Intermittent Fasting 101

Intermittent fasting, also called IF, is pretty simple. You eat within a shortened period of time, and you fast the rest of the time. If you’re not eating right now, you’re fasting. If you extend your fast a bit longer, you can benefit from it — namely, weight loss, improved focus and steady energy, among other benefits. (Bye, sugar cravings.)

Intermittent fasting is good for you, and it’s really easy to do. Keep reading to learn the facts, plus tips so you can get started today.

smiling guy holding coffee mug

What is intermittent fasting?

When you fast intermittently, you eat within a shortened time window — usually 8-10 hours. For example, you eat your regular dinner and stop eating at 8 p.m. The next day, you skip breakfast and have your first meal at noon.

During your fast, you can drink plain water, coffee and tea. If you’re following Bulletproof Intermittent Fasting (more on that later), you’ll have creamy Bulletproof Coffee in the morning to hold you over until lunch.

So, why do people fast? Although weight management is definitely one of the benefits of intermittent fasting, it’s not really a diet. It’s an eating schedule that has big payoffs over time, like regulating your insulin levels, protecting against disease and — yup, helping you manage your weight.

This might go against what you’ve heard about eating frequency in the past. Skipping a meal won’t send your body into “starvation mode.” And although there’s nothing wrong with eating breakfast, there are major benefits to giving your body an extended break between meals.

Nervous system computer generated image

The science of intermittent fasting

When you eat, a lot happens in your body:

  • Depending on what you’ve eaten, your blood glucose (sugar) levels will rise.
  • Your pancreas produces a hormone called insulin.
  • Insulin tells your cells to fuel up on glucose as your gut breaks down your food.
  • Your body releases hormones like cholecystokinin (CCK) and leptin, which signal when you’re full.

However, when you eat a lot of carbs and sugar, ignore your body’s “I’m full!” signals and eat frequently without burning off all that energy, your body struggles to keep up. Your pancreas has to work overtime, and any extra glucose gets stored as fat. Over time, those factors can increase your risk of weight gain, insulin resistance and diseases like diabetes and cancer. Yikes.

That’s one of the many reasons intermittent fasting is so effective: It gives your body time to reset. When you take a break between meals, your glucose levels remain stable, your insulin levels drop and your body has a chance to clean up shop (more on that below) — all of which leads to major benefits like increased energy and brain function.

Woman's feet standing on bathroom scale

Benefits of intermittent fasting

Weight: Your body preferentially uses glucose (carbs) for energy. When you fast, your body uses up available glucose, and then transitions to burning fat for fuel — which can produce ketones. Plus, intermittent fasting can help prevent insulin resistance and leptin resistance, which may assist with weight management.[1][2][3]

Helps remove cellular waste: Over time, your cells naturally accumulate damaged cells and waste — junk that can interfere with cellular function. Intermittent fasting promotes a process called autophagy, which is what happens when your body clears out the gunk so your body can work even better.[4]

Supports healthy aging: Studies show that intermittent fasting can help protect your cardiovascular system and how you manage blood sugar to support healthy aging. It even helps promote feelings of tranquility and alertness.[5][6][7]

These are just a few notable callouts — turns out, fasting is really good for you on tons of different levels. 

Picture of healthy-looking food

How to do intermittent fasting

Ready to get started? Great! One of the best parts of intermittent fasting is that it’s really easy to adapt to your daily schedule. You can do it every day, or you can do it just a few times a week. You can even customize the amount of time you spend between meals — which is good news if you have a variable schedule. What matters is that it works for YOU.

Styles of intermittent fasting*


You eat normally five days a week. On the other two days, you “fast” by eating between 500 and 600 calories.

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.


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 remain in a fasted state so you reap all the benefits of intermittent fasting.

*As with any diet or exercise plan, consult your healthcare provider to determine what’s best for you.

Bulletproof Coffee in a beaker mug

Why you should try Bulletproof Intermittent Fasting

There’s one big downside about plain intermittent fasting: It can leave you feeling hungry, tired and distracted because, well, you’re skipping meals. It’s hard to crush your to-do list when you’re just thinking about lunch. To get the benefits of intermittent fasting, you need to stick with it and power through the initial feelings of fatigue.

Bulletproof Intermittent Fasting solves a lot of the problems associated with plain intermittent fasting — that’s why we recommend it, especially if you’ve never fasted before. When you start your morning with a satisfying cup of Bulletproof Coffee, the quality fats push you into a mild state of ketosis — which curbs cravings and fuels your body all morning long.

Won’t Bulletproof Coffee break the fast? Nope. Bulletproof Coffee is full of quality fats from Brain Octane oil and grass-fed butter, which keep you full and focused without switching on digestion. By keeping carbs and proteins out of the picture, you remain in a fasted state — but you’ll feel energized, not like a hungry zombie.

Sample Bulletproof Intermittent Fasting schedule

  • Finish dinner by 8 p.m.
  • Drink a cup of Bulletproof Coffee in the morning.
  • Eat a high-fat, moderate protein, low-carb lunch at 2 p.m.
  • Finish eating the next day by 8 p.m.

Repeat this schedule every day, or just a few times per week

The biggest takeaway here is that there is no one-size-fits-all approach to intermittent fasting. Take time to find the perfect fit, pay attention to how you feel and don’t be afraid to experiment with different schedules. Check with your doctor before you try intermittent fasting, especially if you’re taking any medications.

The bottom line: Intermittent fasting has tons of benefits. Bulletproof Intermittent Fasting makes it easier.

Essential intermittent fasting products

Brain Octane oil

Woman pouring Brain Octane oil into a blender

When it comes to MCT oils, Brain Octane oil is the best of the best. It’s C8 (caprylic acid) MCT oil, which produces four times more ketones than plain old coconut oil. That means it’ll help curb cravings and burn fat — which is why it’s an essential part of Bulletproof Coffee when you’re following Bulletproof Intermittent Fasting.

Even if you aren’t starting your morning with the Bulletproof Coffee recipe, blend Brain Octane oil into your coffee or tea — it’ll help hold you over until you break your fast, and the extra ketone energy will keep you fueled and focused.

Grass-Fed Ghee

Jar of Bulletproof ghee

It’s butter, but better. If you’re sensitive to dairy, use Grass-Fed Ghee instead of butter in your Bulletproof Coffee. Ghee is prepared in a way that removes nearly all lactose, so it’s kinder to dairy-intolerant people. Get it in a starter kit with all the ingredients for Bulletproof Coffee.

Bulletproof Coffee Cold Brew - Original

Woman opening a Bulletproof cold brew coffee

Because it doesn’t have any protein or carbs, Bulletproof Coffee Cold Brew - Original is perfect for on-the-go fuel without breaking your fast. It’s made with the same quality fats as Bulletproof Coffee — Brain Octane oil and grass-fed butter — but it’s conveniently pre-made and ready to go.

Bulletproof Coffee Beans

Bulletproof coffee bean bag and grounds

Even if you’re on a plain fast, you can have water, plain tea and black coffee — and if you’re a daily coffee drinker, you deserve the best cup possible. Bulletproof Coffee beans are premium, single-origin beans that are tested for toxins before they meet your mug. Learn more about what makes Bulletproof Coffee Beans different.