On IF

eat less

Freedom is the will to be responsible for ourselves. - Friedrich Nietzsche

Eat less. Yes, eat less. It is simply too easy to over eat in most developed nations. Wake - eat, bored - eat, going to sleep - eat. Continually consuming food, moving as little as possible, and binging on mindless dopamine drips from the meta verse. Startling is the fact that most developed nations are now struggling with obesity issues more so than starvation. What a time to be alive.

It used to be a sign of wealth when one was overweight. It signaled that a person had enough wealth and time to overindulge while many others were malnourished - the elite were obese. This ideology has run rampant the last 75 years, so much so, that the inverse is now true.

The majority of people in developed nations are now obese and it is now a sign of wealth and arguably intelligence to be lithe, fit, and strong. Health is wealth.

So, to signal ones wealth, one is more likely to be fit than fat. Drop the Doritos, hit the rower, and read some Plato. This is what the elites are doing.

What is intermittent fasting? 

Intermittent fasting means something like sometimes one eats, and sometimes one doesn’t. However, when and how much one eats or doesn’t eat varies from one fasting schedule to another. Sounds simple, right? Eat sometimes and don’t eat other times. Unfortunately, the dose is the poison.

  • This essay will include intermittent caloric restriction (such as the 5:2 diet), time restricted feeding (such as the 16:8), and fasting mimicking diets under the intermittent fasting tent.

  • Intermittent fasting offers many benefits. But it doesn’t benefit everyone equally. It can also take some time to acclimate to the new schedule.

In some ways, the concept of intermittent fasting (IF) is so simple it seems ridiculous to read a rather long essay on the subject. Yet, like most things in the health arena, people know what they should do and fail at execution.

  • Fasting” is a highfalutin term for “not eating

  • Intermittent” means “sometimes,” or “occasionally.”

When combined: Sometimes one fasts. Other times one eats. 

Intermittent fasting is simple on the surface, yet it is a bit more complex when one tries to look behind the thing and discern what it actually is.

Questions often arise when learning more about intermittent fasting such as - when should one eat?, how much should one eat?, and how long should one fast for? There aren’t any hard and fast rules that can be applied universally. This essay will cover the topic from many angles and inform one more on how one can implement the principles of IF individually.

Background

Let’s start with some definitions.

  • IF: Intermittent fasting: Occasionally eating nothing

  • IER: Intermittent energy restriction: Eating a lot less (but not zero) on some days, and normally on other days

  • FMD: Fasting mimicking diets: Eating roughly half as much as usual one week of the month

  • ADF: Alternate day fasting: Alternating days of eating with fasting or eating much less

  • TRF: Time restricted feeding: Eating only within a pre-specified period of time, or an “eating window

  • CR: Caloric restriction: Consuming less calories than one expends

IF

Intermittent fasting (IF) is the name some nutrition experts give to the practice of occasionally going for extended periods either eating nothing, or a lot less than usual.

And there are four main ways to do it.

  • Classic IF: Occasionally, one eats nothing. For example, on an Alternate Day Fast, one would fast every other day. Other IF schedules recommend fasting just one or two days a week—or a few (or more days) a month. In buddhist culture a fast akin to this is built in on every full moon.

  • Intermittent energy restriction: Also called “partial fasting,” one consumes less, but not zero. For example, on the 5:2 plan, one would eat normally five days a week and restrict calories two days a week. Often times this is paired with ones workout schedule. Eating more on the days one exercises and scaling back the calories on days one is not exercising.

  • Time-restricted feeding: One confines ones eating to a pre-specified period of time, or an “eating window.” For example, on the 16:8 plan, one consumes food 8 hours a day, fasting for the other 16. On the 20:4 plan, one only eats during 4 hours of the day. Meal skipping also falls into this style of fasting - skipping breakfast and or lunch and only eating dinner is an example.

  • Fasting mimicking diets: For an entire week, one eats roughly half as much as usual. Then for 3-4 weeks, one eats normally, continually repeating the cycle.

Technically, “fasting” is defined as going without food for at least 8 hours. Some of the fasting methods above include 8 hours fasts (or longer)—and some don’t. This is where the term break-fast comes from, historically humans have slept for 8 hours (fasting) and then break their fasts with a morning meal.

For simplicities sake, unless specifically stated, the term IF will be used to encompass all of these eating styles.

