Integrative Insights on Fasting Approaches During Chemotherapy
This is a very hot topic in integrative oncology and a question that has come up in practice quite a bit recently. And, cancer or no cancer, the dietary trend toward intermittent fasting (IF) or time-restricted eating (TRE) is on the rise. But that doesn’t mean it’s the right dietary approach for everyone—especially in cancer management.
Before we dive into the specifics, let’s break down a few key details.
What is Intermittent Fasting (IF)?
Contrary to popular belief, intermittent fasting (IF) is an umbrella term that encompasses three main dietary strategies. The term represents a structured approach to short-term caloric restriction, characterized by alternating cycles of eating and fasting periods. Protocols and intervals vary, but common practice is to abstain periodically from eating food longer than the normal overnight fast. The three most common forms of IF include:
Alternate-day fasting (ADF): A 24-hour period of eating followed by a 24-hour fast, repeat.
This specific form of IF involves alternating between days of normal eating and days of fasting or severe calorie restriction. In this fasting approach, individuals cycle between "fasting days" where they significantly reduce their calorie intake or completely abstain from consuming calories, and "feasting days" where individuals consume their usual calorie intake in a balanced diet with regular meals and snacks. This can also be done as a 5:2 diet, where individuals eat normally for five days of the week and restrict calories on two non-consecutive days.
Whole-day fasting: Fasting for a 24-hour period.
Also known as extended fasting or 24-hour fasting, where individuals abstain from consuming calories for a full 24-hour period. This approach involves not eating any food or calorie-containing beverages during the fasting window, which typically spans from dinner on one day to dinner on the next day, effectively skipping one full day of eating. Hydration is encouraged during the fast by consuming non-caloric fluids like water, herbal tea, black coffee, and plain electrolyte drinks. It's also crucial to ensure that the meal used to break the fast provides adequate nutrition like protein, healthy fats, carbohydrates, and a variety of vitamins and minerals to prevent nutrient deficiencies.
Time-restricted eating (TRE): Consuming all calories in an 8-12-hour window.
The primary emphasis of TRE is when you eat rather than what you eat. Individuals consume all their meals and calories within a designated window, typically within 8-12 hours, while fasting for the remaining hours of the day. For example, if you start eating your first meal at 10:00 AM, you would conclude your eating for the day by 6:00 PM (8-hour window) or 10:00 PM (12-hour window).
Benefits of Intermittent Fasting: Autophagy in Cancer and Chemotherapy
As you can see, intermittent fasting intervals come in all shapes and sizes, with each variation prompting different metabolic shifts that may influence cancer treatment outcomes. The Journal of Restorative Medicine published by the Association for the Advancement of Restorative Medicine (AARM) states you can further enhance the benefits of IF by aligning intervals and feeding times with natural circadian rhythms and daily activities. To understand circadian rhythm and how it can be used to optimize health, check out our blog on cancer-related fatigue.
One of the benefits IF is well known for is weight loss. Better metabolic health from IF strategies like time-restricted eating can be beneficial for cancer patients by reducing insulin resistance, but weight loss is NEVER a dietary goal during cancer treatment. Always closely manage your weight loss goals with your oncology team.
This blog post focuses on the additional health benefits of IF including the promotion of anti-inflammatory responses, cardioprotective effects, reduction of oxidative stress, and promotion of (wait for it….) autophagy!
Autophagy is a cellular process where cells "clean up" by breaking down and recycling damaged or unnecessary components. It's like a cell's self-cleaning system. A cell can engulf and digest its own structures, such as old organelles or misfolded proteins, to generate energy and maintain health. Autophagy helps cells adapt to stress, supports proper development, and plays a role in preventing diseases like cancer and neurodegenerative disorders. It's a fundamental process that helps cells function optimally and respond to changes in their environment. The effects of fasting and autophagy are still under study, but many researchers propose that IF could help with the treatment and eradication of tumors and cancer cells and help protect healthy cells from chemotherapy-induced damage.
