Intermittent Fasting for Weight Loss. Updates from IFM’s Annual Conference 2020.

Is intermittent fasting a good approach for weight loss? For many, there is nothing more difficult then taking off weight once it has accumulated. Partially because there is nothing more confusing than finding which diet is right for one for you. One problem is that every “expert" has a different opinion and they are usually very passionate about that opinion. Keto, Vegan, Paleo, Mediterranean, Carnivore, Atkins, Low Carb, High Protein, High Fat, Low Fat, Nutritarian, and the list goes on… The good news about intermittent fasting is that it doesn’t matter if you are keto, vegan, or anything else you can incorporate intermittent fasting in your lifestyle. 

Since I began my Functional Medicine training I have learned about Intermittent Fasting and its benefits, which include;

• Decrease in Insulin Levels (improving glucose control, improving Diabetes)

• Decreased Blood Pressure

• Decreased Heart Rate 

• Weight Loss

• Increase in Testosterone (Helps to turn fat into muscle, stronger bones, better memory, spatial, better libido, improves mood.)

• Increases Human Growth Hormone (Helps to regulate body composition, muscle and bone growth, sugar and fat metabolism, and possibly heart function)

• Increased efficacy of Endurance Training

• Improves Cellular Repair (Removes waste from cells)

• Improves Gene Expression (Just because you have a gene does not mean you are expressing it, but intermittent fasting can help you turn on your good genes and turn off your bad genes)

• Increases your Metabolic Rate (helping you burn even more calories)

• Less muscle loss than continuous calorie restriction

• Decrease Inflammation by Enhancing the Body’s Resistance to Oxidative Stress (When your body can react better to its stressors stemming from your food, gut, hormones, toxins, and mental, emotional, spiritual health your symptoms should decrease. The real key is to identify these underlying causes through the Functional Medicine process. But in the meantime fasting can make you more resilient)

• Increases in Brain Derived Neurotrophic Factor (BDNF) (Studies have shown, the higher you BDNF the lower your risk for Dementia)

• Memory Improvement 

Thats not bad right? So why isn’t everyone doing it? Well, it’s not easy to do. In my clinical experience, patients who came to me already on an intermittent fasting schedule or patients who I recommended to start an intermittent fasting protocol, I didn’t see many ground breaking results, the way I see when working with food sensitivities, gut health, hormones, or detox. I never met anyone who said intermittent fasting changed their life, it was too difficult without the benefits to show for it. Weight loss was minimal. The most common regimen I have recommended or seen is 16 hour fasts starting at 3 times per week. A 16 hour fast means that if dinner is at 6pm then your next meal should be at 10am the next day.

During our most recent Annual International Functional Medicine conference in June 2020, I saw a physician named Dr. Jason Fung M.D. present information about longer fasting periods. He presented studies where patients fast for 24-36 hours, 2-3x per week. That means if dinner is at 6pm, then your next meal is not until 6pm the next day or 6am 2 days later. 

Why have I not seen dramatic results from 16 hour fasts? Might 16 hours not be enough? 

In the “normal” metabolic process, after eating the body turns glucose into energy and stores whatever is excess as glycogen. (In the United States we tend to eat more than our body requires for energy production so we store quite a bit). Once your body has used the food you gave it and you don’t eat anything new, your body will turn to other sources to make energy, including a process called gluconeogensis, which is when your body uses excess sugar, protein, or fat as fuel.

Gluconeogenesis starts after about 8 hours of not eating, but it takes a little longer to ramp up. This is where I made my error in only recommending a 16 hour fast, the longer you wait before eating again the more effective intermittent fasting is. Estimates are that 54% of glucose (what we use to make energy) comes from gluconeogenesis after 14 hours of starvation, and this contribution raises to 64% after 22 hours and up to 84% after 42 hours. So we need to wait longer to eat.

One of the main reasons I was hesitant to recommend not eating for days at a time, is that it is not easy! Its not a common way of eating in our society and can present many challenges. However the science backs up the method and I believe it is something worth while to try.

If fasting is something you want to try here are some starting points, but always remember, listen to your body, go slow. 

• Start with 12 hours daily. Dinner 6pm, next meal at 6am the following day. 

• Then try adding in 16 hours a 3-7 times a week, while maintaining 12 hours on the other days. Dinner 6pm, breakfast 10am the following day. 

• Within a few weeks you can try 20 to 24 hours, and then 36 hours. Dinner at 6pm, next meal at 6pm the following day. 

• 36 hours mean dinner at 6pm, next meal 2 days later at 6am. 

• The end goal is 2-3 periods of 24-36 hours of fasting every week. 

The longer you practice these principles, the more your body will adapt to your new way of life and the easier it will become. And the best part is, you can stay on whichever diet you are already on. 

* Common side effects you may experience include hunger, irritable mood, and concentration difficulties while fasting. However, that these side effects usually disappear within a month. Drink lots of water and you can have appetite suppressants like green tea or black coffee while you are not eating.

References

https://www.nejm.org/doi/full/10.1056/NEJMra1905136

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050641/pdf/nihms-593309.pdf

https://www.ncbi.nlm.nih.gov/books/NBK544346/

https://pubmed.ncbi.nlm.nih.gov/3127426/

https://pubmed.ncbi.nlm.nih.gov/27569118/

https://pubmed.ncbi.nlm.nih.gov/27810402/

* The information in this article is not intended to replace any recommendations or relationship with your physician.  Please review references sited at end of article for scientific support of any claims made.