Intermittent Fasting and the Keto Diet
Some people on the keto diet intermittently fast, fueling their ketosis even more. Because someone on the keto diet is always in ketosis, intermittent fasting will allow him or her to go more deeply into the process and reap even more benefits than the high-carb dieter.
As you fast on the keto diet, your body has to use its stores of fat, rather than what you just ate, to fuel itself, which will help you lose even more weight and fat faster than when you eat three times a day on the keto diet. A recent study showed that combining a low-carbohydrate diet and intermittent fasting caused increased weight loss and improved insulin levels, compared to calorie restriction alone. The keto diet may enhance autophagy; not only is it promoted by fasting but it’s also induced by restricting carbohydrates, suggesting that keto dieters gain more benefits from intermittent fasting than someone on a high-carb diet.
Combining the keto diet and intermittent fasting can take you to the next level of your weight loss journey. It also may help keep you healthier as you live longer by combining the benefits of ketones with autophagy, the body’s smart way of healing itself.
When to intermittent fast
If you’re going to do intermittent fasting, think through your family’s typical eating schedule and how your feeding window will match up with that. Let’s say, for example, that you’ve got to make breakfast for your family and get your kids off to school, but your feeding window is from 12 p.m. to 8 p.m. By the time breakfast rolls around, you may not have eaten for 12 hours, and you’ve got another four to go before you can do anything about it — and now you’re making pancakes.
Consider shifting your feeding window to an earlier time. Feel free to play around with it. There are no hard and fast rules to intermittent fasting — they’re more just guidelines, and you can customize every aspect of it to your specific situation. Because you can have coffee and tea, you might consider having a large cup before you start cooking because these drinks can take the edge off your hunger.
If you’re someone who doesn’t like breakfast anyway, this might be a non-issue. However, at some point, you’re going to run into situations where intermittent fasting just doesn’t line up well with your life, and going through this exercise is very useful.
Most people think of intermittent fasting as a tool to help you lose weight, but if you’re smart about your options, you can intermittently fast and still gain muscle, because there are many ways to fast. If fasting isn’t for you, eating more frequently — whether in a specific eating window or throughout the day — can help you increase your weight gains as well.
This is the time to get clear on your goals and think realistically about how — or if — you want to change your weight when you begin keto. Don’t get too caught up on a specific deadline to achieve your weight goals. It’s crucial to remember that keto is a lifestyle, not a trendy diet, and its best to go in with a long-term view for your weight journey.
Still, it’s best to calculate the number of calories you’ll need to eat to reach your weight goals and compare that honestly with how many calories you currently eat. Figuring out the difference between the two will help you develop a plan of attack to make the numbers align in a way that works for you. Incorporating exercise and possibly fasting will help you achieve these goals in a more dynamic fashion that fits your lifestyle.
When you get into the swing of keto, you’ll likely find that your body naturally moves toward a healthy weight without too much effort.
Keto is an excellent tool to help you reach your healthy dream weight. You’ll need to get clear on how much weight you want to gain or lose and come up with a realistic plan that looks at your calories, macros, exercise level, and meal frequency to get you to your goal.
Benefits of intermittent fasting
You’ve probably heard of intermittent fasting as a common practice for celebrities who need a drastic makeover before their next movie. Fasting is not only excellent for fat loss and muscle gains, but it also has a wide range of other health benefits.
Scientists are discovering tons of benefits to intermittent fasting. Although the discoveries are new, we as a species have been doing it for millennia. Researchers are just finally catching up to what we’ve naturally been doing and identifying that it’s a good idea to go back to ancient ways of eating.
Ketosis and intermittent fasting are the perfect marriage of healthy nutrition, and intermittent fasting may take your keto to the next level.
Accelerating fat loss
Ketosis helps with fat loss by transforming your body into a fat-burning machine. Adding intermittent fasting to ketosis will accelerate fat loss. No matter where you start off, if you stop eating for long enough, your body will stop burning glucose and instead switch to the more efficient fat and ketone burning associated with ketosis and long periods of abstinence from food. This is so important because of insulin, which regulates blood sugar levels. When you fast, you increase your sensitivity to insulin, those hormone levels drop, and you’re less likely to do what high insulin tells your body to do: Burn glucose and store fat.