History of intermittent fasting

Sometimes intentionally and other times not, humans have gone without food since the beginning of time.

Throughout the world, many tribes have experienced some form of IF, even to this day. They eat a lot when food is plentiful, and much less or nothing at all when food is scarce. Even in industrialized countries, many people still go hungry for economic reasons. Yet, today many people overeat due to a lack of self control and discipline. One is more likely to over-eat than under-eat in most industrialized nations.

Aside from times of scarcity, humans have also fasted on purpose:

  • Ancient Greeks like Plato and Pythagorus sometimes went without food because they believed it lifted health and mental performance.

  • Muslims fast from dawn to sunset during Ramadan. Jews do it on Yom Kippur to atone for their sins. Catholics, too, do a partial fast during the 40 days of Lent by going without a range of foods.

No man is free who cannot control himself. - Pythagoras

It wasn’t until the 1900s, though, that researchers started experimenting with what, how much, and how often they fed their lab mice and rats. Some lucky rodents served as the controls, and had access to food 24-7. Others were much less fortunate. Researchers put them on a strict diet—the kind of diet that most humans would struggle to maintain.

The result: the somewhat starved rodents lived longer.

Over the years, in the name of science, lab rats and mice have eaten just once a day, every other day, or only during certain times of day. These periodic fasts make the rodents healthier: protecting their brains, preventing cancer, and slowing the aging process.

To help humans reap the same benefits, medical professionals began experimenting with a wide range of fasting techniques to promote health, longevity, and weight loss. Eventually, the scientific community figured out that most humans can’t stick with a diet that recommends they stop eating for weeks on end.

So they came up with gentler, more sustainable approaches, such as fasting one or two days a week.

Recent research shows that, when done properly, IF might help:

  • Regulate blood glucose 

  • Control blood lipids such as cholesterol 

  • Reduce the risk of heart disease, cancer, and other diseases

  • Manage body weight 

There’s no single best method

One’s experience with IF can vary widely, because of:

  • physiological differences like age, sex, or health

  • psychological differences such as pain tolerance and will power

  • environmental differences like social support, or living in a food-focused culture

One should test claims, look at the research, understand the basic mechanisms, and adopt a careful, evidence-based approach when constructing a fasting protocol.

How does intermittent fasting work?

Below is a snapshot of what happens in the body when one goes more than 8 hours without food.

  • 0 hours: One eats

  • 0-6 hours: As ones body digests and absorbs the meal, hormones(chemical messengers in the body) and neuropeptides (chemical signals in the brain) are released, helping to move nutrients into cells.

  • 6-8 hours: Most if not all of the meal has been digested. Now one is in what’s called the post-absorptive state. Nutrients from the meal are available for ones cells to use for energy, repair, or other work.

  • 8-12 hours: Ones body has largely cleared and used all the nutrients from the last meal. This shift in energy and nutrient use from “outside sources” (a meal) to “inside sources” (what’s stored in ones body) creates the biochemical changes that define the fasted-state.

  • 12-48 hours: Ones liver releases ketone bodies as well as stored glycogen, and ones liver and kidneys start making glycerol and free fatty acids. These are all substances ones body can use as fuel.

  • 48-72 hours: If one is in the fasted state longer than a couple of days, ones body starts to slow or change key physiological processes in order to stay alive.

  • 72+ hours: By about two to three days into a fast, one is almost completely dependent on fatty acids released from adipose (fat) tissue for fuel. In long-term starvation conditions, this helps spare ones more valuable store of protein, which makes up most important body structures, such as internal organs.

The benefits of fasting largely stem from calorie restriction. When one fasts, one eats less or nothing.

Fasting also stimulates many cellular and molecular mechanisms that our bodies use to thrive in conditions of food scarcity. Blood sugar, insulin, resting heart rate, and blood pressure all decrease—while insulin sensitivity and cell clean out called autophagy improves. Those are all positive signs.

Intermittent fasting and women

While intermittent fasting seems to benefit males, it can have a negative effect on hormones and metabolism in some females. Turns out, the hormones regulating key functions—like ovulation, metabolism, and even mood—are incredibly sensitive to energy intake.