The Research: Intermittent Fasting and Chemotherapy
Incorporating IF during chemotherapy has shown promise. Studies suggest that fasting can safeguard normal cells from chemotherapy-induced toxicity, while potentially sensitizing cancer cells to treatment. In addition, IF may mitigate chemotherapy's adverse effects, with a reduction in symptoms like fatigue, weakness, nausea, and digestive discomfort.
The Journal of Restorative Medicine identifies the interaction between IF with breast cancer cells and the chemotherapy drug cyclophosphamide (CP). When fasting was combined with CP, tumor size was significantly reduced compared to CP treatment alone. This suggests fasting can enhance the effectiveness of chemotherapy. Fasting can also help reduce tumor glucose consumption thus enhancing the impact of chemotherapy.
The interplay between IF, chemotherapy, and autophagy is intricate. Ongoing research is working to unravel its multifaceted impacts. By embracing an integrative approach that harnesses the synergy between IF and conventional cancer therapies, patients and healthcare practitioners can strive for comprehensive care that targets not only cancer cells but also the overall well-being of individuals navigating the challenges of cancer treatment.
Now, let’s discuss what Chinese medicine has to say about intermittent fasting.
Traditional Chinese Medicine Insights on Intermittent Fasting
Once again, Traditional Chinese Medicine (TCM) has been ahead of the game by suggesting for thousands of years that syncing our eating habits with our internal body clock is key to wellness. This follows the advice of eating with your circadian rhythm where you consume meals during daylight hours and allow the digestive organs to rest at night.
This advice is based on the TCM meridian clock, which maps organ strength at different times. The main digestive organs, the Spleen and Stomach, are strongest and most active in the morning from 7-11 a.m. These organs are responsible for converting what we eat and drink into valuable Qi (energy) and blood and do so most efficiently in the morning. Likewise, fasting before 7:00 a.m. when the Large Intestine is at its peak strength can facilitate its cleansing function. Fasting in the evening between 1-3 a.m. when the Liver is strongest can aid its detoxification role and promote better Qi flow throughout the body.
TCM recommends not eating for 2-3 hours before bed. During the evening and nighttime hours, Qi is naturally moving inwards to organs such as the Liver and Gallbladder and focusing on the restoration and replenishment of organs. The digestive system is believed to be less active during these hours, so eating heavy meals at night can actually weaken our digestive system and take focus away from the body’s rejuvenating process. Furthermore, resting the digestive system at night can help avoid stagnation of food and fluid preventing dampness and phlegm accumulation, imbalances that can lead to various health issues.
In essence, TCM suggests that intermittent fasting can be in harmony with circadian cycles, but rather than skipping meals entirely (as in whole-day fasting), it encourages quality over quantity and mindful adjustments to meal sizes and timings. Inconsistency of eating impairs the body’s ability to make energy, healthy blood, and ensure optimal gastrointestinal health.
Reasons NOT to Follow a Circadian Rhythm Diet
In Traditional Chinese Medicine, individuals may have various reasons for not adhering to a circadian diet due to factors such as their unique constitutional makeup and health conditions. TCM practitioners consider factors such as each person’s balance of Yin and Yang, Qi deficiency or excess, and the specific imbalances of organs when providing dietary recommendations.
Practitioners should also assess the specific nature of a health issue and which internal factors are present, such as excess heat, dampness, or deficiencies in particular organ systems. In some cases, specific dietary modifications may be recommended to address the root cause(s) of a condition. Additionally, modern lifestyles, irregular work schedules, and seasonal variations may make strict adherence to a circadian diet challenging. TCM practitioners will also take into account individual preferences, cultural practices, and dietary restrictions while considering the holistic balance of the body, mind, and environment.
So, the moral of the story is “Eat breakfast like a king, lunch like a prince, and dinner like a pauper” and remember there is no one-size-fits-all diet, especially in the realm of intermittent fasting. What is appropriate for you, may not be appropriate for another cancer patient.
Always seek out advice from your medical providers. If you are curious if fasting is appropriate for you, consider signing up for the Insight Cancer Care 1:1 cancer wellness program, including customized nutrition plans and cancer-specific resources and recipes. For a short write-up on fasting during chemotherapy, click here to request access to my 4-Week Formula program resource.
Contact our office for more information or to book a free consultation with Dr. Bianca!