When carbs (and, therefore, insulin to a large degree) is out of the picture, as is the case with fasting, your body can burn fat, rather than store it. Most important, you can keep it off. The keto diet helps to decrease overall insulin levels, but even keto-approved food (the small number of carbs and the protein) will cause a slight increase in insulin levels after you eat. Fasting does away with that because food is what triggers insulin levels to rise. When you fast, your insulin levels drop, and this triggers your body to burn fat for a more extended period.
Many of these changes are likely maintained by a “fasting hormone,” adiponectin. Adiponectin is increased with calorie restriction, fasting, and weight loss, even though — surprisingly — it’s made by fat cells. Adiponectin has a host of beneficial effects that may explain some of the advantages of intermittent fasting. Higher adiponectin levels are associated with weight loss, whereas low levels are found in individuals who struggle with insulin resistance and type 2 diabetes. In fact, one of the medicines used to treat type 2 diabetes works to increase the levels of adiponectin in the body.
Although both fasting and keto help reduce insulin levels, fasting accentuates keto. When you eat a keto diet, you’re providing fat for your body to burn, and it will burn fat from food before it turns to stored body fat. When you burn through the food you’ve eaten, however, your digestive system begins to work off of stored fat. The longer your fasting period lasts, the more time you’re giving yourself to work through stored fat. The human body can have tens of thousands of calories stored as fat, and if you want your body to use those calories, intermittent periods of fasting are a proven way to achieve your goal.
Despite what many people think, fasting can actually help peak your metabolism. Prolonged starvation may do the opposite, but over the short term of a fast (several days), the body’s level of adrenaline (or epinephrine) goes up. Adrenaline is part of the fight-or-flight system. You don’t want adrenaline to be chronically elevated, but in the short term it can be highly beneficial. Short bursts of adrenaline lead to increased energy use, even when you’re fasting. Adrenaline increases the release of any stored glucose you have available and enhances your ability to burn fat. Studies show that during a short, four-day fast, basal metabolism can increase by up to 12 percent, which can fuel weight loss.
Boosting muscle gain and human growth hormone
Human growth hormone (HGH) causes development and growth in children and teenagers. Of course, it’s normal during this time in anyone’s life to increase muscle mass naturally. Unfortunately, HGH tends to drop after you reach the end of your teenage years, and it never quite picks up again. HGH levels are almost twice as high in children and teenagers as they are in adults. HGH is a pulsatile hormone, meaning that its levels spike and decline. HGH has multiple effects:
- Increases muscle mass
- Increases bone strength and growth
- Breaks down fat
- Increases protein synthesis
- Increases gluconeogenesis in the liver
- Increases growth of all the organs (apart from the brain)
Studies show that providing shots of HGH to both men and women increased muscle mass and bone density while decreasing fat. HGH has been popular as a doping agent in elite sports, and some athletes have used it since the 1980s to improve their athletic abilities. Sadly, injecting HGH comes with a list of side effects like high blood sugar and risk for some cancers and heart issues. Luckily, fasting provides a natural burst of HGH without any of its nagging side effects. Eating suppresses HGH and overeating — or snacking — makes it plummet.
Boosting muscle by cleaning house
Another way fasting improves muscle mass is by accentuating the cell’s ability to regulate its daily cleaning cycle. Similar to your computer’s virus system, your cells are continually monitoring their surroundings for any defects and will repair any abnormal processes. There are two systems that your cells use to do this:
- Autophagy lysosome: This is literally “self-eating” and is the process of gobbling up long-lived (and often abnormal) proteins, RNA molecules, and cellular parts such as the mitochondria, which is the “powerhouse” of the cell. A specific type of autophagy, called macroautophagy, helps reduce metabolic and oxidative stress and is vital for the ability of proteins and other cell parts to be recycled for energy.
- Ubiquitin proteasome: This is the principal mechanism for breaking down and recycling short-lived protein in all your cells. This system is vital for making sure your immune system is functioning, as well as repairing your DNA, the set of blueprints that encodes life. If this system is abnormal, it can lead to a host of diseases like neuromuscular degeneration and immune problems.
These pathways work together to repair your bodies’ cells. Cells are complex, with multiple moving parts, like proteins and mitochondria that power each cell and serve as messengers to carry out essential functions. Whenever a part malfunctions, it must be repaired so the whole cell doesn’t suffer. If either pathway is blocked, the cell becomes damaged, ultimately leading to cell death or destruction.