In fact, changing how much—and even when—one eats can alter reproductive hormones. This can lead to a far-reaching ripple effect, causing all sorts of health issues. So, like all other diets and or lifestyle changes one should monitor key health biomarkers an overall wellness to ensure the protocol is worthwhile.

Will intermittent fasting slow metabolism?

One of the biggest objections to the concept of IF is the idea that one should eat frequently to lift metabolism.

A number of years ago, some nutrition experts thought frequent meals would help lift metabolism through something called the thermic effect of food (TEF).

TEF is the energy used to digest, absorb, and utilize the nutrients from food. The theory was that by eating more often, one was stimulating TEF more often. However, TEF is stimulated equally whether one eats three 600 Calorie meals or six 300 Calorie meals.

Man conquers the world by conquering himself - Zeno.

A few terms:

  • Fasting: Going without food long enough (usually 8-48 hours) to trigger the body to dip into stored energy.

  • Starving: A state of extreme nutrient and energy deprivation that can potentially kill us.

One wants to fast long enough to see benefits, but not so long that ones body and brain start to think one is in trouble.

So the question is: How long can one remain in a fasted state? The answer depends on ones individual physiology. For most people, fasting one day a week offers benefits without many risks. It’s the same with 5:2 eating and 16:8 fasting.

24 hours

Hunger hormones are released in waves based on when ones body expects one to eat, which is usually after about five hours of not eating. But if ones deosn’t eat at that time, the wave of hunger will diminish, until the body thinks it’s time to eat again.

Hunger peaks at about five hours after the last meal and immediately diminishes.After a while, even if one hasn’t eaten, one gets less hungry. About 20-24 hours later, hunger comes back again, but to a lesser degree. So, fasting doesn’t generally make one feel as hungry as one might expect. Ones body is highly adaptive and will optimize for myriad conditions.

Fasting works

When it comes to fasting, there’s a sweet spot. Fast too intensely or for too long? One will start to fall apart both mentally and physically. Get it just right, however, and one can experience a wide range of benefits, ranging from improved fat loss to better health.

According to a wide range of studies, IF might alleviate or prevent a number of health conditions, including cancer, type 2 diabetes, and heart disease. IF is a powerful prophylactic that many can leverage for better overall health. IF can also aid in losing fat and lifting brain function. Although IF is a great tool it is not a panacea that fixes all problems.

Intermittent fasting can only lift health so much

It’s not a linear relationship. If one fasts longer and harder, one won’t keep feeling better and better until one is immortal.

But, if one has room to improve, one will probably notice improvements. On the other hand, if one is already doing well, one might not experience much improvement. Possibly because ones metabolic and other health markers are already sound.

Also, consistently restricting energy or nutrients for a long time can actually reverse many IF benefits.

IF might slow aging

None of us can escape aging. But we can age more slowly, and fasting may be a way to do that.

Fasting seems to slow cellular senescence

Senescence is a $10 word that refers to the condition or process of deterioration. When talking about the senescence of a cell, it is when a cell has aged to the point where it can’t divide and regenerate.

When cells senesce:

  • They stop growing and repairing.

  • They resist an honorable and beneficial death called apoptosis.

  • They release pro-inflammatory, tissue-destroying chemicals.

  • They increase protein synthesis (the formation of proteins) and glycolysis (the breakdown of glucose).

  • The ends of their chromosomes—called telomeres—shorten, and they show genetic damage.

Now, to some degree, senescent cells can be useful. For example, they might help suppress tumors or improve immunity. But as one ages and senescent cells accumulate, they start causing problems such as inflammation, chronic diseases, metabolic dysfunction, poor recovery, and most of the unpleasant physical things one associates with aging.

Senescence is inevitable, but malleable. That means one can speed it up, or slow it down.

One can speed it up with things like:

  • Environmental toxins

  • DNA damage

  • Free radicals

  • Chronic and intense stress (which is another reason to focus on the “intermittent” aspect of IF)

  • Some drugs

One might be able to slow it down with IF

A few more terms:

Apoptosis, or programmed cell suicide. Apoptosis is a crucial part of keeping one healthy as one ages.

Other, less drastic forms of cell clean up include:

  • Autophagy: Cells clean up damaged or dysfunctional cellular material and recycle it.

  • Mitophagy: Mitochondrial dysfunction triggers self-digestion.

Interestingly, senescent cells resist these natural cleanup processes. They keep hanging onto life, even though they’re no longer helpful.

