Why Keto Is More Effective With Intermittent Fasting

Why Keto Is More Effective With Intermittent Fasting


  • The keto diet and intermittent fasting work especially well together, especially for weight loss and stable energy.
  • Intermittent fasting is one of the oldest and most widely used performance upgrades in human history. It’s amazing for everything from losing weight to building a stronger brain.
  • Fasting can be challenging on a high-carb diet. Pairing the two can cause unstable blood sugar, cravings, mood swings, and low energy. Keto and IF work better together for boosting fat- and weight-loss results.

It’s impossible to scroll through your social feed without hearing someone tout the benefits of a keto diet. But if you really want to kick it up a notch and boost those fat-burning results, you might want to consider adding intermittent fasting to your low-carb regimen.

Tons of celebs are jumping on the intermittent fasting keto bandwagon, and for good reason. The two work hand in hand to accelerate weight loss, not to mention stimulate lots of other performance-boosting benefits. Fasting is an extraordinary tool for improving your biology. It’s free. It’s universally accessible. It’s adaptable. It’s the reason it’s always been a major part of the Bulletproof Diet.

Read on to find out why keto and intermittent fasting (IF) are the hottest power couple in Hollywood right now, why Bulletproof promotes them both, and how you can make the combined eating style work for you.

Related: What Is Intermittent Fasting? A Complete Beginners’ Guide

Why intermittent fasting is all the rage

It’s astounding how much benefit you can get just from skipping a couple of meals. Intermittent fasting does all kinds of good for your body. Here are seven of its benefits:

Boosts fat loss

keto intermittent fasting weight lossEating all your meals in an 8-hour window (say, eating between noon and 8PM, and fasting the other 16 hours a day) causes significant weight loss without counting calories.[1]  While this type of intermittent fasting causes weight loss no matter what people eat, research shows that people who do it in a healthy manner lose twice as much weight (7% vs. 3% of their body weight) as those who fast while still eating junk. So it’s still important to follow a high-performance diet like the Bulletproof Diet while you fast.

Increases muscle gain

keto intermittent fasting muscleWorried about losing muscle if you fast? Maybe this will put your concerns to rest: a single 24-hour fast increased human growth hormone (HGH) by 2000% in men and 1300% in women.[2]  HGH plays an integral role in building muscle. Boosting your levels this high will have huge effect on your physique. Research shows that higher levels of HGH leads to lower levels of body fat, higher lean body mass and improved bone mass.[3]

Speeds up recovery

keto intermittent fasting benefitsHGH also drives muscle protein synthesis, which speeds up repair and helps you recover faster from a hard workout or an injury.[4]

Makes skin supple

keto intermittent fasting benefitsHGH lowers naturally as you age. But when subjects were given HGH supplements, not only did lose fat and build muscle, their skin thickness improved — making it stronger and more resilient to sagging and wrinkles.[5]

Slows down aging

keto intermittent fasting benefitsFasting ramps up your stem cell production.[6] Stem cells are like biological playdough — your body turns them into any kind of cell it needs and uses them to replace old or damaged cells, keeping you younger on a cellular level. Stem cells are great for your skin, joints, old injuries, chronic pain, and more. You can try stem cell therapy…or you can just fast.

Improves brain function

keto intermittent fasting benefitsFasting helps you build a better brain, too. Intermittent fasting increases a protein in your brain called BDNF that researchers have nicknamed “Miracle-Gro for your brain.”[7] BDNF improves learning and memory and can help you forge stronger neural pathways, making your brain run faster and more efficiently, which is especially important as you age.

Stimulates autophagy

keto intermittent fasting autophagyAutophagy is spring cleaning for your cells. It’s Latin for “self-eating,” which is spot-on: when autophagy turns on, your cells sift through their internal parts, get rid of anything that’s damaged or old, and install shiny new versions.[8] Autophagy is like a tune-up for your car: afterward everything runs more smoothly. It reduces inflammation and even boosts longevity. Intermittent fasting triggers, to quote researchers, “profound” autophagy, especially in your brain.[9]

Lowers inflammation

keto intermittent fasting benefitsIntermittent fasting decreases oxidative stress and body-wide inflammation markers.[10] Inflammation is one of the biggest drivers of poor performance, aging and disease.[11] Keeping inflammation low will increase your longevity and help your body run better.[12]

Related: Forget Juice Cleanses. Autophagy Is the Real Way to Detox Your Body

Intermittent fasting is like a broad-spectrum upgrade for your body. The fact that your biology responds to fasting by getting stronger makes sense from an evolutionary standpoint: it’s precisely when you’re short on food that you need to be running at your best, to increase your chances of finding something to eat in order to survive.

