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The ancient Greek doctor Hippocrates (460-370 BC) recommended a program that sounds like Intermittent Fasting plus Ketogenic: ‘Fat people who want to reduce,’ he wrote, ‘should take their exercise on an empty stomach and sit down to food out of breath… Their meat should be fat as the smallest quantity of this is filling. They should take only one meal a day…

There are many references to fasting or (intermittent fasting) through the known ancient world. The Greeks and The Romans all had their practical fasting ideas.

The Greek philosopher Pythagoras who lived nearly 500 years before Christ lived a life of fasting. His followers were actually vegetarians it is written.

The Roman philosopher Seneca is documented as advising his friend Lucilius to “set aside certain days and be content with the scantiest and cheapest fare and endure for three for four days at a time and sometimes more.”

I share this as I knew little about fasting when I started. And I now believe it to be the key part of the puzzle that has helped me change my relationship with food.

What do I mean when I say “Relationship with food?”

Earlier this week I was at a tech conference with my friend Vinny. We were actually talking about fasting of all things. He said, “Fasting worked for me for about three months and then it started to fade off as a way to lose more weight.?

Just about that time, 2:30 pm, the server brought out three plates of fried horderves and Vinny jumped on them because he had been fasting all day. I was able to resist the temptation and my new relationship with food is why. Now I was hungry too, it had been a stressful day at work, and had the server brought out a healthier option I would have eaten. But because the only option was fried, my new relationship with food gave me the willpower to not eat.

Fasting is not new to humans but it is one of the lesser known efficient ways to lose weight and improve health. I think it’s lesser-know because the industry has not figured out how to make billions on it yet. But they will…

Fasting was my key to my weight loss as it empowered me to say “no” when needed.

Three years ago, I would have cleaned all three of the plates in front of me and washed it down with a coke. Back then I was not in control of my relationship with food.

Intermittent Fasting (IF) as a weight loss approach has been around in various forms for centuries, but gained modern relevance in 2012 by BBC broadcast journalist Dr. Michael Mosley’s TV documentary Eat Fast, Live Longer and book The Fast Diet.

Then came Kate Harrison’s book, The 5:2 Diet based on her own experience, and subsequently Dr. Jason Fung’s 2016 bestseller The Obesity Code.

The Backstory on Intermittent Fasting

Dr. Fung successfully combines plenty of research, his clinical experience, and sensible nutrition advice, and also addresses the socioeconomic forces keeping us fat. He is very clear that we should eat more fruits and veggies, fiber, healthy protein, and fats while avoiding sugar, refined grains, processed foods.

Intermittent Fasting can Help Weight Loss

The food we eat is broken down by enzymes in our gut and eventually end up as molecules in the bloodstream. Carbohydrates, particularly sugars and refined grains (think white flours and rice), are quickly broken down into sugar, which our cells use for energy. If our cells don’t use it all, we store it in our fat cells as fat. But sugar can only enter our cells with insulin, a hormone made in the pancreas. Insulin brings sugar into the fat cells and keeps it there.

Between meals, as long as we don’t snack, our insulin levels will go down and our fat cells can then release their stored sugar, to be used as energy. We lose weight if we enable our insulin levels to decrease. The entire idea of IF is to allow insulin levels to decrease enough, and long enough, that we burn off our fat. Simple right?

Intermittent Fasting can be Hard…

New research is suggesting that not all IF approaches are the same, and some are actually very effective, and sustainable, especially when combined with a nutritious plant-based diet. Researchers from the University of Alabama conducted study with a small group of obese men who were pre-diabetic. They compared a form of intermittent fasting called “early time-restricted feeding,” where all meals were fit into an early eight-hour period of the day (7 am to 3 pm),or spread out over 12 hours (between 7 am and 7 pm). Both groups maintained their weight (did not gain or lose) but after five weeks, the eight-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure.

The best part?

