When it comes to fasting, a lot of emphasis is placed on what we eat (or don’t eat), which makes it easy to forget about another crucial element: staying hydrated. With the exception of people who fast from both food and water for the religious holiday of Ramadan, it’s generally not recommended to abstain from drinking water while fasting, and, in fact, dehydration can be a common side-effect of fasting even when you think you’re drinking enough water.

Remember there are numerous kinds of fasts. Here are just a few of them:

• The 5:2 fast: You restrict your calorie intake for two days per week (to approximately 500 calories per day for women and 600 for men).
• The 6:1 Pattern: Similar to the 5:2, you only reduce calorie intake to one day instead of two.
• “Eat Stop Eat”: This is a 24-hour total — taking in no calories, only water, black coffee or unsweetened tea — one to two days per week.
• The 16:8 fast: This fast involves only eating during an eight-hour window and fasting for 16 hours a day, every day of the week.
• Prolonged fast: These fasts can be anywhere from 3 to 7 days and might include water only or a liquid diet. They should be done with the approval of your doctor. These run the greatest risk of greater dehydration if not vigilant.

Since you get approximately 20 percent of your fluid needs from food, if you don’t increase your fluids when you fast, you could easily become dehydrated. Whole carbs, such as oatmeal, whole grain pasta, and brown rice absorb water while cooking. Other foods such as soups, watermelon, celery and many other fruits and vegetables contain a significant amount of water naturally. So, eliminating these items might also drop your hydration levels.

In addition to the lost fluids from food, part of the reason for increased risk of dehydration is a surprising link between carbohydrates and hydration. Carbohydrates are stored in your body as glycogen and attached to that glycogen is water. For each gram of stored glycogen, about 3 grams of water are stored with it. This is one of the reasons why you tend to lose weight so quickly when you cut carbs — some of it is water weight, says dietitian Jaime Mass, RD. It’s also why people often seem to gain weight back so fast when they begin to reefed.

Estimating your fluid needs

While medical professionals use several methods to estimate fluid needs — the Weight Method (Holliday-Segar Method), the RDA Method (Energy Method), and the Fluid Balance Method — there isn’t enough research to validate whether one or the other is more effective, though you may choose one that feels right to you.

Zero’s nutrition expert, Nicole Grant, RD, recommends estimating fluid needs for healthy adults by 30–35 mL of water per kg of body weight to start and adjusting from there. If you continue exercising while fasting, increase fluids slightly, and take into consideration your age and any disease states you may experience. Additionally, some medications may require extra fluids to be taken with them. Finally, if you’re in an environment with high temperatures, always take in more fluids.

If you’re engaged in a prolonged fast of more than several days, you can be at higher risk for dehydration, so maintaining electrolyte balance during a fast will give you the best hydration outcome and limit risks.

Always pay attention to your thirst, which is an important cue for dehydration, but remember it can be easy to overlook thirst if you’re busy or distracted, so it may not be the most reliable way to stay hydrated.

Maintain electrolyte balance

Electrolytes are substances everybody needs to manage, regulate, and maintain important bodily functions. These are depleted through physical activity and fasting, so you want to be sure you’re getting enough of the following electrolytes in your feeding windows. Remember, too, that the best way to absorb electrolytes is through whole foods, not supplements, unless you are at an extreme deficit and require supplementation.

· Sodium. Sodium depletion leads to headaches and muscle spasms. Make sure to get the recommended daily allowance for your weight and gender. For prolonged fasts of three or more days, you may need to supplement with bouillon for extra sodium. Depending on the type and duration of your fast, you may also need to increase your sodium intake greater than the recommended daily amount (RDA). On the other hand, certain populations need to be more cautious about their sodium intake, such as those with congestive heart failure, renal disease, or hypertension and may need to consume less than the RDA. Consult with your doctor.

· Potassium. The main job of this mineral is to regulate fluid in muscles and help nerves send signals. You can thank potassium for keeping you free of painful leg spasms.

