What Is Intermittent Fasting
Many diets focus on what to eat, but intermittent fasting is all about when you eat.
With intermittent fasting, you only eat during a specific time. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help your body burn fat. And scientific evidence points to some health benefits, as well.
Johns Hopkins neuroscientist , has studied intermittent fasting for 25 years. He says that our bodies have evolved to be able to go without food for many hours, or even several days or longer. In prehistoric times, before humans learned to farm, they were hunters and gatherers who evolved to survive and thrive for long periods without eating. They had to: It took a lot of time and energy to hunt game and gather nuts and berries.
Even 50 years ago, it was easier to maintain a healthy weight. Johns Hopkins dietitian Christie Williams, M.S., R.D.N., explains: There were no computers, and TV shows turned off at 11 p.m. people stopped eating because they went to bed. Portions were much smaller. More people worked and played outside and, in general, got more exercise.
Nowadays, TV, the internet and other entertainment are available 24/7. We stay awake for longer hours to catch our favorite shows, play games and chat online. Were sitting and snacking all day and most of the night.
Fast For 12 Hours A Day
The rules for this diet are simple. A person needs to decide on and adhere to a 12-hour fasting window every day.
According to some researchers, fasting for 1016 hours can cause the body to turn its fat stores into energy, which releases ketones into the bloodstream. This should encourage weight loss.
This type of intermittent fasting plan may be a good option for beginners. This is because the fasting window is relatively small, much of the fasting occurs during sleep, and the person can consume the same number of calories each day.
The easiest way to do the 12-hour fast is to include the period of sleep in the fasting window.
For example, a person could choose to fast between 7 p.m. and 7 a.m. They would need to finish their dinner before 7 p.m. and wait until 7 a.m. to eat breakfast but would be asleep for much of the time in between.
How The 16/8 Intermittent Fasting Diet Works
Like exercise, restricting calories is a helpful metabolic stressor. Eating within a certain time frame pushes your body in a different metabolic direction than if you were eating all the time.
Intermittent fasting can cause autophagy, which is a crucial defense mechanism against malignancy, infection, and neurodegenerative diseases. Its basically your bodys way of cleaning out cells that arent performing at their best.
Research finds short-term fasting is an effective way of starting neuronal autophagy , therefore protecting your brain against neurodegenerative diseases.
Intermittent fasting also triggers a beneficial metabolic reaction that includes:
- A decrease in inflammatory markers
- Reduced blood glucose levels and insulin
- An increase in the neurotrophin BDNF
These are powerful changes that can lead to several health improvements.
Take the keto quiz
You May Like: When You Are Fasting Can You Drink Water
Concerns About 16/8 Fasting
Intermittent fasting, especially the 16/8 approach, is completely safe and beneficial. Contrary to common belief, moderate calorie restriction is a healthy practice that improves your metabolic health.
However, if youre using it to get into ketosis, it might not be enough to get you there. If your fasting goal is to enter ketosis, you also need to follow a keto diet.
Best Hours For Intermittent Fasting 16/8
When choosing which 8 hours of the day will make up your eating window, really considering your daily routine and schedule will be key. Most often, people following 16/8 intermittent fasting will choose to skip breakfast and eat in a window from roughly 11 a.m.-7 p.m. or 12 p.m.- 8 p.m., with those later hours allowing for flexibility for after work get-togethers and later dinners with friends and familythis option is also great for late-risers. If you choose to allow for coffee or tea in your plan, you can ease into your day with a cup and then begin your eating window with lunch or a late-morning snack.
In our current pandemic climate, however, you probably dont have any after-work gatherings with friends on your agendain which case you may want to try moving your last meal earlier in the day so you can allow for an earlier breakfast. Intermittent fasting allows for flexibility, and the best schedule can only be determined by what you will be able to stick with .
You May Like: What Can I Add To My Coffee While Intermittent Fasting
Intermittent Fasting Why Meal Timing Matters
Simply put, intermittent fasting is the dietary strategy of restricting your food consumption to a specific window of time. For example, one of the most common intermittent fasting approaches is fasting during an 18-hour window of time and eating during the 6-hour window of time that is left in the day.
Lets say your last meal was at 6 pm last night and you ate nothing else after that. To implement an intermittent fast, simply restrict eating until 12 pm the next afternoon . To do this every day, only eat between 12 pm and 6 pm and fast for the remainder of the day.
There are many different variations of intermittent fasting as well. Dr. Dom DAgostino, a well-known ketogenic diet researcher, suggests doing a longer intermittent fast for 3 days, 3 times a year. This means not eating for 3 days, and eating normally until the next fast.
Another way to try fasting for yourself is by incorporating intermittent fasts of 16 or more hours per day into your lifestyle. This is a much more accessible strategy that allows you to experience many of the benefits of taking a short break from calories.
Despite the simplicity of this concept, it may not be readily apparent how beneficial intermittent fasting can be for you, especially if you are already benefiting from the ketogenic diet.
