16:8 Intermittent Fasting: A Beginner’s Guide

Want to try intermittent fasting but not sure where to start? Many people are trying 16:8 intermittent fasting. It’s one of the most popular ways to fast.

The 16:8 intermittent fasting appeals to many because it’s simpler than other diets. You don’t need to count calories or avoid certain foods. Instead, you just focus on when you eat. This makes it easier to stick with long-term.

This guide will show you everything you need to know about 16:8 intermittent fasting. You’ll learn what it is, its benefits, and potential side effects. You’ll also find out who should avoid it and how to start fasting. Let’s get started!

Table of Contents

• What is 16:8 intermittent fasting?
• The benefits of 16:8 intermittent fasting
• The potential side effects of 16:8 intermittent fasting
• Who should avoid 16:8 intermittent fasting
• How to start 16:8 intermittent fasting
• 16:8 Intermittent fasting FAQs
• Closing remarks

What is 16:8 intermittent fasting?

16:8 intermittent fasting is a fasting routine where you fast for 16 hours and eat during an 8-hour window each day. For example, if you finish dinner at 8 PM, you wouldn’t eat again until 12 PM the next day. During the fasting period, you can drink water, black coffee, or plain tea.

This method is one of the most popular types of intermittent fasting because it’s easier to follow than other approaches. Think of it as an extension of what your body already does when you sleep. You naturally fast while sleeping, and 16:8 fasting simply extends this period a bit longer.

The science behind choosing 16 hours for fasting is interesting. After 12 hours without food, your body starts making important changes. When your food supply runs out, your body switches to burning stored fat for energy. During this time, it also kicks off important cell repair processes.

As you continue fasting, your blood sugar levels naturally balance out. This avoids the usual spikes and crashes that come with regular eating. Fasting may also help boost brain function. Many people report feeling mentally sharper during their fasting period.

The 8-hour eating window is long enough to fit in 2-3 healthy meals without feeling rushed or deprived. This balance makes 16:8 fasting practical for most people’s schedules and lifestyles.

Remember, you don’t have to jump right into 16 hours of fasting. You can start with 12 hours and gradually work your way up to 16 hours as your body adjusts.

The benefits of 16:8 intermittent fasting

In the previous section, I briefly mentioned the benefits of 16:8 intermittent fasting. Now, we will explore these benefits more fully. Please note that these benefits can vary greatly from person to person.

1. Weight loss

When you eat during a shorter time window, you naturally eat fewer calories. Plus, many people find this eating pattern easier to stick to than traditional diets. This is because you focus on when to eat, not what to eat.

A 2023 study found that 16:8 intermittent fasting combined with calorie restriction significantly reduced body weight compared to calorie restriction alone. Also, a 2016 study of resistance-trained males showed that 16:8 intermittent fasting decreased fat mass while maintaining muscle mass.

2. Better blood sugar control

Fasting gives your body a break from processing sugar. This helps your body become better at managing blood sugar levels. Over time, your cells become more sensitive to insulin. The 2016 study mentioned above found that 16:8 intermittent fasting decreased blood glucose and insulin levels while improving insulin sensitivity.

3. Less inflammation

Fasting helps calm down inflammation throughout your body. Less inflammation means better overall health, less pain, and lower risk of many diseases. It’s like turning down the heat on your body’s stress response. The 2016 study mentioned above showed that 16:8 intermittent fasting decreased inflammation markers in the participants.

4. Better metabolism

Regular fasting periods can help tune up your metabolism. Your body becomes better at switching between using food and stored fat for energy. This means more stable energy throughout the day and better nutrient processing. It also helps with weight loss.

5. Improved cellular repair

During fasting, your body starts cleaning up and repairing damaged cells. Think of it like your body doing spring cleaning. This process, called autophagy, helps keep your cells healthy. It may also slow down aging.

6. Better digestion

Giving your digestive system regular breaks through fasting can improve gut health. Your gut gets time to rest and repair itself. But, some people might also experience digestive issues during intermittent fasting.

7. Better cognitive function

Many people report thinking more clearly during their fasting period. Your brain functions better when it’s not constantly processing food. You might notice better focus, clearer thinking, and less mental fog.

8. Better emotional regulation

Once you adjust to fasting, you might find your moods become more stable. You’re less likely to have energy crashes that affect your mood. Many people feel more in control of their emotions during intermittent fasting.

9. Better sleep quality

As your body adjusts to fasting, you might sleep better at night. This could be because fasting helps regulate your body’s natural daily rhythms. Better sleep means more energy during the day.

