Intermittent fasting is an consuming sample that cycles between intervals of fasting and consuming. Supporters declare a variety of potential well being advantages, like weight reduction, improved metabolism, and even wholesome ageing and longevity. (1)
However whereas many individuals have discovered success with intermittent fasting, it’s not for everybody and is probably not more practical than different consuming patterns.
Right here’s a deep dive into the science behind intermittent fasting. Study its advantages, dangers, and when you ought to attempt it.
What Is Intermittent Fasting?
Intermittent fasting (IF) is a dietary strategy that alternates between structured fasting and consuming instances, or home windows. Not like conventional diets, IF doesn’t essentially harp on what you eat however quite when you eat.
This flexibility is what has made IF a preferred selection for these seeking to handle their weight and enhance well being with out eliminating particular meals teams or drastically altering their eating regimen.
There are a number of well-liked strategies of intermittent fasting, and their construction varies drastically:

Knowledgeable Opinions & Views
Intermittent fasting has obtained some constructive suggestions from specialists within the diet area, although it’s not with out its main caveats.
In keeping with Joanna Gregg, a registered dietitian with MyFitnessPal, IF may be particularly helpful for people who wrestle with late-night snacking or overeating in the course of the day. By limiting consuming to particular home windows, some folks naturally cut back their complete calorie consumption, which may result in weight reduction.
Analysis additionally means that fasting for 8-16 hours might enhance inflammatory markers and insulin sensitivity, which might help cut back the danger of persistent ailments like diabetes. (2) Nonetheless, Gregg advises warning for people with sure well being circumstances, together with Sort 1 diabetes, or for individuals who are pregnant or breastfeeding (1). These people ought to examine with their medical doctors.
Daisy Mercer, one other MyFitnessPal dietitian, emphasizes the fat-burning advantages of intermittent fasting. Throughout fasting intervals, the physique depletes its shops of sugar (glycogen) and begins burning fats for vitality, which could promote weight reduction. (2) Nonetheless, she notes that fasting isn’t appropriate for everybody, particularly these with diabetes. Fasting may cause blood sugar ranges to drop dangerously low. (1)
Lastly, Stephanie Nelson, MFP’s lead diet scientist and registered dietitian, reminds us that intermittent fasting isn’t a magic resolution for weight reduction. It really works by serving to folks create a calorie deficit, which is the actual driver of fats loss. Nelson warns in opposition to overly restrictive diets which might be troublesome to keep up in the long run. Sustainable, small calorie deficits will be simply as efficient. (3)
Concerning the Consultants:
Caroline Thomason is a registered dietitian and authorized diabetes educator. With 12 years within the business, she’s printed in 40+ publications, a CPG guide and advisor, a speaker, broadcast spokesperson, and recipe developer.
Joanna Gregg, RD, is a meals information curator at MyFitnessPal. She earned her bachelor’s diploma in Vitamin from Georgia State College and obtained her Grasp’s diploma from The College of Nebraska.
Daisy Mercer, RD, is a Meals Information Curator at MyFitnessPal. She graduated along with her bachelors of Meals Science and Dietetics from Colorado State College and accomplished her dietetic internship with the VA San Diego Healthcare system.
Stephanie Nelson is a Registered Dietitian and is MyFitnessPal’s in-house diet knowledgeable and diet scientist. Passionate for selling wholesome life, Stephanie graduated from San Diego State College with a concentrate on analysis and illness prevention.
The Historical past and Evolution of Fasting
Fasting has been practiced for hundreds of years for each non secular and well being causes. Spiritual fasting practices, resembling Ramadan in Islam and Yom Kippur in Judaism, emphasize the significance of abstaining from meals for reflection and non secular purification. (4)
Early people additionally fasted unintentionally when meals was scarce. And even immediately, you quick in a single day whilst you sleep. Fashionable intermittent fasting has had a well being focus and is backed by some analysis to assist advantages like improved metabolism, longevity, and psychological readability. (1)
How Intermittent Fasting Works
Whenever you quick, the physique first burns by saved vitality within the type of glycogen. As soon as glycogen shops are depleted, usually after 12 to 16 hours of fasting, the physique enters a state known as ketosis, the place it begins to burn fats for gasoline. (5)
Ketosis isn’t a magical trick for fats loss. You continue to should be in a calorie deficit over the course of the day to drop some pounds.
