The Complete Guide to 18:6 Intermittent Fasting Schedule
By: Taylor Ford
Executive Editor
Summary:
- 18:6 intermittent fasting is when you abstain from eating for 18 hours and eat all your meals in a 6-hour window.
- Benefits: increased energy, lower blood sugar, potential weight loss.
- Our conclusion: Short term diets are not a long term solution, but the nutrition & lifestyle choices made while 18:6 intermittent fasting could be beneficial if added to your consistent routine.
A recent study found that over the course of a year people can lose about 5% of their body weight by staying consistent with intermittent fasting. This article is a guide to the most popular form of fasting, 18/6.
During prehistoric times, before humans understood planting crops and farming, they would hunt and gather their food. Johns Hopkin's, Mark Mattson, is a neuroscientist who has studied intermittent fasting for over 25 years, says our bodies evolved and the benefits of going without food can still be seen today.
He calls it the metabolic switch, after hours without food your body runs through it stores of sugar and begins burning fat. This process is called ketosis.
What our ancestors called a "bad hunt" we now happily participate in and call it "intermittent fasting."
WHAT IS 18/6 INTERMITTENT FASTING?
Intermittent fasting is where you have a set window during the day when you can eat. The rest of the day, you abstain from eating, keeping your body in a fasting state.
18/6 intermittent fasting is when you abstain from eating for 18 hours and eat all your meals in a 6-hour window.
You should choose your time restricted eating window based on your lifestyle and what works best for you. You could skip breakfast, start your first meal at 12:30 pm and end your time restricted eating window at 6:30 pm to eat dinner. Others may choose to start their first meal later in the day to have a later dinner. You may have to try out different schedules to see what works best for your lifestyle.
How does IF work? I think Gin Stephens in her New York Times best selling book "Fast. Feast. Repeat." said it best:
"Insulin is the key to whether your body is in fat-storing mode or fat-burning mode, and fasting puts you solidly into the fat-burning side of the equation … which is just what we want!"
Summary
- By fasting for 18 hours and consuming your calories within a 6 hour window you can put your body into ketosis.
HOW IS THE 18:6 FASTING SCHEDULE DIFFERENT FROM OTHERS?
18:6 is known as one of the more difficult IF schedules. Keeping your body in a fasting state for 18 hours isn't something you jump right into. If you have tried 12:12 or 16:8 and didn't see results, or if you want to kick your weight loss up a notch, 18:6 might be for you.
Some people do alternate day fasting periods, which are a bit easier and potentially a starting point if you are interested in trying 18:6. Alternate-day fasting typically involves fasting every other day and restricting your calories to 25% of your energy requirements. For example:
Day 1: Eat normally
Day 2: 25% (500 calories)
Day 3: Eat Normally
As for the success of ADF, some studies have shown a potential weight loss between 3-8% within 12 weeks.
Summary
- Other methods of fasting include changing out the fasting period or alternating your fasting days.
BENEFITS OF 18:6 INTERMITTENT FASTING
18 hours without food can be challenging, but many people experience better digestion with the 6-hour eating window. With a goal of 18 hours, you may notice reduced bloating and indigestion that occurs when you eat too frequently.
Of course, the number one benefit of IF for most people is weight loss. Here are some added benefits to 18:6 IF:
Weight loss
One of the primary benefits of 18:6 intermittent fasting is weight loss. Your body goes into ketosis as your blood levels of insulin drop.
Also, by limiting your calorie intake and the time frame in which you consume your calories, you may be able to create a calorie deficit without feeling deprived or hungry. Studies have shown that intermittent fasting can help you lose weight and reduce body fat, while maintaining muscle mass, leading to more muscle growth a healthier overall body composition.
How much weight loss depends on a lot of factors, it especially helps you lose weight if you combine fasting with a healthy, balanced diet and an exercise plan. One study found a 3-8% weight loss over 3-24 weeks, and another found a reduction in waist circumference of 4-7% between 6-24 weeks.
May help reduce inflammation
Inflammation is the root cause of many chronic diseases, including heart disease, arthritis, and even cancer. By reducing inflammation in the body, 18/6 intermittent fasting can help lower the risk of developing these diseases. Studies have found that intermittent fasting can reduce inflammation markers in the body, leading to improved overall health.
May help balance blood sugar levels
By limiting the time frame in which you consume your calories, your body is better able to regulate blood sugar levels. This balance helps reduce the risk of diseases later in life.