Intermittent Fasting Can Be Hard But Maybe It Doesnt Have To Be
Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though people struggled with the fasting days. So, its very reasonable to choose a reduced calorie plant-based, Mediterranean-style diet. But research suggests that not all IF approaches are the same, and some IF diets are indeed effective and sustainable, especially when combined with a nutritious plant-based diet.
We have evolved to be in sync with the day/night cycle, i.e., a circadian rhythm. Our metabolism has adapted to daytime food, nighttime sleep. Nighttime eating is well associated with a higher risk of obesity, as well as diabetes.
Based on this, researchers from the University of Alabama conducted a study with a small group of obese men with prediabetes. They compared a form of intermittent fasting called “early time-restricted feeding,” where all meals were fit into an early eight-hour period of the day , or spread out over 12 hours . Both groups maintained their weight but after five weeks, the eight-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure. The best part? The eight-hours group also had significantly decreased appetite. They werent starving.
Just changing the timing of meals, by eating earlier in the day and extending the overnight fast, significantly benefited metabolism even in people who didnt lose a single pound.
Read Also: Is Fasting Good For Your Health
What Is The Ideal Time For Fasting
Well, this is going to depend on your lifestyle.
What hours do you work? What time do you wake up?
What time do you go to bed?
If you want to have success with intermittent fasting these are the questions you need to start asking yourself. Your answers will vary from the next person. The ideal time for fasting is really going to be determined by your schedule.
Here is an example: When I was following the 16:8 schedule I was waking up at 6 am, started working at 8 am and then my first meal was at Noon. When I got home around 6 pm, Id eat dinner and have a light snack at 7:30 by 8 pm I was done eating until Noon the next day.
I, of course, was also following a ketogenic lifestyle so my total carb intake was anywhere between 15 20 carbs per day . This allowed me to get the most out of intermittent fasting.
If you want to get started on Keto check out my FREE KETO EDITION: EAT THIS, NOT THAT. This is a great place to start and will show you all the foods that are Keto approved. As well as, foods you should avoid.
Want to know what your Macros are? Download the CARB MANAGER APP for FREE.
Like I said before, its whatever makes the most sense for your lifestyle. Whatever time frame is easiest for you is what you should aim for and this will allow you to be consistent!
Fasting For 2 Days A Week
People following the 5:2 diet eat standard amounts of healthful food for 5 days and reduce calorie intake on the other 2 days.
During the 2 fasting days, men generally consume 600 calories and women 500 calories.
Typically, people separate their fasting days in the week. For example, they may fast on a Monday and Thursday and eat normally on the other days. There should be at least 1 non-fasting day between fasting days.
There is limited research on the 5:2 diet, which is also known as the Fast diet. A involving 107 overweight or obese women found that restricting calories twice weekly and continuous calorie restriction both led to similar weight loss.
The study also found that this diet reduced insulin levels and improved insulin sensitivity among participants.
A small-scale study looked at the effects of this fasting style in 23 overweight women. Over the course of one menstrual cycle, the women lost 4.8 percent of their body weight and 8.0 percent of their total body fat. However, these measurements returned to normal for most of the women after 5 days of normal eating.
Read Also: What Is 18 6 Intermittent Fasting
How To Get Started
16/8 intermittent fasting is simple, safe and sustainable.
To get started, begin by picking an eight-hour window and limit your food intake to that time span.
Many people prefer to eat between noon and 8 p.m., as this means youll only need to fast overnight and skip breakfast but can still eat a balanced lunch and dinner, along with a few snacks throughout the day.
Others opt to eat between 9 a.m. and 5 p.m., which allows plenty of time for a healthy breakfast around 9 a.m., a normal lunch around noon and a light early dinner or snack around 4 p.m. before starting your fast.
However, you can experiment and pick the time frame that best fits your schedule.
Additionally, to maximize the potential health benefits of your diet, its important to stick to nutritious whole foods and beverages during your eating periods.
Filling up on nutrient-rich foods can help round out your diet and allow you to reap the rewards that this regimen has to offer.
Try balancing each meal with a good variety of healthy whole foods, such as:
- Fruits: Apples, bananas, berries, oranges, peaches, pears, etc.
- Veggies: Broccoli, cauliflower, cucumbers, leafy greens, tomatoes, etc.
- Whole grains: Quinoa, rice, oats, barley, buckwheat, etc.
- Healthy fats: Olive oil, avocados and coconut oil
- Meat, poultry, fish, legumes, eggs, nuts, seeds, etc.
Drinking calorie-free beverages like water and unsweetened tea and coffee, even while fasting, can also help control your appetite while keeping you hydrated.
What Is 16/8 Intermittent Fasting
The practice of 16/8 intermittent fasting involves limiting your intake of foods and calorie-containing beverages to a set window of 8 hours per day. You abstain from food for the remaining 16 hours, though youre still allowed to drink water and other no-calorie beverages, like plain coffee or tea.