Right here’s an summary of the commonest intermittent fasting strategies:
12/12 Methodology
That is essentially the most beginner-friendly fasting strategy. You quick for 12 hours and eat usually for 12 hours. For most individuals, that is as simple as setting an inexpensive nighttime consuming cutoff, resembling after 7 pm.
The MyFitnessPal in-app timer presents 3 decisions: a 12 hour, 14 hour, and 16 hour quick. In case you’re new to fasting, you may wish to start with a 12-hour quick.
16/8 Methodology
You quick for 16 hours and eat throughout an 8-hour window. Most MyFitnessPal members utilizing the Intermittent Fasting Tracker characteristic select this technique.
It’s versatile sufficient to suit into most day by day routines—many individuals merely skip breakfast and eat lunch and dinner inside the 8-hour window. This technique works for a lot of of us as a result of it provides your physique time to burn fats in a fasted state whereas nonetheless permitting you to get pleasure from meals throughout an inexpensive timeframe.
Nonetheless, it’s necessary to keep in mind that no fasting technique is a magic repair for weight reduction, and even a plan like this requires dietary steadiness and consistency to see outcomes.
5:2 Weight loss plan
The 5:2 eating regimen is one other well-liked choice the place you eat usually for 5 days of the week, then limit your calorie consumption to round 500-600 energy on two non-consecutive days every week.
This technique permits for flexibility because you’re solely calorie-restricting twice per week, however it’s necessary to remain conscious of your diet decisions on fasting days to keep away from feeling overly hungry or fatigued.
When attainable, select protein and veggies for greater quantity meals which might be decrease in energy. You possible will nonetheless expertise some starvation, and if it feels unmanageable, scaling again in your fasting window might help.
Whereas it may be efficient for some, it’s not a fast repair—long-term success with any fasting plan depends upon consistency and a balanced strategy.
Eat-Cease-Eat
With Eat-Cease-Eat, you quick for twenty-four hours a couple of times per week. It’s a extra excessive technique that may be efficient for fats loss, however it’s additionally difficult since going a complete day with out meals can result in intense starvation and low vitality.
In case your life-style naturally permits for one of these consuming sample, or when you discover that you just don’t eat very a lot someday per week, this could possibly be a match for you. Total, as a dietitian, this isn’t one thing I might suggest for most individuals.
This technique can result in damaging unintended effects like fatigue, irritability, or overeating throughout non-fasting days. It is a extra excessive method of fasting. It additionally might have an elevated danger for binge consuming because of fasting for too lengthy and going into your subsequent consuming window ravenous.
Alternate-Day Fasting
Alternate-day fasting includes fasting each different day, with round 500-600 energy consumed on fasting days. This technique can result in important calorie discount over time, however it’s one of many tougher approaches to keep up as a result of frequent fasting.
Some folks might expertise the psychological fatigue of fasting each different day. On non-fasting days, it’s essential to eat balanced meals to keep away from overcompensating. Whereas it may be efficient for some, the restrictive nature of fasting each different day might trigger unintended effects like low vitality or nutrient deficiencies if not accomplished fastidiously.
The sort of fasting is probably going not match for most individuals as it may be fairly restrictive and each mentally and bodily draining.
OMAD (One Meal a Day)
OMAD, or One Meal a Day, is one other excessive fasting technique the place you quick for 23 hours and eat all of your day by day energy in a single meal throughout a 1-hour window.
Whereas some folks discover it simplifies meal planning, it may be troublesome to fulfill all of your dietary wants in only one sitting. This technique can result in overeating or digestive discomfort, and its restrictive nature may trigger disagreeable unintended effects like binge consuming, fatigue, or nutrient imbalances.
