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Intermittent Fasting: Diet Trend or Scientific Breakthrough?

The best of all medicines is resting and fasting.”

Benjamin Franklin

Here at Cenegenics®, we believe in finding healthy, sustainable approaches to eating. Oftentimes, our approach conflicts with the latest dieting fads which promise unrealistic weight loss results. Yet, every now and then, eating styles emerge which actually align with our principles for dietary wellness. For instance, the Mediterranean diet is a nutrition plan which works well (with several components that work well) for many of our patients. It turns out that the same may also apply for intermittent fasting.

Chances are you may have heard some buzz circulating about this principled approach to eating. Recently, it’s made headlines not only for its ability to promote, but also for the additional health benefits it can provide. So, does intermittent fasting really live up to the hype? Here’s our take on it.

What Is Intermittent Fasting?

image of an abundance of food including meat, garlic, bread, raw veggies, fruit, olives, a pineapple, etc

First and foremost, it’s important to note what intermittent fasting isn’t. Although it’s backed by celebrities and bloggers and may be currently trending, it’s not a fad diet. It doesn’t promote any unrealistic or nutrient-depriving eating patterns; instead, it enforces some sustainable guidelines – namely, the time frames during which you eat versus fast.

In itself, the term “fasting” may conjure up feelings of dread among many people. After all, it seems synonymous with deprivation. Yet, fasting is not starvation, which is extreme food deprivation. Moreover, research suggests that over time, people who practice intermittent fasting actually experience reduced appetites. [1] That’s because intermittent fasting is both attainable and quite possible to sustain over a long-term basis.

In fact, it’s actually quite simple. Followers of this eating style practice daily time-restricted feedings, in which they limit their window during which they consume food. Oftentimes, the eating time is narrowed to six to eight hours per day, while the remaining hours are left for fasting. [2]

With that being said, it’s also possible to start with a wider “eating” window as you get accustomed to the approach. For instance, you might start with an eating window that spans from 8 am to 6 pm. For those just starting out, we recommend starting with a 12-14 hour window and narrowing it down slowly from there. Ideally, there should be ample time between the end of your eating window and your bedtime.

Another approach to intermittent fasting is the 5:2 fasting rule. With this method, you’d eat a single, moderate-sized meal on two days of the week, and resume your normal meal habits on the remaining days. [3] This approach, while effective, may be best reserved for those who have experience with fasting, as it may be difficult to maintain at first.

Of course, limiting the hours of the day during which you eat doesn’t mean you can make poor dietary choices. To truly realize both the weight loss and overall health benefits, you’ll also need to choose quality foods, such as lean protein, healthy fats, plenty of vegetables, and some fruit. These basic principles are all there is to intermittent fasting, however. And, despite its simplicity, the approach can produce impressive results.

How Does Intermittent Fasting Lead to Weight Loss?

A man with a blue apron on in a kitchen cutting up vegetables

One of the reasons intermittent fasting is more than just a fad is because it’s been thoroughly researched and backed by science. Fasting has been practiced by populations across the world for millennia, and it’s even being used (under physicians’ supervision) to prevent and treat diseases in many clinics. [4] And, for good reason. From a scientific standpoint, intermittent fasting leverages our body’s natural mechanisms, allowing us to use our own physiology to drive healthy changes. 

Here’s how it works. When we eat, gut enzymes break down the food we consume, and the nutrients ultimately become molecules in the bloodstream. Carbohydrate-rich foods (in specific, sugars and refined grains) break down into sugar quickly, which the cells can use for energy. If we don’t use all that energy, however, it gets stored as fat. Moreover, sugar can only enter the cells with the help of insulin, a hormone which is produced by the pancreas. [5]


During the time between meals, insulin levels drop and fat cells then release excess sugar for energy. This rapidly accessible sugar fuels the body. As a result, we lose weight and burn off excess fat. The process only works, however, if we truly break between meals – without any snacking. [6] Because most Americans have three meals per day along with snacks and at various times, they don’t experience these periods of food scarcity, known as metabolic switching. [7]

Indeed, weight loss is the most popular reason people change up their standard approach of eating at their “normal” times of day and seek out intermittent fasting. [8] And they’re right to do so. Not only does the fasting window typically impose fewer meals or snacking, leading to an automatic reduction in calories, but it has also been shown to increase metabolic rate, spur weight loss in just a few weeks, and reduce waist circumference, including the harmful abdominal fat associated with increased disease risk. [9] If those benefits alone aren’t compelling enough, however, you might also consider the additional health benefits that intermittent fasting can deliver, below.

What Are the Additional Benefits of Intermittent Fasting?

a heart-shaped bowl with shrimp salad in it and a hand with a watch on the wrist

Aside from driving weight loss, intermittent fasting has also been linked to the following noteworthy benefits.

  • Reduced insulin resistance: In a study of obese men with prediabetes, restricting eating to an eight-hour window led to dramatically lower insulin levels and improved insulin sensitivity.  [10]
  • Improved cardiovascular health: In the same study, the subjects also experienced significantly lower blood pressure. [11] The eating approach has also been linked to decreased risk factors for heart attack and heart disease, including “bad” LDL cholesterol inflammatory markers, and blood triglycerides. [12]
  • Reduced inflammation: Certain research points to reduced markers of inflammation when intermittent fasting is practiced, which is a known factor in the risk for many chronic conditions. It’s also been linked to reduced cancer risk, as well as minimized tissue damage and improved surgical outcomes. [13, 14]
  • Better cognitive performance: Adults who have participated in intermittent fasting studies witnessed improved verbal memories. In animal studies, researchers have observed better associative, spatial, and working memory. [15] The cognitive improvements could result from the release of the brain hormone BDNF, which is triggered by intermittent fasting and promotes nerve cell growth. As a result, it may even help to prevent Alzheimer’s disease. [16]
  • Minimized aging: Intermittent fasting can reduce cellular aging, as well as the risk for some age-related diseases. It has also increased overall lifespan in some animal studies. [17]
  • Improved physical performance: Although fasting spurs weight loss, it specifically targets fat. In studies, men who fasted for 16 hours were able to maintain their muscle mass despite reducing their body weight. [18]

Clearly, there are many compelling reasons to consider intermittent fasting. And, it doesn’t have to be complex, but rather, can be approached with a few simple principles.