The eight-hours group also had significantly decreased appetite. They weren’t starving.

Just changing the timing of meals, by eating earlier in the day and extending the overnight fast, significantly benefited metabolism even in people who didn’t lose a single pound.

Why Might Changing Timing Help?

An in-depth review of the science of IF recently published in New England Journal of Medicine sheds some light. Fasting is evolutionary and embedded within our physiology, triggering several essential cellular functions. Flipping the switch from a FED to FASTING state does more than help us burn calories and lose weight.

Intermittent Fasting for Weight Loss

A recent study concluded that for overweight and obese people, intermittent fasting may be a better approach to weight loss than very-low-calorie diet.

This approach to eating may also benefit metabolism and metabolic health.

There are a few different ways to try intermittent fasting.

Intermittent fasting is a simple, effective approach to fat loss that is relatively easy to stick with.

Studies have shown that when it comes to weight loss, intermittent fasting can be just as effective as traditional calorie restriction, if not more so.

In fact, a 2014 review found that intermittent fasting could help people lose an impressive 3–8% of their body weight in 3–24 weeks

“With good diet and exercise.” Sound familiar?

I think part of Vinny’s challenge was he had assumed he could eat what he wanted when coming off a fast. I don’t subscribe to that theory. For me what I eat and fasting have been fundamentally transforming.

I’m personally more of a Pescatarian than a Flexitarian but due to social events with work find myself recently more of a Flexitarian.

A pescatarian will only eat fish, but as much fish as they’d like, a flexitarian may eat any type of meat, but only on an occasional basis

According to the Center for Disease control in a recent data brief the report that the “prevalence of obesity” increased from 30.5% in 2000 to 42.4% in 2018.

Longevity

A 2016 review found that years of animal studies showed a link between restriction of calories, fewer diseases, and longer life. Scientists have studied the mechanisms behind those benefits and how they could impact us humans.

A 2011 study linked the hormone insulin-like growth factor-1 (IGF-1) to certain diseases that affect lifespan, such as cancer and type 2 diabetes.

Authors of a 2014 study found that eating proteins increases IGF-1 production. Fasting to restrict calories may be a way to decrease IGF-1 levels. This could potentially lower a person’s risk of chronic diseases and extend their lifespan.

A 2011 study linked the hormone insulin-like growth factor-1 (IGF-1) to certain diseases that affect lifespan, such as cancer and type 2 diabetes.

In a recent post regarding plant based diets I shared some longevity information regarding blue zones. A place in the World where people live much longer than the average Human.

Is Intermittent Fasting as Good as it Sounds?

“There is evidence to suggest that the circadian rhythm fasting approach, where meals are restricted to an eight to 10-hour period of the daytime, is effective,” said Dr. Deborah Wexler, Director of the Massachusetts General Hospital Diabetes Center and associate professor at Harvard Medical School.

She recommends we “use an eating approach that works for us and is sustainable.”

I couldn’t agree more and I don’t have an MD or a PhD.

So, here’s the deal. There is evidence suggesting that fasting, when combined with a healthy diet and lifestyle, can be a particularly effective approach to weight loss, especially for people at risk for diabetes. (However, people with advanced diabetes or who are on medications for diabetes, people with a history of eating disorders like anorexia and bulimia, and pregnant or breastfeeding women should not attempt intermittent fasting unless under the close supervision of a physician who can monitor them.)

4 Ways to Better Health

Avoid sugars and refined grains. Instead, eat fruits, vegetables, beans, lentils, whole grains, lean proteins, and healthy fats (a sensible, plant-based, Mediterranean-style diet).
Let your body burn fat between meals. Don’t snack. Be active throughout your day. Build muscle tone.
Consider a simple form of intermittent fasting. Limit the hours of the day when you eat, and for best effect, make it earlier in the day (between 7 am to 3 pm, or even 10 am to 6 pm, but definitely not in the evening before bed). Like Oprah, I Don’t Eat after 8 PM….Just don’t do it.