· Magnesium. Among many jobs, this helps regulate muscle and nerve function and can aid in sleep. For prolonged fasts of three or more days, consider adding a magnesium supplement.

· Zinc. This mineral is well known for supporting testosterone production and nerve function. Don’t take this on an empty stomach, however — it can upset your tummy.

· Calcium. Calcium is key to your bones and your muscles. It helps your blood clot, your heart to beat, and your muscles to contract. You should be fine getting this in the form of food during your feeding windows.

Some signs that your electrolytes are too low include such symptoms as headaches, heart palpitations, lightheadedness, muscle cramps, and fatigue to name a few.

Analyze your urine

If you’re not quite sure of your hydration level, and you aren’t taking any medication or supplement that changes the color of your urine, Grant recommends using the color of your urine to indicate your general level of hydration. A concentrated yellow color likely equals dehydrated; very clear urine can mean overhydrated; and a light straw color is what you’re aiming for — it reflects good hydration.

Whatever approach you take to hydration, don’t make it a last priority when fasting. Proper hydration will make you feel better while fasting and help smooth your transition back to eating.

By Jordan Rosenfeld

Fasting is often touted as an effective method for losing weight, but new research finds it may also help save lives by reducing risk of strokes, and helping tissues recover after a stroke.

There are numerous risk factors for stroke, ranging from obesity to unhealthy lifestyle choices such as smoking, and the biggest contenders — high blood pressure, diabetes and heart disease. Studies show a positive link between fasting and a reduction in all of those risk factors, but a new study out of The British Journal of Nutrition shows even more promising results.

The study compares overweight participants who engaged in either the 5:2 fast or a daily caloric restriction (CR) diet. There are different variations on the 5:2 plan. One involves eating regularly for five days of the week but cutting calories to one quarter of regular calories consumed for two days. For example, if you regularly consume 2000 calories per day, you’d eat only 500 on the fasting day. In this study, the fasting participants consumed 600 kcals on their fasting days, no matter what their prior energy consumption had been. Researchers took down fat metabolism and blood sugar levels in subjects after eating.

High triglyceride levels in the blood is considered to be another serious risk factor for cardiovascular disease and stroke. Elevated triglycerides drive up LDL particle (LDL-P) numbers. The more LDL-P in the blood, the higher the chance the LDL-P will penetrate the endothelium or artery wall, which can then result in inflammation and plaque buildup. If these plaque build-ups burst, travel to the brain, become lodged, and restrict or prevent blood flow to the brain, an ischemic stroke will occur.

Subjects who participated in the above mentioned 5:2 fast study were able to clear triglycerides from their blood more quickly than the control group.

High blood pressure is another risk factor for stroke and cardiovascular disease. The fasting group’s systolic blood pressure reduced by 9% compared to just 2% in the daily diet group. Lowering systolic blood pressure reduces pressure on arteries, which may reduce the likelihood of heart attacks and strokes.

Another way fasting protects against strokes is by preserving a healthy cardiovascular system. One study of people who’d been on a CR diet for six years showed reductions in body fat, blood pressure and serum lipid and lipoprotein levels, which are risk factors for ischemic stroke.

In fact, the same study says, fasting may “precondition” the body to be able to prevent stroke by essentially imposing small, harmless “insults” on the brain that create a tolerance to ischemia (an inadequate blood supply to an organ).

Recovering after stroke

In addition to reducing risks of stroke, research finds that forms of CR may help support neurogenesis, the creation of new neurons and neuronal connections, after a stroke.

Neurogenesis requires two substrates called brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). BDNF is upregulated by CR in rodent models of stroke, and research in obese humans has shown shown that 25% CR for three months increased circulating levels of BDNF.

Another recent study in animal models found that intermittent fasting (IF) appeared to reduce tissue damage and neurological deficit after ischemic stroke “by a mechanism(s) involving suppression of excitotoxicity, oxidative stress, inflammation and cell death pathways in animal stroke model.”