10. Better relationship with food

Fasting helps you recognize true hunger versus emotional eating. You’ll learn to eat when your body needs food, not just when you’re bored or stressed. This can lead to healthier eating habits.

The potential side effects of 16:8 intermittent fasting

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Besides its benefits, 16:8 intermittent fasting also has potential side effects. These side effects can vary greatly from person to person. Most side effects are temporary and improve as your body adjusts. But if you experience severe or persistent side effects, stop fasting and see your healthcare provider.

1. Hunger and cravings

During your first few weeks of fasting, you’ll likely feel hungry during fasting hours. You might also have strong cravings for food. These feelings usually get better as your body adjusts to the new eating pattern.

2. Dehydration

Not drinking enough water during fasting can lead to dehydration. This can cause headaches, dizziness, and fatigue. Remember to drink plenty of water throughout the day.

3. Headaches and lightheadedness

Some people get headaches and feel dizzy when they start fasting. This often happens because of dehydration or low blood sugar. Drinking enough water and eating well during your eating window can help prevent this.

4. Low energy and fatigue

During the first few weeks, you might feel tired and have less energy than usual. This happens as your body learns to use stored fat for energy instead of regular meals. It could also occur if you are dehydrated.

5. Digestive issues

Your digestive system needs time to adjust to the new eating schedule. So, you might experience nausea, diarrhea, or bloating at first. These problems usually improve with time. If you’re interested, read my other article about intermittent fasting and diarrhea.

6. Mood changes

You might feel irritable or anxious when you first start fasting. This is normal as your body adjusts to not eating during certain hours. These mood changes typically improve after a few weeks.

7. Sleep problems

Some people have trouble sleeping when they first start fasting. This might happen because of hunger or changes in your eating schedule. Your sleep usually improves as your body adjusts.

8. Bad breath

During fasting, your body produces more ketones, which can cause bad breath. Drinking water and maintaining good oral hygiene can help manage this.

9. Hair loss

There isn’t much research directly linking intermittent fasting to hair loss. But some people notice more hair falling out during intermittent fasting. Hypothetically, intermittent fasting could contribute to hair loss. Read my other article to learn more about intermittent fasting and hair loss.

10. Malnutrition (if not done properly)

If you don’t eat enough nutritious food during your eating window, you might become malnourished. This can cause various health problems. Make sure to eat a balanced diet when you do eat.

Who should avoid 16:8 intermittent fasting

While 16:8 intermittent fasting has health benefits, it’s not safe for everyone. Some people should avoid it, while others should try it under a doctor’s supervision. Here’s a list of people who should avoid or be careful with 16:8 intermittent fasting.

1. Pregnant women

Pregnant women need steady nutrition to stay healthy and support their baby. Fasting might deprive the baby of nutrients. It may also affect hormone balance. Women trying to conceive should also avoid fasting, as it can disrupt hormones and lower fertility.

2. Breastfeeding mothers

Breastfeeding women need extra calories and nutrients to produce milk and stay healthy. Fasting could reduce milk supply and lower its quality. It might also lead to fatigue and dehydration, making it harder to care for the baby.

3. People with blood sugar issues

People with type 1 diabetes should avoid fasting because they need regular insulin. Those with low blood sugar or severe insulin resistance should also avoid fasting, as it can worsen their condition. People with type 2 diabetes may try fasting, but only under a doctor’s guidance. If you have blood sugar issues and are considering fasting, talk to your doctor first.

4. People with a history of eating disorders

Fasting could trigger or worsen disordered eating. It might lead to unhealthy relationships with food, binge eating, or other harmful behaviors. Anyone with a history of eating disorders should avoid fasting.

5. Underweight people

Underweight people shouldn’t limit their eating times. This could lead to more weight loss, nutritional deficiencies, and health problems. The focus should be on gaining a healthy weight through regular, nutritious meals.

6. Teenagers and children

Young bodies need regular nutrients to grow and develop properly. Fasting could interfere with their physical and mental growth. It may also affect school performance and disrupt healthy eating habits. Children and teens should keep regular eating patterns.

7. Older adults

Older adults often struggle to maintain proper nutrition and muscle mass. Fasting might increase their risk of falls, weakness, and malnutrition. They also often take medications that need to be taken with food.

8. People taking medications that need food

Many medications must be taken with food to work properly or avoid side effects. Fasting could affect how these medications work. It may also cause stomach issues. Talk to your doctor about your medication schedule.

9. People with low blood pressure

Fasting can lower blood pressure more, leading to dizziness, fainting, and other issues. If you already have low blood pressure, fasting might make your symptoms worse. It could also increase your risk of falls.