Avoid snacking or eating at nighttime, Eat with intent..Always with intent.

Considerations

If you’re considering intermittent fasting you should consider if it will fit in your lifestyle. Fasting stresses the body, so it may not be beneficial for you if you are already dealing with significant stress, such as illness. Special occasions and social gatherings commonly revolve around food and drink. Intermittent fasting could impact participation in those activities. But you can navigate that. If you are training for endurance events or you participate in intense exercise you should be aware that intermittent fasting might affect you. Performance if competition or practice falls on fasting day.

“And for the record you can lose weight without exercise. I did.”

Risks

A 2017 review found that although intermittent fasting produced good results in people who were overweight or obese, it could lead to less desirable effects in those who had a lower weight.

These unwanted effects include:

changes in mood
extreme hunger
low energy
obsessive thoughts about food
overeating on days without restricted calories
binge eating behavior
tension
depression
anger
fatigue
confusion

Muscle Loss

There is very limited research on if it is possible to gain muscle during intermittent fasting.

This is likely because weight loss is the topic of interest in most studies.

However, one study on intermittent fasting and weight training provides some information about muscle gain.

In this study, 18 younger men completed an 8-week weight training program. They had not previously been weight training on a regular basis.

The men followed either a normal diet or a time-restricted eating program. The study required them to consume all their food in a 4-hour period on 4 days each week.

By the end of the study, the time-restricted eating group had maintained their lean body mass and increased their strength. However, the normal diet group gained 5 pounds (2.3 kg) of lean mass, while also increasing their strength.

This could mean that intermittent fasting is not best for muscle gain. This may be because the time-restricted eating group consumed less protein than the normal diet group.

There are a few other scientifically based reasons why intermittent fasting may not be optimal for gaining muscle

Benefits

Several studies, although moderate in size, have demonstrated the weight loss benefits of intermittent fasting.

The study’s authors recommend further research before doctors recommend theIF approach for weight loss.

Advocates of intermittent fasting say the following benefits are possible alongside weight loss.

Is Fasting Good for Weight Loss

A recent review concluded that in overweight and obese people, intermittent fasting may be a better approach to weight loss than very-low-calorie diets.

This approach to eating may also benefit your metabolism and metabolic health There are a few different ways to try intermittent fasting.

Intermittent fasting is a simple, effective approach to fat loss that is relatively easy to stick to.

Studies have shown that when it comes to weight loss, intermittent fasting can be just as effective as traditional calorie restriction, if not more.

In fact, a 2014 review found that intermittent fasting could help people lose an impressive 3–8% of their body weight in 3–24 weeks

BUT STOP: Yes science can tell us why or why not. But if you’re like me, a Deplorable, Chained to the desk Monday through Friday guy, what science does not explain is how saying yes or no to food when fasting is key to the management of our relationship with food. It is biological to want to eat when you’re hungry. CHOOSING when to eat and what? That is EMPOWERMENT. That is CONTROL!!! That is a healthy relationship.

Blood Sugar

Some studies have shown that intermittent fasting improves insulin sensitivity more than traditional diets, but other studies have not shown the same advantage.

Researchers have also reported that intermittent fasting and traditional diets lead to comparable decreases in hemoglobin A1c.

More research is necessary to confirm the long-term risks and benefits of intermittent fasting. However, it shows a great deal of promise on a short-term basis.

People with diabetes who take insulin or medication should consult with their doctor before starting a diet, as they must maintain their blood sugar levels.

Failure to maintain correct blood sugar can result in low blood sugar. This may lead to a coma or even death.

Muscle Gain

Exercise, especially weight training can help maintain muscle. A slow and steady rate of weight loss may also help.

Research has shown that you are more likely to lose lean mass, including muscle, when you lose weight quickly

This means that if you are performing intermittent fasting, you not drastically reduce your calorie intake all at once.

