Behind the Hype: The Healthful Advantages of Fasting

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Now that January has come and gone, how are you doing with your New Year’s resolutions? If you’re like the majority of people, you’re already looking at your resolutions in the rear-view mirror—and you’re not too thrilled with the view! (Sorry, I just couldn’t help myself.) I’m sure you’ve noticed the January media feeding frenzy surrounding every possible new diet, fad, and “miraculous scientific breakthrough” that has to do with losing weight and exercising more. And chances are, you’re starting to tune out.

In the midst of the noise touting these myriad fads and fallacies, there’s one well-documented, scientifically validated weight management approach that I hope you won’t reject out of hand. That approach is called Intermittent Fasting (IF), which has rapidly been gaining popularity and scientific endorsement. After spending countless hours studying the science behind it, I now use IF for myself and also apply it very successfully to my coaching clients’ regimens.

My goals in this month’s blog are two-fold: I want you to know that IF is a scientifically sound, safe, and effective approach to weight management and living a longer, healthier life, and I want to encourage you to further educate yourselves about it if you are considering implementing it.

So What is Fasting? Isn’t it the Same as Starving?

Fasting, which is going completely without food for a period of time, is a natural part of our biological heritage. Our bodies evolved to accommodate periods of fasting and feasting. If you think about our ancestors prior to the advent of modern agriculture, they were certainly not eating three meals a day and constantly snacking. Rather, they were killing animals that they needed to consume all at once, and then going days, if not weeks, before finding another primary source of calories. Our bodies evolved to feast, store excess food for fuel, burn up the fuel in the absence of food, and feast again when food became available.

The problem with our current pattern of eating is that we’re rarely giving our bodies a chance to burn off the excess stores of fuel, because we’re eating throughout the day and sometimes even the night. When you factor in that much of the food we consume is processed, containing many unhealthy and even toxic substances, you realize we’re creating a perfect storm, which leads to obesity, Type II Diabetes, and many other chronic diseases.

So how does fasting work? Why not just cut calories instead?

When we eat, the hormone insulin is released, which moves the glucose (sugar) from our food out of the bloodstream and into the liver, where the glucose molecules are strung together in long chains to form glycogen. But the liver has only limited storage capacity for the glycogen. Once the liver is full, it turns the excess glycogen into fat, most of which is then deposited around the body. When you fast, your body will simply draw from those fat deposits for energy. If you start eating soon after you roll out of bed, however, eating breakfast, lunch, dinner and a few snacks, your body has no reason to use your existing fat and you end up gaining weight. To lose weight, you need to increase the amount of time you burn food energy.

The primary problem with just cutting calories as a weight-loss strategy is that your brain slows down the body’s breakdown of food and its transformation into energy (metabolism) to conserve energy and keep your body functioning on fewer calories. In other words, it reduces the number of calories it burns based on the loss of calories consumed. This is why the vast majority of people eventually gain back any weight that they lose even when continuing to consume far fewer calories than before they lost weight. Conversely, fasting unleashes hormones that increase your ability to break down food and transform it into energy. Simply put, fasting causes your body to burn calories faster, while caloric reduction slows down your ability to burn calories.

Fasting contributes to your overall health and weight management in many ways that might surprise you. These include:

  • Improvement in mental clarity and concentration

  • Lowering of blood insulin and glucose, which allows you to burn more fat

  • Increase in energy

  • Reversal of Type II Diabetes

  • Increase in growth hormone, which helps to maintain, build, and repair healthy tissue in the brain and other organs; speeds up healing after an injury; builds muscle mass; boosts metabolism; and burns fat

How long should you fast?

Differing lengths of fasting are effective, spanning the spectrum from fasting for 16 hours with an 8-hour window for eating, to fasting for 2 days per week, to fasting for many weeks at a time. Which pattern you choose will depend upon your reasons for fasting, biology, and lifestyle.

When fasting, you divide eating into two windows. There’s a window of time when you don’t consume anything, other than water, tea, coffee, or broth, and then a window of time when you do eat. Of course, during your eating period, you’re encouraged to eat the “usual suspects”—vegetables, fruits, nuts, legumes, avocados, olives and olive oil, grass-fed meats, wild fish, and organic dairy. Most people who fast don’t find it necessary to count calories, but most do follow low-carbohydrate diets, which augment the fasting process and reduce hunger.

For specific guidelines on fasting, and the reasons behind them, I recommend reading The Complete Guide to Fasting, by Jason Fung, M.D.

Fasting Precautions

  • Don’t fast if you are breast feeding or pregnant.

  • If you’re taking medications, particularly for lowering blood sugar, make sure to consult with a trusted medical professional before embarking on any kind of fasting regimen.

  • Children should not engage in fasting unless they have been directed to do so by a medical professional. However, you might want to think about discouraging your children from snacking continuously, as this may set them up for myriad health conditions such as obesity and Type II Diabetes down the road.

  • If you have ever suffered from an eating disorder such as anorexia or bulimia, please consult with your treating physician, as this may not be the appropriate weight or wellness strategy for you.

Additional resources: (Dr. Berg Interviews Dr. Jason Fung)