This may be match for individuals who already wish to eat as soon as a day or have a shift work sort of schedule. You’ll additionally wish to take into account what time you wish to train and when you’ll have sufficient vitality for motion all through the day, with just one meal a day.
Nonetheless, going for lengthy intervals of time with out consuming isn’t one thing we suggest for most individuals who wish to eat more healthy.

You may additionally like:
What To Know Before Starting Intermittent Fasting >
How Intermittent Fasting Impacts the Physique
Intermittent fasting might impression a number of physiological processes that may positively have an effect on well being:
- Metabolism: Fasting shifts the physique into ketosis, selling fats burning as the primary supply of vitality. (2)
- Insulin ranges: Fasting might enhance insulin sensitivity, which helps regulate blood sugar ranges. (2)
- Mobile restore: Fasting prompts autophagy, a mobile restore course of the place the physique clears out broken cells, doubtlessly lowering the danger of ailments and selling longevity. (6) Nonetheless, it’s necessary to notice that the method of mobile restore appears to happen in many alternative calorie deficit settings. Fasting isn’t the one technique to obtain this well being profit. (6)
- Hormones: Fasting may regulate starvation hormones like ghrelin and leptin, serving to management urge for food as a result of taking longer breaks from meals. (7)
Well being Advantages of Intermittent Fasting
Weight Loss and Fats Loss
Intermittent fasting could also be an efficient device for weight reduction primarily as a result of it restricts your consuming instances, which could cut back your total caloric consumption. When your physique is in a fasted state, it begins to burn saved fats for vitality, notably visceral fats—the sort saved round inside organs. (8)
Visceral fats is a sort of fats related to the next danger of significant well being circumstances like coronary heart illness and kind 2 diabetes. Research counsel that intermittent fasting could also be particularly useful in concentrating on this cussed fats whereas additionally preserving muscle mass, which will be difficult with conventional calorie-restricted diets. (8)
Bear in mind, it’s necessary to pair intermittent fasting with balanced, nutrient-dense meals to make sure long-term success and stop overeating throughout consuming instances.
Metabolic Well being
Intermittent fasting might enhance a number of markers of metabolic well being, making it a possible technique for stopping metabolic ailments resembling sort 2 diabetes and coronary heart illness. (1)
By lowering insulin ranges and growing insulin sensitivity, IF might assist the physique use glucose extra effectively and reduces the danger of insulin resistance, a precursor to diabetes. (9)
Plus, fasting could also be related to decrease ranges of irritation, which is linked to many persistent ailments. By giving your digestive system a break and permitting your physique to concentrate on restore processes, intermittent fasting might enhance total metabolic perform and assist decrease blood strain, ldl cholesterol, and blood sugar ranges. (10)
Longevity and Anti-Growing old
One of the thrilling potential advantages of intermittent fasting is its potential hyperlink to longevity and anti-aging unintended effects. Some information have proven that fasting can enhance lifespan and defend in opposition to age-related ailments by selling a course of known as autophagy. (6) Autophagy is actually your physique’s method of cleansing up broken cells and regenerating newer, more healthy ones. (6)
This mobile restore course of not solely helps to decelerate ageing but in addition protects in opposition to ailments like Alzheimer’s and most cancers. (11) Whereas human research are nonetheless ongoing, the early outcomes counsel that intermittent fasting might have anti-aging advantages by enhancing the physique’s pure restore mechanisms.
Cognitive Perform and Mind Well being
Fasting may present important advantages to your mind. Intermittent fasting has been proven to extend the manufacturing of brain-derived neurotrophic issue (BDNF), a protein that helps the expansion of recent neurons and protects current ones from injury. (12)
BDNF performs an important position in studying, reminiscence, and total mind well being. It could assist cut back the danger of neurodegenerative ailments like Alzheimer’s and Parkinson’s. (13) Moreover, by lowering irritation and oxidative stress, fasting helps defend mind cells and promotes higher cognitive perform over time. (13)
We’d like extra human analysis on this space to make extra substantial claims, however the preliminary analysis is attention-grabbing.
Dangers and Drawbacks: Is Intermittent Fasting Secure for Everybody?