IF has also been shown to have a positive effect on the inflammatory response and tissue damage after ischemic stroke by suppressing pathways of inflammation known as NLRP1 and NLRP3. In essence, lowering the production of inflammatory cytokines, which both IF and CR do, decreases susceptibility to stroke.

These associations between fasting and reduced risk of stroke, or recovery from stroke, are promising, and hopefully more research done in human models will continue to offer validity. However, it should also be noted that simply getting regular exercise, eating a healthy diet on non-fasting days and implementing lifestyle practices to reduce stress also reduce the chances of heart attack and stroke for not only overweight people, but those with a genetic predisposition.

Can Fasting Prevent Strokes and Aid Stroke Recovery? was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.

Preparing for a Fast

After reading all about the excellent benefits that fasting provides, you’re finally ready to try it out yourself. You could gobble down all the junk food you anticipate you won’t be eating for your fasting window, but it’s better to prepare your body for optimum success even before you begin fasting.

The magic of fasting happens when your body enters ketosis, a state where your liver glycogen has been depleted, and instead of using glucose as its primary fuel, it begins metabolizing and burning a different kind of fuel known as ketone bodies. This window is different for every person but on average begins after about 16–18 hours of fasting, or 2–4 days on a fasting mimicking diet, such as the keto diet.

If you’ve spent the week leading up to your fast eating lots of carbohydrates and processed foods, your liver may have a harder time burning up its excess glycogen. Give it a head start instead by eating the following foods:

Vegetables

Since the popularity of the keto diet, some people believe that all forms of fasting mean you should eat little to no carbohydrates. But many forms of fasting just ask you to restrict the number of calories or the window in which you eat them. So definitely don’t forget to eat your veggies; the carbs you get from many vegetables are not at all the same as the carbs you get from chocolate or bread. Lean toward veggies that provide you with extra doses of insoluble fiber. Hint: the green leafies, such as kale, spinach, swiss chard, bok choy. Also broccoli, cauliflower, and cabbage are high in insoluble fiber.

Insoluble fiber is the kind that isn’t broken down by your gut bacteria, and thus it passes through you, helping keep you regular, among many other benefits. According to Dr. Stephanie Estima, eating this kind of fiber also has a negligible effect on blood sugar levels and insulin, so eat up!

Fruit

If your sugar cravings go into high gear anticipating a reduction in sugar during your fast, try to feed it in the form of whole fruit, which also comes with fiber and nutrients, versus donuts, chocolate, or any other sweet treat. Not all fruit is ideal, either. You want to choose fruit that’s lower on the glycemic index (lower in carbohydrates), as well as lower in sugar/fructose and higher in fiber. Fruits like berries are among the best options to choose, as well as grapefruit and pears. Remember that fruit juices, while natural and often organic, lack the balancing effects of the fiber, vitamins, and other nutrients in a piece of whole fruit and can spike your insulin levels. So, avoid all juice prior to your fast.

Legumes

Since we’re talking about high fiber, don’t forget your legumes (unless you are on the keto diet, in which case, you’ll want to limit them), which include beans, lentils, and peas. Legumes are also high in protein, which can make a nice substitute for meat if you want to take a break before and after your fast. Some legumes, such as white beans and lentils, are also high in resistant starch — carbohydrates that don’t break down easily in the gut and thus don’t interfere with keto diets because they have negligible impact on blood glucose and insulin levels. These can be added to salads, lean protein, or consumed on their own. Most legumes can be made even more digestible by soaking them (especially if they’re dry to begin with), typically overnight.

Healthy fats

Fat has long been vilified, but research shows that not all fat is created equal. You need healthy fats for a number of important bodily functions including your hormone production, and the healthy development of your brain, immune system, nervous system, and blood vessels. Healthy fats contribute to feeling full and satisfied after eating and can set you up to be less hungry during your fasting periods. Avoid trans fats and minimize animal fats such as bacon, butter, and dairy, but embrace your essential fats such as avocados, olives, and coconut oil. Also, in moderation, enjoy fats from nuts such as almonds, Brazil nuts, and cashews (particularly if they are raw to begin with and have no added sugars or salt). Also tasty and healthy in moderation are seeds such as sunflower, pine nuts, and pumpkin seeds, as well as chia and flax seeds — though the latter two may need to be blended or chopped into other food for optimum taste.