10. People with certain chronic conditions

Certain conditions like gastric ulcers, severe kidney disease, heart problems, and adrenal insufficiency require regular food intake. Fasting could make these conditions worse. It may also interfere with treatment. Talk to your doctor about your specific condition.

How to start 16:8 intermittent fasting

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Starting 16:8 intermittent fasting doesn’t have to be complicated. The key is to begin slowly and adjust gradually.

First, pick your 8-hour eating window. Choose times that work best with your schedule. For example, if you usually eat dinner at 7 PM, you might set your eating window from 11 AM to 7 PM. This means you’ll fast from 7 PM until 11 AM the next day.

Don’t jump straight into a 16-hour fast if you’re not used to it. Start with a 12-hour fast and gradually increase it. For example, if you finish dinner at 7 PM, try not eating until 7 AM the next day.

Then, extend your fasting period by 1-2 hours every few days as your body adjusts. Some people reach 16 hours within a week, while others prefer taking 2-3 weeks. Listen to your body and adjust at your own pace.

During your fasting hours, you can drink water, black coffee, or plain tea. These drinks help manage hunger and keep you hydrated. Avoid drinks with calories, sugar, or artificial sweeteners as these can break your fast.

When it’s time to eat, start with a light meal. Don’t overeat just because you’ve been fasting. Focus on nutritious foods like proteins, vegetables, fruits, and whole grains. Try to eat balanced meals during your eating window.

Listen to your body as you adjust. It’s normal to feel hungry at first, but this usually improves within a few weeks. If you feel unwell, consider extending your adjustment period or consulting your doctor.

Remember, consistency matters more than perfection. It’s okay to be flexible with your fasting schedule when needed. The goal is to find a sustainable routine that works for you in the long run.

16:8 Intermittent fasting FAQs

Here are common questions about 16:8 intermittent fasting, especially from beginners. The answers will show you what to expect. They will also help you handle common situations.

What can I drink during fasting?

You can drink very low- or no-calorie beverages that don’t trigger a significant insulin response. Water, plain black coffee, and unsweetened tea are common options. Avoid drinks with sugar, milk, cream, or artificial sweeteners. Also, avoid fruit juices, soda, and alcohol.

Can I exercise while fasting?

Yes, you can exercise while fasting, but start slowly and listen to your body. Light to moderate exercise is usually fine. If you’re new to fasting, exercise during your eating window at first. Stop exercising if you feel dizzy or extremely weak.

How long until I see results?

Most people notice changes within 2-8 weeks of consistent fasting. Results vary depending on your starting point, diet quality, and lifestyle. Some notice better focus within days, while weight loss might take longer.

Can I take supplements while fasting?

Supplements without calories or sugar won’t break your fast. Avoid those with calories or sugar during fasting. Also, avoid those that should be taken with food to work properly or prevent stomach upset. Check your supplement labels for calorie content, ingredients, and instructions. If in doubt, take them during your eating window.

Can I change my fasting window occasionally?

Yes, you can adjust your fasting window to fit your schedule. The important thing is maintaining the 16-hour fasting period, not the exact timing. This flexibility helps you stick with fasting long-term.

What should I do if I accidentally eat during fasting?

Don’t worry, just get back on track with your next planned fast. One slip-up won’t ruin your progress. Remember, consistency over time matters more than perfection. Avoid the “all or nothing” mindset.

Should I count calories during my eating window?

While counting calories isn’t required, being mindful of what you eat helps. Focus on nutritious, filling foods rather than strict calorie counting. Fasting isn’t a license to overeat during your eating window.

How do I handle social events during fasting hours?

Adjust your fasting window for special events. Or, schedule social events during your eating window when possible. If you can’t avoid a special event during your fasting window, take only a small portion. Remember, occasional flexibility won’t harm your long-term progress. The key is getting back to your regular schedule afterward.

Closing remarks

Some research has shown the benefits of 16:8 intermittent fasting. But, the long-term effects are still being studied. Like any eating pattern, it works better for some people than others. The key is to start slowly and listen to your body.

Remember that 16:8 intermittent fasting is just one approach to healthy living. What matters most is finding a sustainable way of eating that fits your lifestyle. If you try it and it doesn’t feel right, that’s okay. There are many other ways to improve your health.

If you decide to try 16:8 intermittent fasting, be patient with yourself. Focus on making small, gradual changes. Pay attention to how you feel, not just what the scale says. And most importantly, talk to your doctor before starting, especially if you have any health concerns.