Regardless of its advantages, intermittent fasting isn’t wholesome for everybody. Listed here are some potential dangers for various populations.
Ladies and Intermittent Fasting
Ladies’s our bodies are notably delicate to modifications in vitality consumption, and intermittent fasting (IF) can have distinctive results on their hormonal steadiness. Calorie restriction from fasting might result in hormonal disruptions, notably in reproductive hormones like estrogen and progesterone, that are accountable for regulating menstrual cycles. (14)
Extended fasting may cause irregular intervals or, in excessive instances, amenorrhea (the absence of menstruation), which is an indication that the physique isn’t getting sufficient vitality. (14)
Ladies who’re pregnant or breastfeeding are sometimes suggested to keep away from intermittent fasting until explicitly really helpful by a healthcare supplier. Fasting can result in nutrient deficiencies which will hurt each the mom and little one.
For girls in different life phases, shorter fasting home windows (12-14 hours) may be a safer strategy to keep away from hormonal imbalances.
Fasting for These with Medical Situations
Folks with underlying medical circumstances must be particularly cautious when contemplating intermittent fasting.
People with diabetes should be conscious that fasting can result in harmful fluctuations in blood sugar ranges. (1)
For these with coronary heart illness, fasting may impression the cardiovascular system if it results in fast weight modifications, blood strain fluctuations, or dehydration.
Anybody with a historical past of consuming issues ought to keep away from fasting. Intermittent fasting might set off unhealthy behaviors associated to meals management. (15)
Consulting with a healthcare supplier is important earlier than beginning intermittent fasting to guage dangers and be sure that it’s secure to your situation.
Frequent Aspect Results
Intermittent fasting can set off a spread of different unintended effects even when you don’t have a well being concern.
Particularly within the preliminary phases because the physique adjusts to new consuming patterns, among the most typical unintended effects embrace complications, dehydration, fluctuations in blood sugar ranges, fatigue, and dizziness. (16) Starvation throughout fasting intervals might disrupt sleep cycles or trigger insomnia.
These unintended effects may enhance as soon as your physique adapts to a fasting schedule. Watch your signs, keep hydrated, and eat nutrient-dense meals throughout consuming home windows to attenuate these points. (17)
Selecting the Proper Fasting Methodology for You
Contemplate these elements of your life-style and meals preferences earlier than fasting and decide the correct one for you.
- Work schedule: Work to align fasting along with your work schedule to remain sharp whereas working. Longer shifts might require shorter fasting home windows to keep up vitality and focus.
- Way of life: Contemplate your social and day by day actions. A versatile fasting plan will work higher for busy or social life.
- Train routine: Time your meals round exercises for sufficient vitality. Excessive-intensity exercises might require shorter fasting intervals for correct restoration and vitality.
- Meal preferences: Select a fasting technique that fits your consuming habits. Bigger, much less frequent meals may fit higher with fasting if that’s your pure tendency.
- Binge tendencies: In case you’re vulnerable to binge consuming, fasting might set off overeating and may not be best for you. Go for versatile consuming home windows to keep away from restriction.
- Sleep schedule: Keep away from fasting too near bedtime to stop sleep disruptions. Alter your fasting intervals to suit your pure sleep patterns for a restful evening.
- Well being historical past: When you have a historical past of well being circumstances like diabetes, coronary heart illness, or in case you are in a stage of life the place you’re pregnant or breast-feeding, fasting will not be match for you.
Keep in mind, fasting is probably not best for you for various causes, and that’s OK too. If you end up experiencing damaging unintended effects, open up your consuming window to enhance your signs.
What to Eat Throughout Intermittent Fasting
Whereas intermittent fasting focuses on once you eat, what you eat and drink issues.

Nutrient-Dense Meals
Intermittent fasting might not let you know what to eat, however diet issues for any eating regimen plan.
Listed here are just a few key nutritious meals to eat as a part of a balanced eating regimen whereas fasting.