Protein

You could ideally get all the protein you need from the veggie and legume options mentioned above, which would be a nice way to kick-start a fast. But if you still enjoy other forms of protein, make sure you’re choosing lean, organic options. Perhaps eat a little less meat in the week leading up to your fast, or transition from red meat to chicken or pork. Consider replacing meat with only eggs or eating a soy-based protein such as tofu or tempeh. You can also get a lot of protein from dairy, but balance your intake so you’re not suddenly upping your dairy intake, which can be higher in fat and calories.

Macros and meal timing

Other key areas to consider before a fast are: macronutrient distribution (i.e., the percentage of kcal that falls into the carbohydrate, protein, and fat categories), the quality of your nutrient intake, and meal timing. Being purposeful in your approach to these can make the transition into a ketogenic state, and thus your fast, much easier, especially if a prolonged fast is your goal. This will help keep your hunger low and energy level up so you can obtain the benefits of fasting sooner.

Consider cleaning up your diet and altering your macronutrient distribution about two days to one week prior to your fast (depending on the type of fast you are completing and the duration). This means cutting out the sugar and processed carbs, and beginning to decrease the total amount of carbs you are consuming, specifically those from the previously mentioned categories, as well as some from the fruits and grains/starches categories. Keep protein about the same and you can increase your fat consumption slightly if needed. For example, instead of having a macronutrient distribution that is 50% carbohydrates, 20% protein and 30% fat, consider shifting that closer to a 20% carbohydrates, 20% protein and 60% fat during the days leading up to your fast.

Gradually shortening your feeding window about one week prior to your fast can also help train your body on how to function without food and get you into a more fat-adapted state. For example, if you don’t do time-restricted feeding already, you can start with a 14/10 feeding/fasting time frame and slowly decrease that feeding window closer to a 16/8 or even 18/6 the day before your fast. If you are already an avid time-restricted feeder, consider going to one meal a day (OMAD) or decreasing total portion sizes a few days before the fast.

Coffee/caffeine

A final note about coffee/caffeine. If you plan to do a fast without caffeine and are a big coffee/tea drinker, plan to start tapering your intake down one week prior to your fast to avoid caffeine withdrawals. Even those who drink one cup per day could benefit from a reduction in caffeine a few days prior to their fast.

Perhaps the best way to approach fasting in general is to treat it as the beginning of a shift in how you treat your overall health. Before you get your first fast underway, begin to eat as healthy as you can.

What Should You Eat to Prepare for a Fast? was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.

If you’ve embarked upon one of the many varieties of fasts — where you take in little or no food for a stretch of time — at some point you’ll eventually need to break your fast and begin eating again. Experts say you shouldn’t let your hunger or cravings drive you, but rather go slowly and thoughtfully into what you eat first.

When to break your fast?

When you start eating again depends upon the fasting protocol you’ve taken on. If you’re doing time restricted feeding, many people choose to stop eating around 7 or 8pm, fast overnight, skip breakfast, and have their first meal around 11am or 12pm, at lunch essentially. Generally, you don’t want to break a fast at night since you’ll be using fewer calories as you head to bed.

Go slow

No matter the kind of fast you’ve done, be it time restricted feeding for some hours, or a water fast for a day or more, it’s most important that you ease back into eating so as not to overwhelm your digestion or undo some of the good effects you’ve achieved by fasting. A loaded cheeseburger might sound fantastic, but it probably won’t feel so good going down.

One expert recommends you halve the number of days you fasted and used that as a guide for reintroducing foods. So, if you fasted for four days, take two days to ease your way back into eating.