While the ideal rate of weight loss may vary, many experts recommend 1–2 pounds (0.45–0.9 kg) per week. However, if preserving muscle is your top priority, you may want to shoot for the lower end of this range.

Intermittent Fasting Increases Fat Burning Hormones

Hormones are chemicals that act as messengers. They travel through your body to coordinate complicated functions such as growth and metabolism.

They also play an important role in the regulation of your weight. This is because they have a strong influence on your appetite, the number of calories you eat and how much fat you store or burn.
Intermittent fasting has been linked to improvements in the balance of some fat burning hormones. This could make it a helpful tool for weight management.

Insulin

Insulin is one of the main hormones involved in fat metabolism. It tells your body to store fat and also stops your body from breaking fat down.

Having chronically high levels of insulin can make it much harder to lose weight. High levels of insulin have also been linked to diseases like obesity, type 2 diabetes, heart disease and cancer

Intermittent fasting has been shown to be just as effective as calorie-restricted diets for In fact, this eating style could reduce fasting insulin levels by 20–31%
See Dr. Berg’s 2-Part Video here to learn more.

Human Growth Hormone

Fasting can cause a rise in blood levels of human growth hormone, an important hormone for promoting fat loss. Some studies have shown that in men, levels of human growth hormone may increase by as much as five-fold while fasting.

This Increases in blood levels of human growth hormone not only promote fat burning, but they also preserve muscle mass and have other benefits.

However, women don’t always experience the same benefits from fasting as men do, and it’s not currently clear if women will see the same rise in human growth hormone.

Norepinephrine

Norepinephrine, a stress hormone that improves alertness and attention, is involved in the “fight or flight” response. It has a variety of other effects on your body, one of which is telling your body’s fat cells to release fatty acids.

Increases in norepinephrine generally lead to larger amounts of fat being available for your body to burn.

Fasting leads to a rise in the amount of norepinephrine in your blood stress.

Types of Fasting

There are several different types of intermittent fasting, such as time-restricted eating, alternate-day fasting, periodic fasting, the 5:2 diet and religious fasting. While they have some common features, the specific programs vary widely.

Time Restricted (Fasting) Eating/Feeding

Time-restricted eating: (also known as time-restricted feeding) restricts all calories to a certain number of hours each day.

This may range from 4–12 hours, but an 8-hour eating period is common.

Alternate-Day Fasting: As the name implies, alternate-day fasting consists of alternating between fasting days and non-fasting days. This means you fast every other day.

While some people eat nothing on the fasting days (true fasting), it is more common to have one small meal on the fasting day (modified fasting).

Periodic Fasting

Periodic fasting (also known as whole-day fasting) consists of occasional fasts, separated by days or weeks of normal eating.

While exact definitions vary, programs involving fasting for one or more days every 1–4 weeks are often considered periodic fasting.

The 5:2 Diet

The popular 5:2 diet is very similar to alternate-day and periodic fasting.

It involves eating normally for five days per week and eating about 25% of your normal amount of calories two days per week

The very low-calorie days could be considered a form of modified fasting, particularly if you only consume one meal.
The 16:8 diet is another option. Eat for about 8 hours and fast for the remainder. Not eating for 16 hours may seem like a lot but if you start at 11am and end at 7 pm it’s fairly easy. This is where I started.I’m not a breakfast person really so it was the most practical place for me to start after I got my coffee routine to all black. See my thoughts on coffee and fasting here.

Alternate Day Fasting

Alternate-day fasting (ADF) is an intermittent fasting approach.

The basic idea is that you fast on one day and then eat what you want the next day.

This way you only need to restrict what you eat half of the time.

On fasting days, you’re allowed to drink as many calorie-free beverages as you like. Examples include:

water
unsweetened coffee
Tea

If you’re following a modified ADF approach, you’re also allowed to eat about 500 calories on fasting days, or 20–25% of your energy requirements

The most popular version of this diet is called “The Every Other Day Diet” by Dr. Krista Varady, who has conducted most of the studies on ADF.