You can repeat this cycle as frequently as youd like from just once or twice per week to every day, depending on your preference.
The popularity of this fasting method has grown widely among those looking to lose weight and burn fat. 16/8 intermittent fasting is also believed to improve blood sugar control and enhance longevity.
While other diets often set strict rules, 16/8 intermittent fasting is easy to follow and may provide measurable results with minimal disruption to your diet. Its generally considered less restrictive and more flexible than many other diets and works with most lifestyles.
With 16/8 intermittent fasting, you restrict your food intake to an 8-hour window and fast for the remaining 16 hours. This practice may support weight loss, improve blood sugar, and increase longevity.
It is simple, safe, and sustainable to do 16/8 intermittent fasting.
Also Check: Is Intermitten Fasting Good For You
Protect Cognitive Function In Older Age
Several different studies suggest that fasting helps to improve sleep while offering protection against cancer recurrence as well as reducing the bad cholesterol and lowering the blood pressure. A recent study conducted by the National Institute on Ageing in Baltimore has demonstrated that periodic calorie restriction helps to protect the cognitive function in older age. The researchers believe that the nerve cells are protected and new brain cells thrive, which then trick the older brain into acting younger.
Intermittent Fasting Is Not A Magic Pill
The bottom line with IF? Although the jury is still out and long-term effects are still being studied, its crucial to eat a healthy, well-balanced diet while following IF.
You cant eat junk food and excessive calories on non-fasting days and expect to lose weight, says Taylor.
Recommended Reading: Does Fasting Make You Skinny
Youre Not Playing Around With Your Timeframe
One friend raves about eating only within an eight-hour timeframe daily, but another friend eats in a 12-hour timeframe but fasts for one entire day per weeka strategy known as 7:1and yet another says 10-hour time blocks are the way to go.
Which are you supposed to choose? The expert advice is: All of them.
It takes time to find out what works best for you, and that involves different approaches with the understanding that if youre not seeing benefits, you likely need another strategy,Luiza Petre, M.D., a cardiologist who practices intermittent fasting herselfas well as advises the strategy for patientstells Runners World.
The easiest way to start is with the most common variation first, she suggested, which is an 8-hour block, followed by fasting time that includes sleep. For example, breakfast at 9 a.m. and dinner at 5 p.m. and then not eating again until the next morning.
When youre getting started, its much better to see this as a long-term strategy and experiment with different schedules, rather than think you need to stick to one specific schedule because thats what worked for a friend or family member, Petre says.
/9exercising In The Fasted State
It is a common belief that one should abstain from any kind of stern physical activity when fasting. But this concept is not completely true. You can easily exercise in the fastest states. It all depends on your capacity and energy level. We would not suggest involving any kind of stern activity. Light walking, jogging, bodyweight exercises are much-preferred options. You should plan your workout session before breaking your fast. Remember it is always best to listen to your body. If you feel like you can perform exercises, only then attempt it else let it be. Do not forget to stay hydrated all the time to make up for the fluid loss.
Read Also: What Can I Eat When Fasting
What Is Intermittent Fasting 16/8
Intermittent fasting , also known as time-restricted feeding, means eating within a specific daily window of time and fasting outside of that window .
There are several different types of intermittent fasting, but the 16/8 method is the most popular because its the easiest.
Doing an 16/8 intermittent fast means that you fast for 16 hours and eat only within an eight-hour window throughout the day, such as from noon to 8 p.m.
The easiest approach is to skip breakfast and have your first meal later in the day. For example, if you finish dinner by 8 p.m., you wouldnt eat again until midday the next day.
Keep in mind 16/8 intermittent fasting is only one approach. The windows can vary based on what works for you. While some people might only eat within the same eight hours a day, others might only eat within a six-hour window or four-hour window .
What Exactly Is Intermittent Fasting
Intermittent Fasting is nothing more than timing up your food at certain times throughout the day and basically having a window in which you eat. That window can be anywhere between four to eight hours, and you close that window or widen it. You typically put that window in the last third of the day which is when you tend to be more insulin sensitive naturally.
Lets talk about that window for example, instead of eating between 7AM and 8PM, thats a thirteen hour window, were taking that and closing it down maybe to eight, or five, or four hours.
Read Also: Does Fasting Slow Your Metabolism
Hormonal Changes And Menstrual Cycles
Some animal research suggests that intermittent fasting may lead to hormonal changes and undereating. In people with ovaries, these changes may negatively affect menstrual cycles and fertility .
However, most studies are old and have been conducted in animals. Human studies are needed to fully understand how intermittent fasting may affect reproductive health.
Furthermore, postmenopausal individuals may experience different effects from intermittent fasting. Menopause causes changes that can decrease insulin sensitivity and lead to weight gain, and intermittent fasting may help improve these outcomes .
Restricting daily food intake to a particular time window may cause increased food intake and weight gain, as well as short-term hunger and weakness. Older animal studies indicate that intermittent fasting may interfere with fertility.