Consider starting with broths and liquids for the first meal, and possibly the first day, if you’ve been on a longer fast. The less sugar in these liquids, the better, as those can create bloating and digestive irritation. Once you introduce food, expect to gain back a certain amount of water weight due to adding back in some carbs and replenishing your glycogen stores. However, be sure to continue to drink lots of water as well. You might have become dehydrated while fasting, which is common if you don’t stay on top of your fluid intake.

Post-fasting is also not a great time to experiment with new foods or recipes you haven’t tried before. Your body might not be prepared to properly digest these new foods, so it is best to first reintroduce something that is familiar to you to ease the transition. Wait until you are back into a normal eating routine to start experimenting with new foods.

Gradually introduce foods

When you start eating again, choose foods that are low on the glycemic index because too many carbs, especially carbohydrates that are easily digested and quickly absorbed, can spike insulin levels. One fasting expert recommends eggs, avocado, nuts and spinach as good examples to introduce first.

Another nutrition expert recommends that you start with soft-cooked foods like vegetables, since these are easier to digest. Slowly move up to foods with whole grains and high fiber because too much of these after not eating can lead to constipation. Add in raw foods last, as these can irritate your digestive tract.

When transitioning off a prolonged fast, it may be better to start with small servings and have no more than 500 calories per meal. This slow transition will help your body adapt to having higher amounts of nutrients again. In rare cases, people who have gone a long time without eating — usually more than 10 days — or who are malnourished prior to starting a fast can be at higher risk of a dangerous condition known as “refeeding syndrome.” This is a potentially fatal syndrome that can occur due to shifts in fluids and electrolytes after macronutrients are too rapidly reintroduced into the body. As long as you are in good health going into your fast, transition slowly back to your normal diet and are under the care of a health professional before, during, and after fasting, this is unlikely to occur.

If you start craving sugar again after a fast and think you’ll quell your sweet tooth with fruit, go carefully, particularly if you are fasting for weight loss or to balance your blood sugar. Even too much natural fructose can negatively impact insulin sensitivity. If you must eat fruit, choose those that are lower on the glycemic index and higher in fiber, such as berries, apples, or pears.

To help overeating, have a plan in place for breaking your fast. For prolonged fasts, map out your meals for the week after your fast. Knowing what and how much you will be eating the days following your fast will help reduce your risk of binge eating and choosing poor quality foods. Meal planning apps or meal prep kits are great tools to help with this.

Other considerations

A small portion of protein at your first meal such as eggs or chicken can be a good option, as they provide essential amino acids to help rebuild and repair the body. When you fast, growth pathways such as IGF-1 and mTOR are suppressed. Amino acids stimulate both of these, so once you reintroduce amino acids from protein sources post fast, you then activate this beneficial growth period.

What you eat isn’t the only consideration after fasting; another expert recommends you chew your food very thoroughly, as many as 30 times per bite, to make sure your food is easily digested.

If you’re anxious about digestion, consider adding in a probiotic, either in the form of a supplement or by eating foods that have naturally occurring probiotics in them, such as sauerkraut, miso, and, when you feel ready for dairy, yogurt.

Beyond just breaking your fast, also consider your overall eating habits. If fasting is your only answer to getting healthier, but you don’t eat well the rest of the time, fasting is unlikely to give you the results you’re seeking.

Breaking Your Fast was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.

While fasting is getting great press for its numerous health benefits, it’s not for everyone. There are a variety of reasons for certain people to avoid fasting, either short or longterm, to stay in optimum health. Here are just a few groups who should likely avoid fasting or work closely with a doctor to devise a specialized plan:

Pregnant or Nursing Mothers

Pregnant women need to be sure to take in an appropriate number of calories and nutrients during gestation. While research varies on the outcomes of fasting during pregnancies, there is some evidence that fasting while pregnant may increase the likelihood of preterm labor and result in babies with lower birth weight or shorter stature. Most significantly is the finding that when a pregnant mother fasts, fetal breathing drops, though it resolves once the mother eats again.

