Intermittent fasting has gone from niche fitness strategy to mainstream wellness trend, and at this point, you probably know someone who skips breakfast and calls it “biohacking.”
But fasting is not new. Humans have been fasting for centuries for religious, cultural and practical reasons, long before anyone was tracking an eating window on an app.
Fasting has long been part of religious traditions, including Ramadan, and it also played a role in how humans ate before food was available 24/7. Back when we were hunter-gatherers, eating depended on what could be found, hunted or gathered that day.
Often, the earlier part of the day may have been spent looking for food rather than sitting down to a neatly plated breakfast. Nuts, seeds, fruit, vegetables and wild meats would then be eaten later, when the day’s work was done and it was safer to stay around camp.
Any morning meal would likely have been leftovers from the night before, assuming there were leftovers at all. Not exactly a drive-thru breakfast sandwich and a latte situation.
This is where intermittent fasting gets some of its appeal. The idea is that going longer stretches without food may fit more naturally with how humans once lived, compared with today’s constant grazing, snacking and “just one more bite” culture.
That being said, our ancestors also didn’t have refrigerators, grocery stores or modern medicine. I always think it is worth being careful when we romanticize the caveman lifestyle, because I, for one, am not looking to give up indoor plumbing or coffee.
This history does challenge the traditional belief that breakfast must be eaten first thing in the morning to be healthy. You may have heard the old phrase:
“Eat breakfast like a king, lunch like a prince and dinner like a pauper.”
Yet the word breakfast simply means to break the fast. That meal does not have to happen at 7 a.m. just because a cereal commercial said so.
The “early morning meal” as we know it is a more recent development in food culture. Breakfast became more popular in the 17th century, when wealthier households created breakfast rooms as another lovely way to show everyone they were wealthy.
As working patterns changed, people doing long hours of manual labor often needed something to eat before heading out for the day. Later, John Harvey Kellogg helped push breakfast into the mainstream in the early 20th century with cornflakes and the larger rise of convenient breakfast foods.
As nations changed through the first and second world wars, sliced bread, toasters, sweetened cereals and instant coffee became more common. And just like that, breakfast became not only a meal, but an entire industry.
The Romans were famously known for consuming a single meal around noon and little else afterward. This does not mean we all need to eat like Romans, but it does show that three meals plus snacks is not the only way humans have ever eaten.
Now, none of this means breakfast is bad. It simply means skipping it is not automatically bad either.
What matters more is your total diet quality, your energy needs, your medical history and whether a fasting schedule helps you eat in a way that is realistic. That last part matters more than people give it credit for.
There are two general states your body moves between: the fed state and the fasted state.
In the fed state, your body is digesting food, absorbing nutrients and storing or using energy from carbohydrates, fats and protein. This is often described as an anabolic state, which means the body is building and storing.
After several hours, depending on what and how much you ate, your body moves into the post-absorptive state. This simply means your body is no longer actively digesting and absorbing that meal.
Eventually, you enter the fasted state, where your body relies more on stored energy. Insulin levels tend to fall, fat oxidation may increase and the body begins leaning more on stored fuel between meals.
This sounds very exciting, and honestly, it can be useful. But it is also where people sometimes start making fasting sound more magical than it is.
Intermittent fasting can help some people lose weight because it often reduces the total number of hours available to eat. Fewer eating hours can mean fewer calories, especially for people who tend to snack at night or graze throughout the day.
Research does suggest that time-restricted eating may produce weight loss and improvements in some metabolic markers for certain people. However, in a 2022 study in The New England Journal of Medicine, time-restricted eating was not more effective for weight loss than daily calorie restriction when calories were similar.
That is an important point. The fasting window can be helpful, but it does not cancel out what happens during the eating window.
In other words, a 16-hour fast followed by a large pizza, three cookies and “because I fasted” logic may not work out the way you hoped. I wish it did, truly.
Another possible benefit is simplicity. Many people enjoy not having to think about breakfast, snacks and food decisions all morning.
There can also be a feeling of mental clarity or alertness during the fasting portion of the day. Some of that may be physiological, and some of it may simply be the result of not feeling overly full or sluggish from constant snacking.
Fasting may also make meals feel more satisfying. After going several hours without eating, food can feel more intentional and enjoyable.
That may be one of the most underrated benefits. Becoming aware of actual hunger and fullness cues can be helpful, especially if you are used to eating because the clock, your inbox or your emotions told you to.