The health and weight loss benefits seem to be the same regardless of whether the fasting-day calories are consumed at lunch or dinner, or as small meals throughout the day.

Studies show that many people find alternate-day fasting much easier to stick to than traditional, everyday calorie restriction

Most of the studies on alternate-day fasting used the modified version, with 500 calories on fasting days. This is considered much more sustainable than doing full fasts on fasting days, but it’s just as effective.

In this article, the terms “alternate-day fasting” or “ADF” generally apply to the modified approach with about 500 calories on fasting days.

Common Questions

Can I still exercise?

In her interview with The Atlantic, Dr. Krista Varady, Professor, Kinesiology and Nutrition, talks about exercise in people following the every-other-day-diet.

After the first 10 days, their activity levels were similar to people following a traditional diet or an unrestricted eating plan. It may be most beneficial for exercise sessions to end 1 hour before mealtime.

Can I drink alcohol?

Here is the simple truth, your body has a priority system when dealing with fuel sources, and near the top of the list is alcohol. If you have alcohol in your body, it will be burned first, before fat.

Also, if you have a big night of drinking and then you go to sleep, your night-time Growth Hormone (GH) levels will be significantly lower than if you had not been drinking.

Why? Because GH is primarily responsible for releasing fat from your body fat stores. This is a big part of how you lose fat at night, according to Brad Pilon, author of Eat Stop Eat.

Won’t I eat too much on feast days?

According to Dr. Varady, people do eat more than their calorie needs on feast days.

However, they do not eat enough to make up the deficit from fast days. Other researchers report that people unintentionally eat less on non-fasting days as well.

Will I be hungry on fasting days?

Dr. Varady reports that the first 10 days on the every-other-day diet are the most challenging.

Calorie-free beverages, such as unsweetened tea, may help offset hunger.

Do I still fast once I’m ready to maintain my weight?

Some plans, such as the every-other-day diet, also include a weight maintenance phase, which involves increasing the number of calories on fasting days from 500 to 1,000.

Other plans recommend decreasing the number of fasting days each week.

If a person has specific conditions or health requirements, it may benefit them to seek consultation with a doctor or dietitian before starting a restrictive diet.

Most people report these feelings and behaviors in the first few weeks of intermittent fasting.

The same review also highlights that restricting calories in this way may interfere with the female menstrual cycle.

I have personally found that knowing how to fast and having the ability to fast or not fast now has really enabled me to have more control than ever.

My suggestion is get your coffee or tea to black with no sweetner. If that does not work for you get to water with lemon. This is important because this is a mini-win you can build on.

Once you’re coffee and tea are black, then go to 16:8 on your meals. Then slowly move to 17:7, 18:4, etc.

Trust me your brain will not like it but once you do this several times you’ll find it’s easier and easier.

If you can eat at your desk even better.

Most days I get to 3:30 fairly easily if I want. Then it comes down to if I want to eat or not.

I like a small snack at this point as it keeps me from acting like the Cookie Monster when I get home.

The Bottom Line

Intermittent fasting is a popular dietary strategy that uses fasting periods longer than a typical overnight fast.

There are several different types of intermittent fasting, including time-restricted eating, alternate-day fasting, periodic fasting, the 5:2 diet and religious fasting.

Intermittent fasting probably does not cause more muscle loss than other weight loss diets.

Nevertheless, adding exercise — especially weight training — to your intermittent fasting program can help you maintain muscle.

Seneca said it best, “set aside certain days and be content with the scantiest and cheapest fare and endure for three for four days at a time and sometimes more.”

Sources

Effects of intermittent fasting on health, aging, and disease. de Cabo R, Mattonson MP. New England Journal of Medicine, December 2019.Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Internal Medicine, May 2017.

FASTING: Crack the Code