When fasting, pregnant and nursing mothers both have a higher risk for hypoglycemia due to lower blood glucose levels and are at risk of dehydration, which can have an impact on the fetus’s amniotic fluid levels and breast milk production. Therefore, it is generally not recommended.

Eating Disorders

For people struggling with eating disorders such as anorexia nervosa or bulimia, fasting is not recommended, as it can easily play into disordered eating patterns, such as starving or vomiting up meals. Some signs that fasting is becoming disordered eating include:

· Anxiety about eating

· Extreme fatigue (often from lack of nutrition)

· Dramatic changes in hormones or menstrual cycle

To find out if you are at risk of an eating disorder, the National Eating Disorders Association offers this self-assessment tool.

Type 1 Diabetes

Fasting is not recommended in patients whose type 1 diabetes is poorly controlled, including those who have a history of severe hypoglycemia and/or diabetic ketoacidosis; anyone who has additional conditions such as angina, hypertension, or kidney problems; those who are not properly taking their medication; who perform intense physical activity; or are elderly with diabetes. With the permission and observation of a physician, some people with Type 1 diabetes, which is an autoimmune disease, may be able to fast, however, that comes with a huge caveat, and should not be undertaken without medical permission first because fasting can lead to hypoglycemia.

This meta-analysis shows that fasting as a type 1 diabetic can come with some risks, such as hypoglycemia and hyperglycemia. However, it also suggests that the type of insulin therapy used while fasting, along with the supervision of a healthcare practitioner who can adjust the insulin therapy, can mitigate the risk of these adverse events.

Type 2 Diabetes

Under the supervision of a healthcare provider, fasting for people with type 2 diabetes may be safe so long as the diabetes is under control. One study found that a seven day liquid fast of only 300 calories per day proved safe for those with type 2 diabetes. However, another study on people with type 2 diabetes showed that the chance of low blood sugar incidents doubled on fasting days versus non-fasting days, which could lead to hypoglycemic events. So, as long as you are under the care of a medical practitioner who is knowledgeable about fasting, it may be an option for you. Fasting is also shown to be effective for people who have pre-diabetes, but so is simply reducing carbohydrate intake and adding more exercise.

The Elderly

While there are no hard guidelines about the safety of fasting as it relates to age, medical professionals warn that elderly folks with any chronic health conditions, especially diabetes, kidney problems, or heart disease, should not fast as it could be dangerous to their health. If an older adult is in good health and not taking any medication, fasting under the supervision of a doctor may be okay, however, older adults are at greater risk of dehydration, and must be careful to replenish water and electrolytes.

Youths

Growing bodies need good nutrition as consistently as possible. Therefore, fasting is not recommended for kids and teens, who undergo rapid growth and are still developing. For youths that need to lose weight, caloric restriction and reduction of carbohydrates may be just as effective.

Medications

The first rule of fasting is to make sure you consult with your doctor before you begin. This is especially important if you take any medications. Every medication is different. One of the biggest concerns is that many medications need to be taken with food and at a certain time of day, which may interfere with a fasting window, or putting off a medication to a later eating window could impair the medication’s efficacy. Additionally, glucose-lowering medications such as metformin, berberine, and sitagliptin, as well as exogenous insulin should be closely monitored and adjusted during a fast due to their glucose lowering effects. Depending on the type and the duration of the fast, some medications need to be held until the fast is over or moved to a different time of the day or week.

Fasting can also lead to dehydration if one is not careful, which can reduce blood pressure, impair the body’s electrolyte balance, have a negative effect on heart function, and potentially cause kidney damage. If you are taking a medication for blood pressure or kidney issues, this could be very dangerous.

Current Medical Conditions

Anyone with a medical condition should consult their physician before undertaking a fast. Fasting can cause changes in blood sugar, hormones, and blood pressure, which can affect numerous health conditions.

You should also consider situational and external factors when considering a fast including, but not limited to: periods of high stress, travel — especially changing time zones, which can interrupt your circadian rhythm — or high-intensity and prolonged exercise. Each of these situations can put you at a higher risk for hypoglycemia, as well as electrolyte and fluid imbalances. When choosing to fast, these situations need to be considered and a conversation with your doctor or supervising healthcare practitioner is needed.

