What about intermittent fasting?

Jan 26

Is there any scientific evidence of benefits and are there any risks?

Intermittent fasting (IF) is a health and wellness strategy gaining popularity for its potential benefits in preventing or treating various conditions such as cardiovascular disease, diabetes, cancer, obesity, and dementia.

Intermittent fasting is an eating pattern that alternates between periods of eating and fasting. It doesn't specify which foods to eat, but rather when to eat them. There are several different methods of intermittent fasting, all of which split the day or week into eating periods and fasting periods.

Variations of IF include:

Calorie-Restricted Eating: Reducing daily calorie intake by 15% to 40% and maintaining this reduction over time.
Time-Restricted Feeding: Limiting food intake to a 4- to 12-hour window each day. Most people typically eat for 16 to 17 hours and fast for 7 to 8 hours (or less) during their sleep.
Periodic Fasting: Involves days of significantly reduced calorie intake (around 25% of usual intake) alternating with days of normal eating.

Here's an overview, including recommendations for implementation and reference to relevant research studies.

The research evidence for the health benefits of intermittent fasting and time restricted eating

Research shows that intermittent fasting can have several health benefits. These include weight loss, improved metabolic health, reduced inflammation, improved cell repair processes, and fat burning. It may also benefit heart health, reduce blood sugar levels, and improve insulin resistance. Some studies suggest that intermittent fasting could improve aspects of cardiovascular health, including blood pressure, heart rate, cholesterol, and triglycerides.

These appear to be the key potential benefits:

Improved Brain Health: IF can increase brain-derived neurotrophic factor (BDNF), linked to reducing depression and preventing Alzheimer's disease.

Cancer and Chemotherapy: Fasting cycles have been shown to retard the growth of tumors and sensitize a range of cancer cell types to chemotherapy. A study by Bianchi et al. in 2012 found that fasting cycles can retard tumor growth and increase the effectiveness of chemotherapy in cancer treatments.
Cardiometabolic Health: IF may help in weight loss, improved lipid profiles, lower blood pressure, and increased insulin sensitivity. A study during Ramadan by Cherif et al. explored time-restricted feeding's effects on cognitive performance and exercise, highlighting the benefits of IF in cognitive functions and physical performance.
Longevity: Studies have shown IF can improve longevity in animal models, although human data is less conclusive. Longo and Panda's 2016 research highlights the role of IF in fasting circadian rhythms and its impact on a healthy lifespan.

Are there any risks?

However, intermittent fasting also has potential side effects and risks. Depending on the length of the fasting period, people may experience headaches, lethargy, crankiness, and constipation. Other side effects can include dizziness, nausea, insomnia, and weakness. It's also important to note that skipping meals and severely limiting calories can be dangerous for people with certain conditions, such as diabetes. Some people who take medications for blood pressure or heart disease may also be more prone to problems during longer-than-normal periods of fasting.

It's crucial to discuss the benefits and risks of intermittent fasting with a healthcare professional before starting, especially if you have a medical condition or are currently taking medications. It's also important to monitor for prolonged side effects when practicing intermittent fasting, as this may be a sign that it isn't working for your body.

Recommendations for Implementation

Start Slow: Begin with a mild form of IF, such as extending your overnight fasting period by delaying breakfast or having an early dinner.
Be Mindful of Nutritional Needs: Ensure you're getting all the necessary nutrients in your eating window.
Combine with Exercise: Adding a workout to a 16:8 IF ratio (16 hours fasting, 8 hours eating) can transform your body’s physiology, promoting recovery and regeneration.
Monitor Your Body's Response: Observe how your body reacts to IF. Adjust the duration and frequency of fasting according to your comfort and health goals.
Consult a Healthcare Professional: Before starting an IF regimen, especially if you have existing health conditions, consult a healthcare professional.
Not Suitable for Everyone: Children and adolescents should not practice IF as it can affect their growth and academic performance. Anyone under 21 should approach IF with caution and under medical supervision.

Summary

In conclusion, while intermittent fasting can offer several health benefits, it's not suitable for everyone and can have potential side effects. Intermittent fasting offers a range of health benefits and can be a valuable tool in managing weight, improving metabolic health, and potentially extending lifespan. However, it's crucial to approach IF with a thoughtful plan, considering individual health conditions and nutritional needs. Always seek medical advice before starting any new diet or exercise program, especially if you have pre-existing health conditions or are under the age of 21.

References

https://www.hopkinsmedicine.org/health/wellness-and-prevention/intermittent-fasting-what-is-it-and-how-does-it-work.

https://www.precisionnutrition.com/intermittent-fasting

Vasim I, Majeed CN, DeBoer MD. Intermittent Fasting and Metabolic Health. Nutrients. 2022 Jan 31;14(3):631. doi: 10.3390/nu14030631.

Allaf M, Elghazaly H, Mohamed OG, Fareen MFK, Zaman S, Salmasi AM, Tsilidis K, Dehghan A. Intermittent fasting for the prevention of cardiovascular disease. Cochrane Database Syst Rev. 2021 Jan 29;1(1):CD013496. doi: 10.1002/14651858.CD013496.pub2.

Greg Wells PhD

For Dr. Greg Wells, health and performance, particularly under extreme conditions, are personal and professional obsessions. As a scientist and physiologist, he has dedicated his career to making the science of human limits understandable and actionable. Dr. Wells has spoken to audiences all over the world at events such as TEDx and The Titan Summit, where he has shared the stage with Robin Sharma, Richard Branson, Steve Wozniak and Deepak Chopra.

For over 25 years, Dr. Wells has worked with some of the highest-performing individuals on the planet, including Olympic and World champions, and with organizations ranging from General Electric to BMO, Deloitte, KPMG, BMW, Audi, Sysco Foods, YPO and Air Canada. He is also committed to inspiring children and young adults through his close working relationship with school boards and independent schools.

A veteran endurance athlete, Dr. Wells has participated in the grueling Nanisivik Marathon 600 miles north of the Arctic Circle, Ironman Canada and the Tour D’Afrique, an 11,000 km cycling race that is the longest in the world. He is also a travel and expedition adventurer who has journeyed through every imaginable terrain and conditions in over 50 countries around the world.

Dr. Wells is author of three best-selling books – Superbodies, The Ripple Effect, and The Focus Effect – and hosted the award-winning Superbodies series, which aired on Olympic broadcasts worldwide in 2010 and 2012.

Dr. Wells has a PhD in Physiology, served as an Associate Professor of Kinesiology at the University of Toronto and is an exercise medicine researcher at the Hospital for Sick Children in Toronto.

He is the CEO and founder of The Wells Group, a global consulting firm committed to achieving the moonshot of helping teams, schools and businesses become places where people get healthy, perform optimally and ultimately - reach their potential.

http://www.drgregwells.com