- Lean proteins: Hen, fish, turkey, eggs, tofu, yogurt, and legumes. (18)
- Entire grains: Quinoa, brown rice, oats, and whole-wheat merchandise. (18)
- Wholesome fat: Avocados, nuts, seeds, low fats cheese, and olive oil. (18)
- Fiber-rich greens and fruits: Set a purpose to incorporate 5 totally different colours in your day to eat extra fruits and veggies. (18)
Monitoring your meals and snacks in addition to your macros within the MyFitnessPal app might help maintain you on monitor to fulfill your diet objectives.
Hydration and Electrolytes
Dehydration is a doubtlessly severe facet impact of fasting. Simply since you’re not consuming doesn’t imply it’s best to cease consuming water. Water, tea, espresso, and different no-calorie drinks won’t break a quick, however they are going to assist maintain you hydrated. (19)
Additionally, sustaining electrolyte steadiness is necessary, particularly throughout prolonged fasts. Contemplate including electrolyte-rich meals throughout your consuming home windows, resembling bananas, avocados, and leafy greens. (20)
Maintain monitor of how a lot water you’re consuming within the MyFitnessPal app to be sure to keep hydrated.
Combining Intermittent Fasting with Different Diets
Combining fasting with particular diets might help you maximize advantages like fats loss, muscle upkeep, and improved total well being.
Keto and Intermittent Fasting
The ketogenic eating regimen and intermittent fasting each encourage the physique to enter ketosis, a metabolic state the place fats is used as the first vitality supply. When fasting, the physique depletes its glycogen shops and switches to burning fats, which aligns with the objectives of keto. (21)
This mixture might speed up fats burning and assist weight reduction. Nonetheless, transitioning into ketosis could also be tougher throughout fasting, so it’s necessary to make sure your physique is ready for each dietary approaches.
In case you discover this strategy too restrictive or excessive, add in high-fiber carbohydrates and be extra versatile along with your fasting window. (22)
Intermittent Fasting and Plant-Primarily based Diets
Pairing intermittent fasting with a plant-based eating regimen presents a nutrient-dense strategy whereas specializing in entire meals. Plant-based diets are naturally excessive in fiber, which promotes satiety and helps digestion throughout consuming home windows. (23)
When mixed with intermittent fasting, this consuming sample might enhance intestine well being, assist management blood sugar ranges, and supply important vitamins like nutritional vitamins and minerals.
Make certain your plant-based meals are wealthy in protein from sources like beans, legumes, and tofu to keep up muscle mass whereas fasting.
Low-Carb Diets and Fasting
A low carb eating regimen usually retains carbs low whereas specializing in protein, wholesome fats, and decrease carb fruits and veggies.
Decrease carb diets can assist wholesome blood sugar ranges, and when mixed with fasting may velocity up weight reduction. (24) Nonetheless, many individuals discover this mix difficult to stay to long run.
Intermittent Fasting for Totally different Targets
Intermittent fasting will be tailored to suit numerous well being and wellness objectives. Whether or not you’re seeking to drop some pounds, construct muscle, or enhance psychological readability, fasting is usually a versatile device.
Intermittent Fasting for Weight Loss
Intermittent fasting reduces the variety of hours obtainable for consuming, so it tends to scale back calorie consumption and create a calorie deficit. To remain on monitor, plan nutrient-dense meals throughout consuming home windows and create a routine that helps you keep away from overeating, which is usually a frequent pitfall for folk new to fasting. (1)
Intermittent Fasting for Muscle Achieve
Intermittent can assist muscle mass when mixed with the correct diet and train routine. (25)
An important diet components for growing muscle are consuming sufficient energy and protein consumption. Power coaching throughout your consuming window will even assist protect muscle mass, whereas fasting can enhance development hormone manufacturing, which helps muscle upkeep. (25)
Intermittent Fasting for Improved Psychological Readability
Some folks report improved psychological readability and focus when fasting. Intermittent fasting may also assist cut back mind fog by stabilizing blood sugar ranges, main to raised focus. (14) Moreover, fasting encourages the manufacturing of brain-derived neurotrophic issue (BDNF), a protein linked to cognitive enchancment and neuroprotection. (14)
Frequent Challenges and How you can Overcome Them
Intermittent fasting can current challenges, particularly when first beginning out. Fortuitously, there are methods to beat frequent obstacles.