In Conclusion…

Ultimately, while fasting may sound great, be safe. Consider your specific health conditions and work with your doctor to advise you on the best plan. There are many different fasting protocols — from multiple day, water-only fasts to time-restricted feeding — that support a range of goals and have varying degrees of safety for certain populations. So, when you’re deciding if, when, or how to fast, always consult with a medical professional. Your health will thank you.

Should You Avoid Fasting? was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.

Fasting — where you restrict taking in calories for an extended period of time—appears to bring with it some pretty remarkable health benefits. These include weight loss, changes to risk factors for diabetes and heart disease, and longer life.

Researchers have been trying to get to the bottom of why fasting is linked to longevity for years. Lab mice and monkeys that fast in lab studies have a tendency to live longer than their regularly fed peers.

Research finds that restricting calories turns on genes that tell cells to preserve resources. The cells go into a preservation or “famine mode,” where they are, remarkably, much more resistant to disease or cellular stress. They also enter a process known as autophagy, where the body begins to clean out the old, unwanted, and unneeded cellular material, as well as fixing and recycling damaged parts.

In one study, mice that fasted for 24 hours showed high numbers of autophagosomes, the signs that autophagy is working. Now, we have to be careful linking this directly to humans because mouse metabolism is much faster than ours. While autophagy is very difficult to measure outside of a lab environment, many experts agree that the autophagy process initiates in humans after 18-20 hours of fasting, with maximal benefits occurring once the 48–72 hour mark has been reached. If this sounds daunting, keep in mind that doing intermittent fasts will still give you benefits, but periodically (a few times a year depending on your personal risk factors) you might consider a longer fast to fully activate autophagy and do some spring cleaning for your cells. Of course, you should always consult with your doctor before embarking on any fasting regimen.

Stimulating autophagy does several things: it clears out old, unwanted cellular materials and proteins, and it also stimulates the production of growth hormone, which regenerates fresh cellular material and fuels up cell renewal. If your body has recently had an infection, autophagy may be able to destroy lingering bacteria or viruses.

Autophagy is not only linked to increasing longevity, it’s helping researchers to better understanding degenerative diseases such as Parkinson’s and Alzheimer’s. When autophagy does not take place frequently, the body collects a variety of cellular material, including proteins that show up in large quantities in Alzheimer’s, Parkinson’s, and even cancer: amyloid beta or Tau protein. Researchers believe that prolonged bouts of autophagy might be able to clear the brain of those excess proteins, thus potentially preventing the development of those diseases.

How to achieve autophagy?

While drug companies are working on creating a pharmaceutical panacea to stimulate autophagy, and some diet and fitness bloggers claim that certain supplements can cause autophagy, there is really only one proven way to trigger it: through fasting. Nutrient deprivation triggers autophagy.

Autophagy signaling in the body involves two key pathways when the body’s nutrients become depleted:

mTOR,or mammalian target of rapamycin, regulates the nutrients that affects cellular growth, protein synthesis, and anabolism. It is linked to the activation of insulin receptors and new tissue creation.

AMPK or AMP-activated protein kinase helps to maintain energy homeostasis and activate the body’s backup fuel mechanisms.

mTOR and AMPK both are attuned to the presence of nutrients in your body. These two pathways help your body decide if it will activate a growth response — mTor — or go into autophagy — AMPK.

Autophagy also works in concert with two key hormones: glucagon and insulin. People with diabetes or hypoglycemia have trouble regulating, or are overly sensitive to insulin. When insulin goes up, glucagon goes down and vice versa. When you fast, you drop insulin and increase glucagon, which stimulates autophagy.

However, it’s not quite that simple: to induce autophagy, you need low liver glycogen, which is usually only achieved after about 14–16 hours of fasting, but is even more likely to happen after 24 hours, so it’s a serious commitment.