There is also ongoing interest in fasting, calorie restriction, longevity and cell repair. As noted by the National Institute on Aging, animal research is promising, but human research is still evolving and we do not yet have all the answers.
That is the less glamorous but more honest answer. Fasting may be helpful, but it is not a guaranteed anti-aging plan wrapped in a smaller eating window.
Also worth noting: intermittent fasting is not right for everyone. People who are pregnant or breastfeeding, have a history of eating disorders, take medications that require food, have diabetes or blood sugar concerns, or are underweight should speak with a qualified health professional before trying it.
I would also be cautious for anyone who finds the fasting window leads to binge eating later. A diet strategy is only successful if it improves your health and your relationship with food.
1. 5:2 Fasting – The 5:2 method is less of a true daily fast and more of a weekly calorie-cycling approach.
You eat normally five days of the week and then limit calories on two non-consecutive days. Traditionally, those two lower-calorie days are around 500 calories for women and 600 calories for men, though individual needs vary.
This style became more popular after British broadcaster Michael Mosley explored fasting in a BBC documentary. It can work well for some people, but the low-calorie days are not exactly a picnic.
My main issue with this method is that very low-calorie days can trigger intense hunger, irritability and overeating the next day for some people. Not everyone becomes their best self on 500 calories, and by “not everyone,” I mean most of us.
2. The Lean Gains Method – This is also known as the 16/8 method because it includes a 16-hour fasting window and an 8-hour eating window.
The method was popularized by Martin Berkhan on his site Lean Gains. Many people find this the easiest version because it usually means skipping breakfast or eating a later first meal.
For example, you may stop eating at 8 p.m. and eat again at noon the next day. The exact timing can be adjusted based on your schedule, workouts, family meals and, frankly, real life.
This is probably the most popular style of intermittent fasting because it can feel less extreme than full-day fasts. It also keeps the structure the same most days, which can make it easier to stick to.
That said, the quality of the food still matters. Eight hours is plenty of time to eat a balanced diet, but it is also plenty of time to turn the eating window into a snack festival.
3. Eat. Stop. Eat. – This is a more intense fasting approach from Brad Pilon, author of the book by the same name.
It generally involves one or two 24-hour fasts per week. For example, you might finish dinner one night and not eat again until dinner the next night.
This method can reduce weekly calorie intake, but it can be mentally and physically challenging. Social events, family meals and workouts can also make a full-day fast harder to maintain.
I would not start here if you are new to fasting. There is no prize for choosing the hardest version first.
4. Juice Fasting – Juice fasting is often called fasting, but it is not really fasting in the traditional sense.
You are still consuming calories, mostly from carbohydrates and natural sugars. You are just drinking them instead of eating whole food.
I would not recommend a juice fast as a long-term strategy. It is very low in protein, usually low in fat and often low in fiber, which are three things that help with fullness, blood sugar control and overall nutrition.
Plus, when fruits and vegetables are juiced, much of the skin and pulp is removed. That means you may lose some of the fiber and beneficial plant compounds that make produce so healthy in the first place.
Eating the whole apple is usually going to serve you better than drinking four apples in juice form. Less glamorous, maybe, but your blood sugar may appreciate it.
5. The Warrior Diet – This method was based on a book that helped bring daily fasting into popular fitness culture.
The idea is to under-eat during the day with small amounts of foods such as raw vegetables, fruit, eggs, protein or nuts, and then eat one large meal at night. It is not a complete fast, but more of an under-eating and over-eating pattern.
The evening meal is often described as a feast, with recommendations around eating vegetables first, then protein, then carbohydrates and fats. The goal is to stop when satisfied rather than stuffed.
This can work for some people with hectic daytime schedules. But for others, saving most calories for night can lead to overeating, poor sleep or feeling uncomfortably full before bed.
Also, any plan that tells you to ignore thirst or avoid water around meals makes me pause. Hydration does not need to be complicated.
6. Feast/Fast Approaches – Some fat-loss programs use a “cheat day” followed by a longer fasting window.
The idea is that you enjoy a higher-calorie day, often around a social event, and then fast the following day or fast until noon the day after. In theory, the longer fasting period balances out the higher-calorie day.
This may appeal to people who like clear rules, but it can also create an uncomfortable restrict-and-overeat cycle. For many people, calling one day a “cheat day” can lead to eating far past what feels good simply because the rules said this was the day to do it.
I am never a huge fan of language that makes food feel like a moral test. Food is food, not a character assessment.
For most people, a more sustainable version is simply planning for higher-calorie meals occasionally and then returning to regular balanced eating at the next meal. No punishment fast required.
