Research shows intermittent fasting to be a powerful tool for helping you reach and maintain a healthy weight.

Learn how intermittent fasting works with your body to rewire your metabolism — and deliver additional health benefits, too.

Find the type of intermittent fasting that’s right for you, and learn what to eat between periods of fasting in order to maximize your results.

Want to fast without feeling hangry? Bulletproof Intermittent Fasting delivers the benefits of fasting and curbs the hunger cravings that can take you off track.



Fasting means you aren’t eating for an extended period of time. If you think about it, fasting isn’t all that unnatural. Your ancestors evolved to thrive in situations when food was scarce.[1] Intermittent fasting — cycling in and out periods of fasting and eating — is a simple eating plan that makes the most of your body’s own fat-burning systems. Research shows that intermittent fasting is a proven way to help people manage their weight.[2]

In a Bulletproof Radio podcast episode, Dr. Sylvia Tara, PhD, author of “The Secret Life of Fat,” said starting the routine is hardest part of intermittent fasting — but after six to eight weeks, she didn’t feel the same food cravings. Her advice for weight management with intermittent fasting? “For people who have those 20 pounds, know, number one, it can be done. Number two, it might be a bit more effort than you thought it was going to be … Third, know that it gets easier with time and you can maintain it. It really isn’t as bad once you get into it, and it’s extraordinarily effective.”

There are lots of different approaches to weight loss — but we’re here to talk about weight management, which means adopting lifestyle modifications to stay at a healthy weight. Think of intermittent fasting as a tool to add to your wellness toolkit. Read on for the science behind intermittent fasting and weight management, plus tips to maximize your fast.

How weight management works with intermittent fasting

When you’re intermittent fasting, you eat all the food your body needs, but during a shorter period of time. There are many methods, but the most common involves eating during a six- to eight-hour window and fasting the remaining 14 to 16 hours. It’s not as bad as it sounds, especially when you add Bulletproof Coffee to keep hunger levels in check (more on that later).

Intermittent fasting triggers a perfect storm of metabolic changes to tackle weight management and fat reduction. How does it work?

Reduces calories : If you’re a snacker or tend to grab food on the go, you may be eating more calories than your body needs — and that will show up on the scale. In general, you tend to eat less when you limit the amount of time you can eat during the day.

: If you’re a snacker or tend to grab food on the go, you may be eating more calories than your body needs — and that will show up on the scale. In general, you tend to eat less when you limit the amount of time you can eat during the day. Kickstarts ketosis : Intermittent fasting is a pathway to the fat-burning state of ketosis. During your fast, your body burns through its glucose reserves (aka carbohydrates) for energy. Then, you start burning fat for fuel. To support weight management, eat a ketogenic diet between periods of fasting. [3] Learn more about the keto diet here.

: Intermittent fasting is a pathway to the fat-burning state of ketosis. During your fast, your body burns through its glucose reserves (aka carbohydrates) for energy. Then, you start burning fat for fuel. To support weight management, eat a ketogenic diet between periods of fasting. Learn more about the keto diet here. Lowers insulin levels : Intermittent fasting affects insulin in two ways. First, your body becomes more sensitive to insulin, which can help prevent weight gain and reduce your risk of diabetes. Second, fasting decreases your insulin levels, which can cue your body to start burning stored fat instead of glucose. [4]

: Intermittent fasting affects insulin in two ways. First, your body becomes more sensitive to insulin, which can help prevent weight gain and reduce your risk of diabetes. Second, fasting decreases your insulin levels, which can cue your body to start burning stored fat instead of glucose. Boosts metabolism: In rodent studies, intermittent fasting reprogrammed metabolic pathways to get more energy out of food.[5] Fasting also increases your levels of adrenaline and noradrenaline, hormones that help your body free up more stored energy (that’s your body fat) during a fast.[6][7] Boosting your resting metabolism helps your body burn more calories throughout the day, even while you rest. Get the details on ways to boost your metabolism.