Heightens energy levels
Many people who practice intermittent fasting report feeling more energized during the day. Fasting triggers a natural release of adrenaline and other hormones, leading to increased alertness and focus. Additionally, fasting can help regulate sleep-wake cycles, leading to better sleep quality and increased energy levels during the day.
May improve sleep.
Speaking of sleep, 6-hour eating window may also improve your sleep. Most people doing 18:6 end their meals between 6:30 - 7:30 pm, rather than eating right before sleeping. The structure of consciously timing your meals and not eating late helps regulate your sleep cycles, leading to better sleep quality and more restful nights.
Summary
- Intermittent fasting can help you take control of your day and includes benefits like weight loss, reduced inflammation, better sleep, and more energy.
HOW EFFECTIVE IS THE 18:6 FASTING SCHEDULE?
Numerous research studies on both animals and humans have shown a handful of benefits to practicing intermittent fasting (IF). Studies have shown intermittent fasting to be effective at supporting healthy blood pressure and resting heart rate. As for weight loss, IF can effectively help lose around 0.8% to 13.0% of your body weight in multiple studies ranging from 2 weeks up to a full year.
However, a recent study at John's Hopkins showed IF wasn't associated with weight loss, but the age old "fewer and smaller meals" is the more effective weight loss strategy.
Summary
- Some studies show effective weight loss through IF, while others show it isn't more effective than "fewer and smaller meals."
WHAT SHOULD YOU EAT TO BREAK A FAST?
You will likely be starving when it's finally time to start your eating window, but make sure you plan ahead for how you are going to break your fast. You can read the read the complete guide here, but to summarize:
START SMALL
Ease your system back into gear with something under 500 calories and easily digestible.
HYDRATE
Drink water during and after you break your fast. There are countless benefits to being hydrated.
EASILY DIGESTIBLE FOODS
Fruits, vegetables, and lean protein. Avoid eating heavy, high fat, high carb, and sugary foods. Here is a great lean protein that helps you burn fat.
AVOID SUGAR OR PROCESSED FOODS
The rapid spike in blood glucose will definitely end up making you tired.
Summary
- Don't ruin the hard work by binging eating awful foods after your fast. Ease in, start small with easily digestible foods. Avoid heavy, high fat, high carb meals and especially avoid sugary foods.
CONCLUSION
Short term diets are not a long term solution, but the nutrition & lifestyle choices made while 18:6 IF could be beneficial if added to your consistent routine. Once your body adjusts, it should become easier. It takes 66 days to make a habit automatic, but you can do this!
FAQ
How often should you do intermittent fasting?
How often you fast is completely up to your personal preference and depending on your health conditions as well as what goals you are looking to achieve.
Is intermittent fasting safe?
If you have concerns you should consult your doctor before making any dietary changes. A fast should always be planned ahead including timing, hydration, and breaking the fast. Pay very close attention to how your body feels and what it is signaling.
What are the rules for 18:6 fasting?
18:6 intermittent fasting is when the fasting period is 18hrs and consists of absconding from food. You should choose whichever window suits you the most. You might start with 1:30pm and then finish with the dinner at 7:30pm.
You can drink liquids that don't contain calories like water, herbal tea, or black coffee.
Anything over 50 calories would be considered breaking the fast and disrupting the metabolic state otherwise achieved through fasting.
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4 Responses
Robert w
Thank you for your. Write-up. Going to get my self better versed up on this ketosis. Have been doing the 18/6 first for past 3 weeks, Only had 1 major previous diet, low carb diet which was effective, until I fell off wagon, I hope to combine, low carb diet with the fasting along with a set of rules or principle . Last few weeks have had a bit of success on my journey to lose 32 kilos, loosing 7 kilos . Your comment on Ketosis grabbed my attention , I feel like I shredding weight particularly last couple hour of fast? Is that something u can feel? Particularly when I’m walking or exerting last couple hours of fast. Or is that just the hunger pains. Thank for your insights
Cheers rob
Taylor Ford - The Driven
Martha, that is incredible! Has it helped and how do you feel?
Martha Rampton
I can only fast 14-15 hours. Does that do any good?
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Mike W
September 06, 2023
Hi; I am very interested in doing the 16/8 fasting diet program, but my question is, as I read up on what foods are good to eat during my 8hr fasting window, Im wondering how MUCH of each food type can I eat? Like for instance, one suggestion was eating a salad, but how much of a salad? What should the salad include? Should I eat a small salad, a big salad? Is a small salad at like Salata sufficient?