In muscle cells, this can lead to muscle weakness and wasting. Because muscles are highly active, lengthening and contracting many times a minute, they can easily get worn out if the tools to monitor or repair them are damaged. Besides, maintaining muscle requires a delicate balance of muscle protein synthesis (the scientific term for how muscles grow) and muscle breakdown. These pathways are stimulated by fasting and are a vital part of the body’s ability to maintain muscle function.
Exciting new research shows that autophagy is necessary to maintain muscle mass, and without it, you’re likely to lose the muscle you’ve worked hard to achieve slowly. Studies of animals stripped of the autophagy-promoting gene developed muscular dystrophy — a disease in which the muscles shrink over time, becoming progressively weaker, and eventually leading to difficulty walking, standing, and doing all the routine activities of daily life.
Your muscles won’t necessarily disappear if you don’t start fasting, but this research suggests that if you don’t boost autophagy — effectively accomplished by fasting — you risk increasing muscle loss, setting you up for negative consequences, such as increased likelihood of disability and a loss of independence.
Intermittent fasting has often been popularized by highly trained athletes, who prioritize a sculpted and lean physique. It would be surprising if they continued to fast if they lost muscle mass or saw a decrease in their performance. Their results indicate that fasting works for a lot of people.
Accelerating recovery and repair
Fasting helps to keep the body in good working order. Fasting can improve your body’s function by
- Decreasing oxidative damage to the body’s proteins
- Decreasing oxidative damage to DNA
- Decreasing the accumulation of dysfunctional proteins and parts of cells
Fasting not only affects insulin and glucose levels, but also exerts a significant effect on a closely related hormone, insulin-like growth factor 1 (IGF-1). IGF-1 is stimulated by HGH and causes most of the adverse effects of excess HGH, like high blood sugar and the risk of cancers. IGF-1 is mostly made by the liver and helps promote the growth of almost all the cells in both children and adults, from muscles to bones.
Excess IGF-1 is tightly linked to an increased risk of cancers, a condition characterized by the inability of the body to regulate and repair abnormal cells. There are multiple checkpoints throughout a cell’s life that allow for evaluation, repair, and even the death of cells that have lost function — or worse, are becoming abnormal or cancerous. IGF-1 decreases the body’s ability to manage these abnormal cells. Interestingly enough, people with IGF-1 deficiency are extremely unlikely to get cancer. Research shows that the blood from people with IGF-1 deficiency may protect cells from undergoing oxidative DNA damage. And even if some cells became damaged, the IGF-1 blood helped to make sure the cells were destroyed or discarded so they wouldn’t grow to form cancer.
More research is needed, but small studies show that people who fast while taking advanced medication for cancer, such as chemotherapy, may do better than people who merely receive the chemotherapy. Not only do the people on fasts notice fewer side effects from chemotherapy — of which there are many — but studies show that in mice, intermittent fasting can decrease the risk of blood cancers and may be just as effective as chemotherapy for certain types of cancers.
Interestingly, fasting-induced autophagy is inhibited by mammalian target of rapamycin (mTOR), one of the common complexes that are upregulated during cancer and one of the primary targets for cancer drugs. This is more proof that natural ways to boost autophagy may help reduce our risk of cancer, or even treating it after it has formed. In addition to decreasing the risk of neurodegenerative disorders like Alzheimer’s, fasting-induced autophagy helps limit inflammation throughout the body, which is also useful for reducing susceptibility to cancer (because many cancers are thought to be related to increased inflammation).
Improving skin tone
Clear skin may not be the first benefit you think of when fasting is mentioned, but it can be a particularly enticing bonus. Similar to keto’s effect on acne, intermittent fasting may produce better results than a ten-part skincare regimen or a few extra hours of beauty rest. The key to fasting’s benefit to your skin is the significant amount of anti-inflammation that is happening throughout your body. Your skin is the largest organ you have, and when your body is healthy, your skin will naturally follow suit.
