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Home Fasting 18:6 Fasting: An Extended Guide

18:6 Fasting: An Extended Guide

Last update: Jun 25
Last update: Jun 25
reading-time8 min
18-6 fasting

Are you looking for the right intermittent fasting diet?

Perhaps you want an upgrade from the 16:8 method, or maybe you’re looking for something a bit more challenging. If so, the 18:6 method is an excellent choice. It extends the fasting window to boost your fat-burning progress and increase the benefits of intermittent fasting.

Some intermittent fasting schedules are highly restrictive and difficult to maintain for the long periods required. The 18:6 method falls somewhere in the middle. You can fit plenty of nutrients into your 6-hour eating window while fasting long enough to see real progress.

Read on for our complete guide to 18:6 intermittent fasting.

18:6 Intermittent Fasting: What Is It?

18:6 intermittent fasting is a popular fasting plan that involves no food intake for 18 hours and a 6-hour window where you can eat. Most people fit in two meals and a snack during the eating window. For example, you could skip breakfast and have your first meal at midday, a snack in the mid-afternoon, and your last meal at dinner, before starting your fast.

You can tailor the 18:6 schedule to match your lifestyle, but you need to determine your 6-hour window. With fewer hours to eat, it can be difficult to squeeze in all your daily calories. For this reason, you tend to consume fewer calories overall, promoting a calorie deficit.

18-Hour Fast Benefits

18:6 intermittent fasting brings multiple health benefits. It’s not only great for losing weight, but it can also aid other aspects of your overall health. If you’re still on the fence about whether to try 18:6 intermittent fasting, keep reading to discover why it might be worthy of your time.

Here are 5 health benefits:

#1 Increases HGH levels

The human growth hormone (HGH) is a natural hormone made in the pituitary gland. It ensures growth in children and continues to aid health in adulthood. It has several responsibilities, including maintaining normal metabolism and regulating blood sugar levels.

Intermittent fasting enhances the secretion of the human growth hormone. The human growth hormone helps regulate body composition as it works to reduce and redistribute body fat. Higher HGH levels may, therefore, contribute to overall fat and weight loss success.

#2 Balances blood sugar

Intermittent fasting has therapeutic effects on people with impaired blood glucose and lipid metabolism. The eating pattern can improve glycemic control and reduce insulin resistance, making it a potential non-medicinal treatment plan for managing type 2 diabetes mellitus.

Under controlled conditions, intermittent fasting may be a positive weight loss strategy for people with diabetes. In addition, losing weight can naturally reduce your blood sugar levels. Long-term high blood glucose can contribute to cardiovascular diseases, like heart disease and stroke.

#3 Reduces risk of chronic diseases

18:6 intermittent fasting can reduce risk markers of chronic diseases.

It can reduce insulin resistance and lower blood pressure and cholesterol levels, all factors that put you at high risk for developing cardiovascular diseases. Furthermore, intermittent fasting and calorie restriction can reduce inflammation – a common driver of many chronic diseases.

In reducing blood pressure, glucose, and cholesterol levels, fasting supports your overall heart health.

#4 Autophagy

Autophagy is essentially a clean-up job of your body’s old and damaged cells. It is a natural metabolic process that occurs when you deprive your body of nutrients. Autophagy promotes cellular repair, helping your cells to function more efficiently and removing cellular waste.

Intermittent fasting can induce autophagy, but triggering the phase usually requires extended fasting to allow glucose and insulin levels to drop significantly. An 18-hour fast is an ideal place to start, as this will give your body time to deplete your glucose stores and lower insulin.

#5 Weight loss

Weight loss is a known IF benefit and the most popular reason people try 18:6 intermittent fasting. Reducing your eating windows and cutting out food for extended periods causes a metabolic switch that sees your body tap into fat stores for energy to fuel your system.

Weight loss

It helps you burn fat naturally while decreasing your overall calorie intake. Once your body adapts, many people find that intermittent fasting suppresses appetite and reduces food cravings. When you do it right, you can fast as part of a healthy lifestyle for weight control.

Who Should Not Try 18:6 Fasting?

Intermittent fasting is not for everyone. It is only recommended for healthy adults and not for those with underlying health conditions unless under the supervision of a doctor. Practicing intermittent fasting without checking with your doctor first can harm your health.

18:6 intermittent fasting, along with other methods and modifications, is not advised for the following people:

  • Children and adolescents
  • Pregnant and breastfeeding women
  • People who are underweight, with a BMI under 18
  • People with or with a history of eating disorders, as intermittent fasting may encourage disordered eating
  • People with diabetes who are on medication
  • People taking medication for other health conditions

How Many Calories to Eat During 18:6 Intermittent Fasting?

