-related toxicity and inhibit the growth of cancerous tumors.

1. The Anticarcinogenic Actions of Fasting

Fasting and a ketogenic diet can put a person into a state of ketone body metabolism. Cancer cells can only survive by metabolizing glucose and glutamine, and they can’t metabolize ketone bodies. Therefore, such regimens are equivalent to cutting off the food ration of cancer cells.

Fasting and caloric restriction can reduce the production of growth factors, inflammatory cytokines, and anabolic hormones. That prompts corresponding changes in the body’s metabolism and hormone levels, such as decreased insulin secretion, increased insulin sensitivity, and decreased testosterone and estrogen secretion.

Fasting and restricting calories can also reduce oxidative stress even as they enhance antioxidant effects, reduce free-radical-induced DNA damage, and activate various DNA repair processes. Experiments on cells have also demonstrated that fasting and restricting calories can enhance autophagy, a process in which the body recycles cellular “garbage” and removes damaged cell parts. Fasting can also inhibit cell proliferation and slow down cellular aging.

These well-studied mechanisms may help the body fight cancer—as many studies suggest.

An animal study at the University of Wisconsin showed that monkeys that ate 30 percent fewer calories had a 50 percent reduction in the incidence of sporadic cancer (the most common of which is gastrointestinal adenocarcinoma) compared to monkeys on an unrestricted diet.

A study conducted by Johns Hopkins University with a median follow-up of 11 years found that intensive lifestyle intervention can reduce the risk of obesity-related cancers (including esophageal cancer, colon cancer, rectal cancer, kidney cancer, pancreatic cancer, stomach cancer, liver cancer, gallbladder cancer, thyroid cancer, uterine cancer, ovarian cancer, postmenopausal breast cancer, and multiple myeloma) by 16 percent. The researchers believe that this is due to the lifestyle intervention that led to the weight loss of the subjects.

joint study conducted by scientists in the United States and France found that a fasting diet combined with vitamin C can treat certain types of cancer more effectively.

2. Fasting Can Enhance Chemotherapy, Reduce Side Effects

Clinical research on fasting in cancer patients is still in its infancy. However, growing evidence shows that short-term fasting can reduce the toxicity of chemotherapy while enhancing the efficacy of chemotherapeutic agents, thereby improving the quality of life of cancer patients. This is because fasting increases the stress resistance of healthy cells, while tumor cells become more sensitive to chemotherapeutic agents due to a shortage of nutrients.

Animal experiments have shown that the inhibitory effect of fasting on tumors is comparable to that of chemotherapy; the combination of fasting and chemotherapy achieved the best anticancer effect and the most significant reduction in tumor volume. Moreover, such an approach produced the highest level of tumor-infiltrating lymphocytes. The experiments demonstrated that fasting also stimulated the production of common lymphoid progenitor cells.

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Animal experiments have shown that fasting combined with chemotherapy has the best anti-cancer effect. (The Epoch Times)

A small-scale clinical trial showed that short-term fasting reduces hematological toxicity in breast cancer patients receiving chemotherapy compared to the control group. The red blood cell and platelet counts increased significantly after chemotherapy, while the markers reflecting DNA damage increased relatively little, indicating that fasting may reduce the DNA damage caused by chemotherapy and promote its recovery.

A study involving 20 patients with various tumor types (mainly breast cancer, ovarian cancer, and uterine cancer) showed that compared with patients who fasted for 24 hours before chemotherapy, patients who fasted for longer periods (48 hours and 72 hours) had reduced rates of neutropenia and neuropathy, in addition to fewer increases in markers of DNA damage.

Another trial involving more than 30 gynecologic cancer patients showed chemotherapy patients who fasted experienced fewer headaches, weakness, and stomatitis. They also had significantly lower chemotherapy toxicity scores and fewer chemotherapy postponements. Additionally, patients who fasted had improved quality of life and reduced fatigue after chemotherapy compared to those on a normal-calorie diet.

Flora Zhao is a health writer for The Epoch Times who focuses on cancer and other chronic diseases. Previously, she was an editor for social science journals. Email her at:
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