Multiple studies show that intermittent fasting supports weight management. In a 2015 review pooling 40 different studies, participants lost 10 pounds in a 10-week period on average.[8] Another smaller study of 16 obese adults following an “alternate day” intermittent fasting schedule (eating 25 percent of their daily calories on one day, and eating normally the following day) resulted in them losing up to 13 pounds over 8 weeks.[9]

Intermittent fasting also succeeds where many weight-loss regimes fail: by targeting and reducing visceral fat. Visceral fat is the stubborn, internal fat packed deep around your abdominal organs. During a period of six months, people on an intermittent fasting diet were able to shed four to seven percent of their visceral fat.[10][11]

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Additional benefits of intermittent fasting

Intermittent fasting isn’t just about achieving a healthy weight. Here are some additional benefits you’ll experience along the way:

How to start intermittent fasting

There is more than one way to start intermittent fasting, which is great because every BODY is different. The key is to experiment and listen to your body to see what works best for you. Here are some of the ways to get started:

16:8 : You eat all of your daily calories within a shortened period (typically 6-8 hours) and fast the rest of the time.

: You eat all of your daily calories within a shortened period (typically 6-8 hours) and fast the rest of the time. Bulletproof Intermittent Fasting : Similar to 16:8, but with one crucial difference so you don’t get hangry: You drink a cup of Bulletproof Coffee in the morning. The quality fats keep you full until lunch, and you continue autophagy and fat-burning so you reap all the benefits of intermittent fasting. And don’t worry — Bulletproof Coffee won’t break your fast.

: Similar to 16:8, but with one crucial difference so you don’t get hangry: You drink a cup of Bulletproof Coffee in the morning. The quality fats keep you full until lunch, and you continue autophagy and fat-burning so you reap all the benefits of intermittent fasting. And don’t worry — Bulletproof Coffee won’t break your fast. One meal a day (OMAD) : Also known as eating once a day. You eat all of your daily calories in just one meal each day, and fast the rest of the day.

: Also known as eating once a day. You eat all of your daily calories in just one meal each day, and fast the rest of the day. 5:2 : You eat normally five days a week. On the other two days, you “fast” by eating between 500 and 600 calories.

: You eat normally five days a week. On the other two days, you “fast” by eating between 500 and 600 calories. Alternate Day Fasting: You alternate a day of eating normally with a day eating 25 percent of your typical daily calories. A study found that obese adults following an “alternate day” intermittent fasting schedule lost up to 13 pounds over 8 weeks.[25]

Related: Want to Try a Fasting Diet? How to Choose the Right One

If intermittent fasting causes fatigue or other negative symptoms, try fasting just once or twice a week, and build up from there. As with any diet or exercise plan, consult your healthcare provider to determine what’s best for you.

Tips for intermittent fasting for weight management

It’s not easy to resist the cravings, but there are some easy ways to avoid feeling hungry that can also help you get even more out of your fast:

Don’t skip breakfast

We know — going without your morning meal can be hard. So, instead of skipping breakfast, enjoy a creamy cup of satisfying Bulletproof Coffee. This simple step won’t stop the benefits of a fast, and it keeps the “hangries” away while nourishing your body with good fats.

Eat the right fats

The ultimate hack for your intermittent fast: Bulletproof Brain Octane MCT oil and MCT oil. They’re MCT oils, but better. Your body turns MCTs into ketones, which help burn fat, curb cravings and power your brain with more energy, better mental performance and fewer cravings.[26] [27] [28]

Cut back on carbs

Follow the Bulletproof Diet during your eating periods to supercharge the impact of intermittent fasting. Restricting carbohydrates will decrease your appetite (bye cravings!) and make it easier for your body to shift into fat-burning ketosis.

Plan meals ahead of time

When it’s time to eat, those sweets and snacks start looking mighty tempting. To avoid bingeing on carbs or junk food, prepare healthy options ahead of time with the right fats, high-quality meats and vegetables. These keto meal prep recipes will help you stay on track.