Coping with Starvation and Cravings
Managing starvation is probably going the highest wrestle for individuals who start intermittent fasting. To fight this, concentrate on consuming excessive protein and fiber-rich meals throughout your consuming home windows, as they are going to enable you to really feel full longer. (26)
Ingesting water, natural teas, or black espresso throughout fasting hours can even assist suppress starvation and stop dehydration. And lastly, consuming sufficient complete energy throughout your consuming window will assist cut back signs of starvation and cravings. (26)
Staying In line with Your Fasting Schedule
Sustaining consistency is essential to success with intermittent fasting. To assist with this, create a fasting schedule that aligns along with your day by day routine.
Use instruments just like the MyFitnessPal Intermittent Fasting Timer to log your fasting hours and monitor your progress. Moreover, being versatile along with your fasting window on busy or social days might help you keep constant with out feeling restricted.
Intermittent Fasting and Social Conditions
Fasting will be difficult in social conditions, resembling eating out or attending occasions. To handle this, take into account shifting your fasting window to accommodate your plans. As an illustration, you probably have a dinner occasion, begin your fasting interval later within the day. Go for lighter meals earlier than or after the occasion, and keep conscious of your total calorie consumption.
Success Tales & Testimonials
Two of my private shoppers have efficiently built-in intermittent fasting into their lives and achieved spectacular outcomes. (I’ve modified their names for his or her privateness.)
Jane, a 55-year-old counselor and social employee, used intermittent fasting to lose 20 kilos in about six months. She credit her success to having a listing of meals she ate virtually day-after-day that stored her full and prevented sugar cravings at evening whereas fasting.
Equally, Mark, a 40-year-old lawyer, observed improved psychological readability and sustained vitality after incorporating intermittent fasting into his routine. He loved not having to consider meals on busy days on the workplace, and will concentrate on cooking a balanced meal at residence.
Regularly Requested Questions About Intermittent Fasting
Begin with a brief fasting window, resembling 10-12 hours, and step by step enhance it as your physique adapts. Keep hydrated and concentrate on balanced meals throughout consuming home windows.
The 16/8 technique is a good place to begin for freshmen, although we suggest you alter the fasting and consuming home windows based mostly in your life-style.
Intermittent fasting works by limiting the hours throughout which you eat, selling fats burning and doubtlessly making a calorie deficit.
Each choices have advantages; a 12-hour fasting window is extra versatile whereas a 16-hour fasting window tends to advertise extra fats burning because of the prolonged fasting interval.
Sure, black espresso is allowed throughout fasting intervals as it’s low in energy and gained’t break your quick.
The Backside Line
Intermittent fasting presents quite a few potential advantages, from weight reduction and metabolic well being to improved mind perform and mobile restore. Nonetheless, it may not be the correct diet strategy for you.
It’s necessary to think about the potential dangers, particularly you probably have sure medical circumstances, and cease fasting when you expertise unmanageable starvation or cravings.
At MyFitnessPal, we don’t endorse one sort of eating regimen, quite, we assist every particular person discovering what works for you.
How MyFitnessPal Can Assist
Whether or not you’ve been intermittent fasting already, or are merely curious in regards to the consuming sample’s potential well being advantages, MyFitnessPal’s Premium Intermittent Fasting Tracker characteristic might help!
You may select one in every of 3 fasting patterns relying in your life-style or objectives:
- 12:12 — 12-hour quick, 12-hour consuming window. This sample is good for syncing meals to your circadian rhythm.
- 14:10 — 14-hour quick, 10-hour consuming window. This sample encourages common meals and fewer snacking all through the day.
- 16:8 – 16-hour quick, 8-hour consuming window. This sample usually includes skipping both a.m. or p.m. consuming instances.
Then, you possibly can monitor day by day fasting intervals in your diary—proper alongside meals, water, and train.
The submit The Science Behind Intermittent Fasting: Benefits and Risks Explained appeared first on MyFitnessPal Blog.