Inflammation and stress naturally show up early on the skin, and fasting — in a healthy manner, with an adequate amount of water — is a great way to relieve stress throughout the body. While autophagy is working its magic to improve muscle health and to maintain nutrition in the brain, fasting allows the digestive system to rest and increases the billions of healthy bacteria in the gut. A well-functioning gut is vital for beautiful skin, because the digestive system has the highest number of immune cells of any part of the body. Optimal immunity will make sure that your skin is able to stop blackheads and acne in their tracks and help reduce the fine lines and wrinkles associated with aging.
This finding is not just anecdotal to people who fast for religious or health reasons. Research reveals the benefit of fasting on a host of skin ailments:
- Studies show that intermittent fasting helps improve wound healing in mice and also improves the thickness of their fur and improves blood supply to the skin.
- Fasting may work synergistically with any skincare regimen you have.
- Fasting may also lower the risk of inflammatory skin conditions like eczema and psoriasis.
Another critical part of a fast is drinking plenty of water. It’s important to remember that we’re encouraging water fasting, instead of a dry fast in which nothing — including water — is consumed. When all you have to take in is water — and the occasional non-caloric fluids — you tend to maintain your fluid levels. Drinking water and staying hydrated is crucial for skin health, and water fasts encourage this.
Slowing the aging process
Fasting can help you live longer. As fasting improves the body’s ability to heal and recover from negative events like disease and infection, the body is much more likely to thrive over the long term. This increased health is related to the body’s ability to oppose disease. Insulin and glucose, which drop when you fast, are strongly associated with disease and rapid aging. Fasting for about three days decreases blood levels of both by about 30 percent. IGF-1, the downstream effector of HGH, can also accelerate aging. Yet, fasting drops IGF-1 by up to 60 percent. Interestingly, this benefit is partially due to protein restriction, suggesting that fasting works in different ways from keto to improve long-term health.
Fasting reduces inflammation and improves the cells’ ability to heal. Fasting works its magic by promoting autophagy and a host of other hormone actors that help to decrease infection, illness, and disease, all of which associated with aging at a cellular level.
Many scientists believe that the telomere is essentially the epitome of the body’s fountain of youth. Telomeres are the protective cap at the end of chromosomes that protect chromosomes from unraveling. Because chromosomes are the blueprint of bodies and brains, short telomeres are more likely to lead to disease and aging because damaged chromosomes aren’t able to write out foolproof instructions to maintain a healthy body and mind. The length of telomeres decreases as you age — and it’s one reason scientist believe that people have a higher risk for disease, infections, and even cancer as they age.
Because fasting increase the cells’ ability to promote autophagy, and autophagy is a known factor in elongating telomeres, fasting is conclusively linked to a reduction in aging. Also, autophagy and telomeres are related in another way. The enzyme that increases telomere length — telomerase — also boosts cellular autophagy. In this way, autophagy and telomeres have a symbiotic relationship.
Studies show that long-term fasting — generally more than 24 hours — is needed to get the benefits of autophagy, and that’s why some authorities suggest a benefit of occasional long-term fasts of three or more days. Most people have to work their way up slowly to this goal, and some people should only do this under the supervision of a healthcare professional. If you have any preexisting medical condition, make sure to speak with your doctor before beginning any fasting routine.
Improving brain function
A commonly voiced concern is that fasting will lower the ability to think and accomplish necessary day-to-day obligations, but the opposite often happens. There are countless reports of people noticing that they feel sharper and more alert the longer they go into a fast. The first time you fast may be difficult because your body isn’t used to being without calories, but as it adjusts you may notice mental clarity that you’ve missed for a long time.
This makes sense: If humans had evolved to get brain fog whenever they were hungry, they never would’ve survived as a species. Can you imagine if our ancestors got more and more lethargic on the second or third day without food that they would have survived to the fourth day when they needed all their wits about them to catch dinner? Instead, their reaction times stayed sharp, their vision was excellent, and their mental clarity was never better. It’s more likely that they were most vulnerable those first few hours after having a satisfying dinner — likely similar to the post-Thanksgiving energy crash that you’re probably familiar with. With a full stomach, energy is diverted toward digestion of a large number of calories, and humans are neither as alert nor focused as when they’re hungry.
Interestingly, humans — and other mammals — have evolved so that low-calorie intake or fasting does not affect brain size. Most people, if they fast long enough (we’re talking about weeks without eating), will begin to notice muscle, bone, and other organs deteriorate. However, brain size will stay stable longer than anything else. This is crucial because your brain is your most potent asset. Outsmarting a predator was the best way to survive — because our ancestors were definitely not the largest or strongest animals in the jungle. Therefore, they were much more likely to survive than if their brain cells didn’t start to peter out as soon as they got hungry.