Fasting and energy restriction both increase apoptosis, autophagy, and mitophagy.

The potential benefits could show up as decreased inflammation and/or improved longevity.

Fasting may improve cellular signaling

Cellular health and longevity depend on clear and correct chemical communication. When this breaks down, so do cells.

Some of the key signaling pathways that IF potentially affects are:

  • AMP-activated protein kinase (AMPK) signaling: AMPK is an energy sensor that coordinates a large, integrated signaling network that regulates health and longevity. AMPK responds to both low oxygen (hypoxia) and low energy. Activating AMPK (for instance, through fasting) seems to improve lifespan as well as overall health.

  • Antioxidant signaling: Cellular oxidation is a natural part of metabolism, and it’s often likened to rusting. Ones body has its own antioxidant systems to clear the rust, but they slow and break down with age. Fasting may increase the expression of important genes in the antioxidant system and help with overall improved cell signaling.

  • Insulin/insulin-like growth factor-1 (IGF-1) pathway: Insulin and IGF-1 are important for normal growth and anabolism (a crucial factor in muscle gain) throughout the body. But, if these hormones are too high for too long, one has greater risk of diseases related to growth, such as cancer. Down regulating this pathway (or decreasing its activity), as happens in IF, seems to extend lifespan.

IF might improve brain health

IF may slow cognitive decline by:

  • Reducing inflammation

  • Helping to control glucose and insulin

  • Slowing processes of brain cell aging

  • Stimulating neuroplasticity (the brain’s ability to form new synaptic connections)

  • Preserving neurons

IF also shows promise in treating brain diseases and damage, such as after a stroke or concussion, but not all of the research is positive.

Additionally, some report brain fog while fasting, so cognitive performance may not improve during the fasting periods themselves. More research is needed to confirm one way or the other.

IF might reduce risk of type 2 diabetes.

One has much less circulating glucose during fasting, so ones insulin sensitivity (how receptive ones cells are to the action of insulin) and glucose control may improve.

Depending on the fasting type or the health of one doing it, glucose regulation may be only moderately improved, or not at all. Still, for most people who have problems with glucose regulation (aside from people with type 1 diabetes), IF may be one of the safer methods of improving blood sugar control. This is especially true if IF is combined with other healthy habits that can affect glucose regulation, like a high-quality diet, regular exercise, and getting enough sleep.

IF might reduce risk of cancer

Cancers are essentially unregulated, uncontrolled growth, and fasting might impede the development of cancers by:

  • Dampening cellular growth.

  • Cutting down the supply of nutrients and energy.

  • Decreasing growth factors such as IGF-1.

  • Increasing cellular repair and cleanup.

  • Reducing the expression of some oncogenes (cancer genes).

  • Increasing our response to cancer treatment drugs.

Caveat: Fasting alone has not been shown to prevent or cure cancer, but when combined with other approaches, it may help someone stave off disease.

In addition, weight cycling (aka yo-yo dieting) seems to increase cancer risk. This is another reason to attempt IF carefully and moderately, avoiding major ups and downs in body weight and food intake.

IF might improve heart health

IF may protect the heart in several different ways.

C-reactive protein may decline.

The serum level of C-reactive protein (CRP) is a marker of inflammation and risk factor for cardiovascular disease. Some research shows that CRP goes down when one fasts.

Cholesterol and lipid profiles may improve.

Generally, IF seems to improve cholesterol and lipid profile by:

  • Lowering total cholesterol, low-density lipoprotein (LDL, or “bad” cholesterol) and triglycerides.

  • Increasing high-density lipoprotein (HDL, or “good” cholesterol).

The effect, however, seems to be tied to body weight. In people who are already healthy or lean, IF seems to offer less benefit.

Heart rate and blood pressure may decrease

IF seems to lower resting heart rate and improve heart rate variability (HRV), a marker of stress. It also may lower blood pressure, possibly by activating the release of brain chemicals that turn on the calming parasympathetic “rest and digest” branch of ones nervous system.

IF might increase fat loss

IF may help one lose fat more easily through several mechanisms, but the relationship between IF and fat loss is complex.

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Who shouldn’t fast?

There are those who really shouldn’t skip meals, fast for 24 hours, or restrict calories, no matter how much it seems they could benefit from IF.