Short-term fasting does not automatically shut down your metabolism. Earlier research found a lowered metabolic rate after a longer fast of around 60 hours, while other studies have shown that very short-term fasting may temporarily increase metabolic rate.
That does not mean longer fasting is better. It simply means that skipping breakfast or eating in a shorter window is not the same thing as famine.
In reality, protein digestion and absorption take time. Eating enough total protein across the day matters far more than eating it every two hours on the dot.
For people who strength train, getting enough protein and doing resistance exercise are the big rocks. The International Society of Sports Nutrition notes that protein timing can be useful, but total daily protein intake remains one of the most important factors for muscle maintenance and growth.
That said, extremely long fasts, very low calories or poor protein intake can absolutely put lean mass at risk. Fasting is not a free pass to under-eat protein and hope your muscles understand.
Some people feel better eating breakfast, especially if they train early, have physically demanding jobs or find that skipping it leads to overeating later. Others feel perfectly fine delaying their first meal.
Body composition comes down to overall intake, food quality, activity, sleep, stress and consistency. A missed morning meal does not automatically cause fat gain.
Lower-intensity workouts, walks and some strength sessions may feel fine in a fasted state. Longer endurance workouts, high-intensity intervals or heavy lifting may be better with some food beforehand.
This is one of those areas where personal response matters. Your workout performance is allowed to be the deciding factor, not someone’s comment section.
A 2020 randomized clinical trial in JAMA Internal Medicine found that time-restricted eating did not produce significantly more weight loss than consistent meal timing, and there were concerns about lean mass loss in that study. That does not mean fasting is bad, but it does mean strength training, adequate protein and enough total calories matter.
1. Black Coffee – Coffee contains caffeine, which can provide energy to the body and may help with alertness.
Black coffee is one of the easiest fasting-friendly drinks because it has very few calories. Adding sugar, creamers or a large amount of milk turns it into more of a snack than a fasting beverage.
Some people allow a splash of milk or anything under about 50 calories during the fasting window. Just know that this is more of a practical rule than a strict scientific line in the sand.
Other options include plain black tea, green tea, white tea, matcha or yerba mate. Just be mindful of caffeine late in the day, because sleep is still part of health, even when fasting is trendy.
2. Sparkling Water – Sparkling water can make fasting feel a little less boring.
There is something about bubbles that makes a drink feel more exciting, even when it is just water wearing a fun outfit. Add lemon, lime, cucumber or mint if you need a little flavor.
Hydration is especially important during a fasting window because some people mistake thirst for hunger. A glass of water will not fix true hunger forever, but it can help you figure out what your body is actually asking for.
3. Be Smart About Protein Around Workouts – The old advice was often to take 5 to 10 grams of BCAAs before fasted training.
BCAAs are branched-chain amino acids, including leucine, isoleucine and valine. Leucine plays a role in muscle protein synthesis, which is one reason BCAA supplements became so popular.
However, BCAAs do contain amino acids, which means they are not truly “nothing” during a fast. Also, if you are already eating enough high-quality protein during your eating window, extra BCAAs may not add much.
For most people, a balanced meal with protein after training will do the job. Those doing hard fasted workouts may feel better with essential amino acids, whey protein or a regular pre-workout snack, but that technically ends the fast.
And yes, flavored powders usually taste better than unflavored ones. Some unflavored amino acid powders taste like punishment, and I see no reason to suffer unnecessarily.
Overall, intermittent fasting can be a useful way to reduce your calories and simplify eating for part of the day. It may help with weight management, blood sugar control and appetite awareness for some people.
But it is not magic. Your overall calorie intake, food quality, protein, fiber, sleep, exercise and consistency still matter.
A healthy fasting plan should still include plenty of fruits, vegetables, whole grains, legumes, lean proteins, healthy fats and enough calories to support your body. Fasting while eating a low-quality diet is still a low-quality diet.
Be especially careful if fasting makes you feel anxious around food, leads to binge eating, disrupts your sleep or affects your menstrual cycle. Women may be more sensitive to aggressive fasting approaches, and anyone with medical conditions should check with a doctor or registered dietitian before starting.
Pick a method that fits your lifestyle, not the one that sounds most impressive. Try it for a week or two, pay attention to your energy, mood, digestion, workouts and hunger, and keep what works.
At the end of the day, the best eating pattern is one that supports your health and still allows you to live your life. I call that much more useful than forcing yourself into a fasting window just because the internet told you to.
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