This is where the benefit of a keto/intermittent-fasting combination comes in. The brain needs some glucose to survive, even if you’re not consuming any carbohydrates. The liver can use gluconeogenesis to convert protein to glucose, meeting the brain’s needs even in an environment devoid of carbs. Studies show that with absolutely no food, your body and brain could survive for about 30 days. The rest of you will definitely shrink, but your body will prioritize nutrients going to your brain to keep your mind as sharp as possible until you eat again.
Most of the diseases in the modern age are related to inflammation. Whether cancer, heart disease, autoimmune disease, pain syndromes, or a host of other conditions, they all can be traced back to underlying inflammation in the body. This has led many nutritionists and doctors to search high and low for an “anti-inflammatory diet” that would help cure society of the ills that are affecting health and life span. Research shows that the best anti-inflammatory diet may well be fasting.
Individuals who fast long term (between one and three weeks at a time) have experienced benefits that are atypical for many conventional medical treatments and procedures.
Of course, type 2 diabetes is, at its core, an inflammatory condition and associated with the metabolic syndrome, a combination of five diseases that are all based on inflammation:
- Obesity (mainly when it’s around your waist)
- High blood pressure
- Insulin insensitivity (or high blood sugar)
- High triglycerides (the free fatty acids roaming around your bloodstream)
- Cholesterol problems (unusually low levels of high-density lipoprotein [HDL], the good kind of cholesterol)
Fasting can help address all these issues. Alternate-day fasting seems to be an excellent approach when dealing with any of these conditions. When people either drastically cut their calories every other day (to between nothing and as much as 500 to 600 calories per day), blood pressure drops, waistlines shrink, and they regain sensitivity to insulin. Various studies showed this effect in both overweight and healthy-weight people and took as little as a 15-day to a three-week commitment to alternate-day fasting. Daily intermittent fasting works as well.
To heal and be effective, the body has to go through natural periods of detoxification. This is more efficient and healthier than any detox diet you can do and is entirely self-sufficient. However, the effectiveness of this natural process can decrease as you age. Intermittent fasting to the rescue!
Christian de Duve, the 1974 Nobel Prize winner, realized how cells detox through a process called autophagy. Cells have lysosomes, essentially garbage disposal units that periodically search the cell for any damaged or abnormal parts that need to be fixed or removed so that the whole cell doesn’t become cancerous or damaged. This process is autophagy (literally meaning “self-eating”), and it’s the cell’s way of continually renewing itself. Autophagy is an integral part of the body’s work, but it’s inhibited by
The common factor of these three things is eating. Even if you’re following a keto diet, moderate protein will stop autophagy, and the small number of low-carb foods will affect it. There is no possible way of eating that will induce autophagy; however, some diets, like keto, may encourage its natural process more than others. When insulin levels rise, or amino acids from the digested pieces of your steak arrive in your bloodstream, this signals your body that more nutrients are coming in and old worn-out cells don’t need to be refurbished to produce energy. That means eating anything — even a ketogenic diet — regularly will block autophagy. Only fasting can combat this.
Yoshinori Ohusmi, a 2016 Nobel Prize winner, furthered the understanding of how the process works, revealing that autophagy is vital in
- Preventing cancer
- Cell survival
- Quality control of organs of every part of the cell
- Body-wide metabolism
- Management of inflammation and immunity
These are essential parts of how the body works and thrives, and fasting is able to turn up all these mechanisms so that they work at their optimal level. Another benefit of autophagy is that it keeps the brain in its best shape. Alzheimer’s disease, one of the most common neurodegenerative brain disorders in humans, happens when the brain is filled with an abnormal protein, called amyloid beta. This abnormal protein destroys the connections between brain cells, leading to difficulty with memory and learning. Autophagy tends to remove this abnormal protein, decreasing its ability to accumulate and lead to Alzheimer’s disease. Studies also show that fasting can help minimize the traumatic effects of
- Epileptic seizures
- Traumatic brain injury
- Spinal cord injuries
There are so many benefits to intermittent fasting that the better question to ask may be, “Are there any benefits to snacking?”