The one problem with intermittent fasting

keto intermittent fasting hungerThere’s one major drawback to intermittent fasting: You can get unstable blood sugar, if you’re eating a lot of carbs.

If you try intermittent fasting with a higher-carb diet, your blood sugar will rise and fall meaningfully throughout the day. It’ll be higher after you feast, then will gradually decline as you get deeper into your fast. Unstable blood sugar brings additional challenges to fasting:

  • You’ll run out of energy. When you don’t have anything in your system for several hours, your blood sugar will eventually drop below baseline. If you’ve ever had a blood sugar crash, you know how this state feels. Sleepiness, trouble focusing, lightheadedness, intense cravings, and the occasional mood swing typically accompany low blood sugar. Your cells run low on fuel and they start demanding that you give them more carbs.[13]
  • You’ll spike your blood sugar when you eat. If you’re fasting on a high-carb diet and you’ve powered through the cravings and lack of energy from low blood sugar, there’s a good chance you’ll eat a ton of carbs when you feast. You want to eat big meals when you fast to make sure you’re getting enough calories, but all those excess carbs in one go will spike your blood sugar in the opposite direction, from low to high.[14] High blood sugar causes fatigue and lack of focus. That raging hunger will also cause you to binge unnecessarily, and whatever carbs you don’t use will get stored as fat.

If your blood sugar is yo-yoing throughout the day, you’re never going to feel stable, dependable energy, which makes fasting quite difficult. This is where a ketogenic diet comes in.

Why keto and intermittent fasting accelerate weight loss

keto intermittent fasting weight lossOn a keto diet, you stop eating carbs and replace them with plenty of fat. After a few days of eating very few carbs, your body becomes efficient at burning fat for fuel. You walk around in fat-burning mode all day, enjoying a few benefits unique to keto.

  • No cravings. Fat doesn’t spike your blood sugar levels. In fact, a keto diet is so effective at stabilizing blood sugar that it got type II diabetics off their medication entirely, according to a recent study.[15] If you pair a keto diet with fasting, your blood sugar will stay stable and low (but not too low) all day. Say goodbye to the cravings, fatigue, and mood swings that make high-carb fasting so difficult.
  • Hunger suppression. A ketogenic diet suppresses hunger, too.[16] On a keto diet, your liver turns fat into little bundles of energy called ketones, which it then sends through your bloodstream for your cells to use as fuel. Ketones suppress ghrelin, your body’s main hunger hormone.[17] High ghrelin makes you hungry. On keto, your ghrelin stays low, even when you don’t have food in your system. In other words, you can go longer without eating and you won’t get hungry. Fasting becomes significantly easier on keto so you can fast for longer windows to reap all the benefits.
  • Fat loss. Keto and intermittent fasting are a one-two punch for losing weight. Fasting and keto both spontaneously increase fat loss, even when people don’t intentionally restrict their calories.[18][19] When you pair intermittent fasting and keto together, you become a fat-burning machine. The weight comes off quickly, and because keto also suppresses ghrelin, you don’t get nearly as much of the hunger and feelings of deprivation that usually accompany weight loss.

Download your free Keto Recipes for Beginners ebook & Keto Meal Plan

Choosing the best intermittent fasting schedule for you

how to intermittent fasting scheduleFasting is an extraordinary tool for high performance. There are a bunch of different ways to do keto intermittent fasting:

  • 16-hour fast (aka 16:8): The most popular type of intermittent fast, the 16-hour fast encourages you to eat all of your meals in an 8-hour window, such as noon to 8pm. To activate the full benefits of intermittent fasting, try an 18-hour fast, once you’ve adapted to 16 hours. This would mean eating between noon and 6pm or between 2pm and 8pm. Simply avoid eating after dinner, and skip breakfast in the morning. Limit carbs to dinner.
  • One meal a day (OMAD). Eat one big meal day, whenever feels best, and then fast the rest of the day.
  • Weekly 24-hour fast. Take one day a week, preferably on the weekend, and skip food entirely.
  • Alternate-day fasting. Go back and forth between feasting days and fasting days. Eat like a king or queen one day, then eat nothing the next. This will probably be the most challenging fasting option for most people. If you try it, make sure you’re eating a ton on your feast days, otherwise you’ll fall into a major calorie deficit and you’ll likely feel miserable.

Most folks do well with daily 18-hour fasts, but the other choices may work better for you. Experiment and see how you feel.

Intermittent fasting and keto are the perfect pair. If you want to make both of them even easier, try Bulletproof Intermittent Fasting, which incorporates Bulletproof Coffee into your fast for increased mental clarity and even less hunger.

And if you want to get started on keto, check out this complete beginners guide to a ketogenic diet.

Try combining keto and intermittent fasting and see how you feel. For more tips and hacks on bolstering your performance, sign up for our newsletter below.

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