How Can You Get Started with Intermittent Fasting?

A man down in a “starting” position as if getting ready to start a race

While there are numerous approaches to intermittent fasting, the best one for you is the one you’ll be able to sustain. Of course, you can always start with a smaller fasting window and larger eating window, and gradually increase the fasting period over time.

As you choose the fasting duration that’s best for you, here are a few simple tips to keep in mind:

  • Stick to the schedule that fits your day. Try to select the time frame that will work best for your day. If you’re an early riser, for example, you may not want to choose a 10 am to 6 pm eating window; a 7 am to 3 pm window could fit better with your lifestyle.
  • Avoid nighttime snacking. No matter which schedule you select, avoid nighttime snacking. As the body prepares for sleep, it’s especially important to break from eating.
  • Steer clear of added sugar and refined grains. Regardless of whether or not intermittent fasting is ultimately for you, these foods are among the least healthy options you can choose. Selecting lean protein, vegetables, healthy fats, fruits, and occasional whole grains will not only improve your intermittent fasting results, but also your overall health.
  • Stay active. Turbocharge your intermittent fasting efforts by staying active throughout the day, which can further help to burn fat between meals.

According to experts, it’s natural to feel hungry and irritable when you first start out. Yet, the body and brain typically catch up to intermittent fasting over time – typically within two weeks to a month. [19] And, once you start seeing the many benefits of this approach, from weight loss to greater mental clarity, you may be even more inclined to stick with it.

The Simplicity of Intermittent Fasting - In Conclusion

a middle-aged man and woman smiling and jogging

For the right populations, intermittent fasting could be a sustainable, effective approach to losing weight, maintaining a healthy weight over a long-term basis, and promoting overall optimal health. It’s a simple yet principled method which can improve insulin sensitivity and unlock a number of key mental and physical benefits, including anti-aging results and better cognitive performance. Unlike fad diets, it doesn’t promote unsustainable habits, severe restriction, or deprivation.

Yet, at Cenegenics® we know that everyone has unique needs. Although we recognize the benefits of intermittent fasting, if it isn’t right for you, we’ll help you find the dietary approach that is. Included in the Cenegenics® cost of membership is a comprehensive, elite health evaluation, which allows our clinicians to uncover any biomarkers that could help shape personalized dietary recommendations for your specific needs. Based on these factors and your unique lifestyle, we’ll come up with an eating plan that works for you and promotes the best version of yourself. See the weight loss and management results our satisfied patients have achieved through our program by taking a look at the Cenegenics® reviews page online.

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Read further for opinions by trusted physician, Dr. Oz. 

Next Steps – Unlock the Benefits of Intermittent Fasting

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About the Contributor

Rudy Inaba 
Global Director of Nutrition & Exercise

Rudy Inaba is Cenegenics’® Global Director of Nutrition & Exercise. He is a recognized fitness and sports nutrition consultant with nearly 15 years of experience in clinical exercise physiology and lifestyle management. After pursuing his Master of Science in Clinical Exercise Physiology at the University of Nevada Las Vegas, Rudy joined Cenegenics where he leads 20 clinical locations nationwide in their advancements in kinesiology, nutritional biochemistry, and their analyses of industry research & market trending.

Key Resources

This guide was produced with contributions from the following key resources: 

The Cenegenics Education and Research Foundation  

The Textbook of Age Management Medicine Volume 1: Mastering Healthy Aging Nutrition, Exercise and Hormone Replacement Therapy

Click to purchase

The Cenegenics Education and Research Foundation  

The Textbook of Age Management Medicine Volume 2: Mastering Healthy Aging Nutrition, Exercise and Hormone Replacement Therapy

Click to purchase

Textbook Authors:

Jeffrey Park Leake, M.D., CPT

Dr. Jeffrey Park Leake is a Partner and Director of Education at Cenegenics Elite Health specializing in age management and wellness. Having trained hundreds of physicians worldwide, Dr. Leake is also the Director of Education for the Clinical Strategies for Healthy Aging course at AMM Educational Foundation.

Todd David Greenberg, M.D., CSCS

Dr. Todd Greenberg is a practicing physician with a broad range of expertise, including wellness, exercise, sports injuries, and MRI of sports injuries. He is a Radiology Clinical Associate Professor at the University of Washington.


[1] Cell Metabolism. Derived from:

[2] Intermittent fasting: Live” fast”, live longer? Derived from:

[3] See above.

[4] Fasting: Molecular Mechanisms and Clinical Applications. Longo, Valter D. and Mattson, Mark P.   Derived from:

[5] Intermittent fasting: Surprising update.  Tello, Monique M.D. Derived from:

[6] See above.

[7] See above.

[8] Fasting for weight loss: an effective strategy or latest dieting trend? Johnstone, A.  Derived from:

[9] A Very Powerful Weight Loss Tool. Derived from:

[10] See above.

[11] See above.

[12] Health Benefits. Derived from:

[13] See above.

[14] Intermittent Fasting: Live “Fast”, Live longer?  Derived from:

[15] See above.

[16] See above.

[17] See above.

[18] See above.

[19] See above.

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