Despite these awesome benefits, the level of fasting required to activate autophagy isn’t for everyone. Some people feel low-energy, moody, and have trouble sleeping during such fasts. Strive for balance and always check in with your healthcare providers.

Fast Your Way to Autophagy was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.

If you’re not up to wearing green this St. Patrick’s Day, try eating green instead. When it’s time to break your fast, do it with some super healthy green foods. These foods are rich in a variety of vitamins and nutrients that can boost your health and taste great going down.

Spinach

This humble green leafy vegetable has great versatility — you can use it raw in salads or cook it in just about anything — soups, stir fries, etc. It also packs an incredible nutritional punch. 100 grams of raw spinach contains 188% of your daily value (DV) for vitamin A, 47% vitamin C, 15% iron, and 10% calcium.

It’s also full of folate (also known as folic acid), which not only helps to prevent birth defects such as neural tube defects, but supports healthy red blood cell production and is essential for your DNA to form properly.

Cabbage

Despite the fact that cabbage may look a bit like lettuce — the ball-shaped veggie, comprised of layers of leaves, is actually a cruciferous vegetable in the Brassica family, which includes broccoli (it also comes in white and purple varieties). This humble, rabbit-friendly veggie lends itself well to stir fries, soups and stews, as well as in fermented dishes like sauerkraut (which contains healthy probiotics, good for the digestive system).

And while not everyone loves its flavor, or its pungent, sulfurous scent when cooking, cabbage is remarkable in its health benefits. A chemical in cabbage called DIM (3,3'-diindolylmethane) has been shown to have protective effects against radiation, such as in chemotherapy. It’s extremely high in vitamins such as vitamin K, offering 85% of the daily value, 54% of vitamin C, and 10% of folate.

The compounds that give it its bitter flavor, called glucosinolates, have been shown in studies to be cancer-protective, particularly against lung and esophageal cancers.

Steam it, sauté it, or pair it with corned beef—you can’t go wrong.

Avocado

This seed-heavy fruit — yes, it’s a fruit! — delivers heart-healthy fats and nutrients in a tasty package. Though avocados do contain fats, it’s the healthy monounsaturated fats, namely oleic acid, which are linked to low incidences of cancer. You won’t find any saturated fat, cholesterol, or sodium in these. What’s more, avocados have more potassium than bananas, an essential electrolyte (important to replenish after fasting), which is linked to healthy blood pressure.

Additionally, in one 100 gram serving of avocado you’ll get important vitamins such as vitamin K, folate, vitamin C, vitamins B5 and B6, and vitamin E.

Whether you eat it on toast, mix it into guacamole, or just consume it clean, your body will thank you for providing it with this delicious food.

Arugula

Of all the salad greens, one that often flies under the radar is the slightly spicy and nutty arugula, also known as “rocket” or “roquette,” a leafy green from the Brassicaceae family.

Like other leafy greens, it’s packed with vitamin A, B9, and K as well as carotenoids and antioxidants, and it’s high in fiber. Arugula also contains dietary nitrates. Research has shown that these might reduce hypertension in some people by increasing blood flow and widening your blood vessels.

Spice up a boring salad, garnish a plate, or toss it on top of pizza for flavorful delight.

Kiwi

This tangy tropical fruit with the green interior and brown skin is about as healthy as a fruit can be. Every part of the fruit is edible—even its fuzzy brown skin, which provides high fiber, and its tiny black seeds. It’s loaded with vitamin C (273% of your daily value!) and antioxidants, good for a healthy immune system, and linked to supporting asthma.

It also contains an enzyme called actinidin that supports digestion. And it’s full of other bioactive substances that may help reduce blood pressure. Even more astonishing, a Norwegian study found that eating several kiwis a day can reduce blood clotting. So eating a fruit salad isn’t just delicious; it’s medicine.

Whichever green foods you choose, whether from this list or the numerous others in existence, your body will thank you.

Eating Green was originally published in Zero Fasting on Medium, where people are continuing the conversation by highlighting and responding to this story.