They include:

  • Those with health issues that necessitate regular meals.

  • Those with a history of disordered eating. Fasting is essentially an eat/don’t eat experience, which is incredibly similar to the binge/restrict cycle.

  • Those who don’t deal all that well with hunger. For example, if they fast or eat less, they end up overeating later.

For these three categories - only eat when hungry

Depending on the intermittent fasting (IF) schedule one follows, ones exercise performance will most likely suffer—at least for a while. One doesn't need to stop working out.

Ramadan

During the holy month of Ramadan, observant Muslims fast every day from sunrise to sunset for about 30 days. The fast-breaking evening meal is often a big dinner.

Over the years, researchers have studied observant Muslims in an effort to find out how fasting affects a range of outcomes, including athletic performance. As it turns out, Muslim athletes tend to do worse in the early weeks of a Ramadan fasting schedule, research finds.

How someone performs depends on several factors: 

  • The individual athlete: Just as some athletes can train harder and longer than others, some also adapt to fasting more easily and more quickly than others. Hello, genetics.

  • Recovery and nutrition: Adequate rest, sleep, hydration, and nutrition can all help the body to adapt more quickly to IF and heavy training.

  • The fasting schedule: Less intense types of fasting (such as the 16:8 protocol) pair better with heavy exercise than more intense styles of fasting.

  • The type of exercise. Fasting is more likely to negatively affect more intense training. (More about this below).

The following activities generally don’t pair well with IF.

  • activities that require intense effort (such as 200-400 meter runs)

  • speed endurance, such as repeated short, intense runs in basketball

  • repeated power-explosive movements like rowing

  • some types of strength and work capacity

One may notice, for example, that one can’t run or cycle up hills like one used to. And if one strength trains, one might not be able to rep out as many push-ups or pull-ups.

Pairing exercise with IF can lift results, too. 

The following activities generally do pair well with IF.

  • Walking or zone 2 training

  • Yoga

  • Pilates

  • Strength training at 60%-70% of 1RM

Low intensity

Our ancestors didn’t kill themselves with tough training sessions. In fact, they wanted to do the opposite: conserve valuable energy and stay limber as long as possible.

Most of their exercise was low effort, such as walking, which goes perfectly with IF. That means:

  • If one is not currently exercising intensely, maintain that status quo when experimenting with IF fasting schedules.

  • If one is currently exercising intensely, consider reducing or eliminating high-intensity training and adding more daily-life type movement instead.

Decrease intensity

What actually counts as too much intensity will vary, but a good general guideline would be:

  • No more than 3-4 hours a week of heavier resistance training

  • No more than 2-3 brief sessions of metabolic conditioning a week  (intervals, high-intensity cardio, circuit training)

  • No more than 1-2 hours a week of moderate intensity cardio (if any)

Meal timing

Most people find they do best when they schedule their workouts on the days they’re better fed. It allows them to have enough energy for workouts as well as nutrients for recovery.

In this regard,the “intermittent” part of IF can work more effectively than a standard caloric deficit.

For instance, if one is cutting calories by 75 percent three days a week and eating normally on the other four, ones workout schedule might look like this:

ENERGY INTAKEACTIVITY TYPE

Day 1 Low
(0 to 25% of normal needs) Low-intensity or active recovery (e.g. gentle yoga, walking, mobility exercises)

Day 2 Normal
(100% of normal energy needs) Higher-intensity or longer duration (e.g. weightlifting, metabolic conditioning, long runs)

Day 3 Low
(0 to 25% of normal needs)Low-intensity or active recovery

Day 4 Normal
(100% of normal energy needs) Higher-intensity or longer duration

Day 5 Low
(0 to 25% of normal needs) Low-intensity or active recovery

Day 6 Normal
(100% of normal energy needs) Higher-intensity or longer duration

Day 7 Normal
(100% of normal energy needs) Higher-intensity or longer duration

In sum

The benefits of IF and its derivatives are apparent. One can follow either a fasting schedule or something that is more malleable to ones current lifestyle. The fact that one is exploring these options is what is most important, the research needed to effectively implement a fasting schedule is imperative to its eventual adherence. Knowledge is power and implementation is godly.

So, whatever schedule one decides to follow the follow through of the schedule selected is vital. Devise a plane, follow through, and unlock better health.