A recent study has shown that short term fasting while undergoing chemotherapy enhances health related quality of life in patients with early breast cancer, with no negative side effects. This research was presented at the European Society for Medical Oncology (ESMO) Congress 2023.

According to congress presenter Daniela A. Koppold, MD, Charité University Medicine Berlin, Germany, "Strikingly," fasting also appeared to prevent fatigue, something patients with breast cancer struggle with”.

Earlier research has shown that fasting around chemotherapy cycles can reduce toxicity and negative side effects associated with chemotherapy.

Another presenter, Jann Arends, MD, at Freiburg University Medical Center, Germany, said that the findings fit "very well" with previous studies. "Short-term fasting in subjects not at risk for malnutrition is feasible, well tolerated, and appears to improve several parameters of quality of life," he said.

The researchers assessed health related quality of life using the 27 item Functional Assessment of Cancer Therapy General (FACT-G). It measures physical, social, familial, emotional, and functional well-being.

These research findings support fasting for 60 to 72 hours around chemotherapy for patients with breast cancer who can experience faster recovery from chemotherapy and better quality of life. It’s important to consider the patient’s nutritional status of course. Patients who are under weight or suffer with nutrient deficiencies may not be suitable candidates for fasting.

Fasting can have a great deal of health benefits; particularly weight loss in overweight people, improved immune function and improved gut health, whether a person is undergoing chemotherapy or not. Ordinarily, your body breaks down carbohydrate into glucose to provide you with energy. When your body doesn’t get enough carbohydrate or calories for energy, it begins using fat cells for energy. Intermittent fasting or prolonged fasting triggers your body to burn stored fat for fuel because it’s not getting as much carbohydrate. When stored fat is broken down, your body produces ketones. These serve as an alternative fuel source when glucose is in short supply. An elevation of ketones in the body is called ketosis and is the goal of a ketogenic diet. Fasting can induce ketosis.

If you eat three meals a day, snack frequently, and don’t exercise, your body always has a steady stream of glucose. Intermittent fasting extends the periods that your body has burned through the calories of your last meal. Research shows this gives your body more opportunity to burn stored body fat and may protect against chronic disease.

Fasting may provide the following health benefits:

Better gut health. Eating three meals and several snacks is not good for people with digestive problems. Bloating, gas, heartburn and diarrhea can all be made worse by eating all day. Digesting food is hard work for your body. People with an overgrowth of bad gut bugs will be providing those bugs with fuel for fermentation if they eat too often. People who don’t make enough stomach acid, bile or digestive enzymes can all suffer if they eat too often. Leaving a longer amount of time with no food can allow the gut lining to heal if it is leaky or inflamed. Chemotherapy typically causes a leaky gut. Fasting also increases levels of good bugs in the gut. People with inflammatory bowel disease and irritable bowel syndrome usually feel much better while intermittent fasting.

 Less visceral fat. Visceral fat is the deep internal fat that can accumulate in the liver, around the heart, in the pancreas and inside arteries. It is the type of fat that raises the risk of serious diseases. Eating less frequently allows a reduction in the hormone insulin and increase in human growth hormone. These changes allow your body to utilise stored fat more easily. Your metabolic rate goes up and weight loss usually occurs from the torso.

 Reduced insulin resistance and type 2 diabetes risk. Type 2 diabetes is end stage insulin resistance. As mentioned in the point above, a reduction in blood insulin levels occurs when a person eats less often. This means insulin becomes more efficient in the body and better able to control blood sugar.

 Less inflammation and better immune health. Elevations in blood sugar, and burning glucose for energy can increase free radical activity in the body. Free radicals can cause damage to proteins that make up your body, increasing wear and tear and aging your body more rapidly. Stored body fat is a cleaner burning fuel that generates fewer free radicals.

 Improved heart health. Studies have shown that people who practice intermittent or prolonged fasting are likely to see an improvement in their blood pressure, triglycerides, cholesterol and blood sugar. This helps to reduce the risk of heart disease. These improvements are usually due to the reduction in visceral fat levels and reduced insulin resistance.

Please consult with your own doctor before attempting fasting.

Reference: European Society for Medical Oncology (ESMO) Congress 2023: Abstract LBA94. Presented October 20, 2023.

The above statements have not been evaluated by the FDA and are not intended to diagnose, treat or cure any disease.