How many calories you need during your eating window depends on your personal needs. Factors like age, sex, current weight, and body composition play a role. To lose weight, you need to create a calorie deficit. That means burning more calories than you consume.

Most people can lose weight safely and successfully with a daily deficit of 500–750 calories. As you likely won’t fit your usual three meals into the shorter eating window, reducing your overall caloric intake naturally with 18:6 intermittent fasting is possible.

So, if you usually consume 2,000 calories per day, you could aim for 1,250–1,500.

How to Follow the 18:6 Intermittent Fasting Regimen?

So, you know the benefits of intermittent fasting, but how do you start with 18:6?

You should never jump headfirst into an intermittent fast without a little preparation. Otherwise, you might struggle to sustain the fast and wind up quitting early. You can do many things to get organized and ensure you make your fast as comfortable as possible.

Below, you can find 4 strategies for success with this regimen.

#1 Start slow

With intermittent fasting, it’s better to start with a longer eating window and gradually reduce it as you become more comfortable with food abstinence. Jumping straight into an 18-hour fast will leave you battling tiredness, cravings, and hunger pangs while fasting.

If you’re a beginner, you should start with an easier form of intermittent fasting to prepare yourself for longer fasts. Lots of people move onto the 18:6 after trying the 16:8 fast, which is easier to handle. The 16:8 requires a 16-hour fasting window and an 8-hour eating window.

#2 Plan your fast

When you plan ahead, you can prepare for possible obstacles that might arise during the fasting period. For example, you can ensure you eat the right foods before fasting and have proper hydration. Doing so will help mitigate side effects, like headaches, hunger, and fatigue.

Plan your fast

Planning your fasting window will also ensure that your social plans don’t clash with your diet. For instance, if you are meeting friends for an early dinner, you could begin your six-hour eating window a little later to ensure dinner time is your last meal of the day.

#3 Eat healthy foods on your eating window

Success with intermittent fasting isn’t just about sustaining your fast for the specified period. It’s about adopting a healthier lifestyle and looking after your body overall. So, taking care of yourself outside the fasting window will promote more sustainable weight loss results and other health benefits.

In your eating window, you should focus on eating a healthy diet that includes lots of fruits, vegetables, whole grains, complex carbs, lean protein, fiber, and healthy fats. Try to quit bad habits of an unhealthy diet – cut out or limit junk food and highly-processed foods.

Healthy fats are great for promoting satiety and are a staple of the keto diet, which some people combine with fasting to speed up weight loss.

A Word From Our Nutritionist

18:6 fasting is one of the most favored intermittent fasting regimes.

It is a more advanced fast requiring 18 hours of food abstinence. It brings many health benefits, from blood sugar regulation to stronger heart health. It’s also an effective weight loss strategy as it speeds up fat burning and helps promote greater appetite control.

As 18:6 is not the easiest fast, it can help to prepare yourself. Planning your meals, eating hours, and social calendar are great ways to improve your success rate. When you are organized, you can prepare and eliminate problems that might occur throughout your journey.

During fasting hours, you must ensure that you drink plenty of water and other calorie-free or low-calorie beverages, like black coffee and green tea. It will keep you hydrated and prevent some of the symptoms that arise during fasting, like headaches, irritability, and low energy.

While fewer calories might speed up weight loss, it is critical that you eat enough during your feeding hours. Your body needs lots of nutritious foods full of vitamins and minerals. You could develop nutrient deficiencies and other adverse effects if you don’t eat a balanced diet.

Intermittent fasting isn’t a safe choice for everyone. This is especially true of the 18:6 fasting schedule, as it is a more restrictive form of eating. Always talk to your doctor before attempting a restrictive diet, whether it’s the 18:6, alternate-day fasting, or something else.


Whatever your health goals, the 18:6 fast is a great choice for getting incredible results.

It gives you a smaller eating window, but it’s still possible to eat larger meals and get plenty of nutrition. You should maintain a balanced diet and ensure you get enough calories to keep your system functioning at optimal levels while your body begins burning your stored fat.

Remember, 18:6 is a more advanced form of intermittent fasting. 18 hours is a long time to go without food, and it is not suitable for beginners.

Written by
Anahit Harutyunyan, MD

Anahit Harutyunyan is an MD in Anaesthesiology and Intensive Care. She also has a second specialty as a Medical specialist in Physiatry. Anahit has work experience in different clinics as ICU Doctor and Medical Doctor in Yerevan and Gyumri Ambulance Stations. She also worked in the therapeutic department during covid and has morning consultations in Nor Med private clinic.

18-6 fasting

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