Intermittent fasting, commonly referred to as IF, has become all the rage lately, and it doesn't look like the trend is going away anytime soon. The practice of intermittent fasting, or time-restricted feeding, is when a person limits the period of time in which they consume calories down to a limited number of hours. So for example, I practice IF with an eight-hour eating window, which means that I will only eat between the hours of 12 p.m. and 8 p.m.
Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though people struggled with the fasting days. So I had written off IF as no better or worse than simply eating less, only far more uncomfortable. My advice was to just stick with the sensible, plant-based, Mediterranean-style diet.
Black coffee won't break your fast or take you out of ketosis. In fact, according to a report published in the Journal of Basic and Clinical Physiology and Pharmacology in 2017, caffeine may even increase your metabolism, which will help promote weight loss. Black coffee also helps curb your appetite, which can make getting through your morning fast much more manageable.
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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.
Fasting on keto can be incredibly beneficial, especially if you’ve reached a plateau and aren’t seeing results from the ketogenic diet alone. While it’s not required, keto intermittent fasting can bring the benefits of your diet to the next level and help optimize your health. It is also thought to speed up ketosis by helping your body burn through glycogen stores more quickly, which can help sidestep symptoms of the keto flu to get faster results.
Mackenzie has worked in several branches of a very popular national chain of coffee shops and has experience with customers trying to comply with a variety of diets. Keto, Whole30, Vegan, and many more. She says that she and her staff have learned a number of tricks to help customers who struggle with switching to black coffee after drinking their favorite “Large Caramel Cappuccino with Whipped Cream” for years!

Harvard-trained physician and author of The Paleovedic Diet, Dr. Akil Palanisamy further explains to POPSUGAR that "autophagy is the self-cleaning process by which the body's cells break down and recycle damaged proteins and components. This is activated by intermittent fasting, but anything other than water (even black coffee) disrupts it to some extent."
Hi Tade, there are benefits and pitfall in training in a fasted state. Though fasted training may push your workout routine to the next level, always listen to your body to make sure it’s not suffering. If you’re used to high-intensity workouts, fasted training might not be for you. For more info, you can check out this link: https://perfectketo.com/fasted-training/
As a lifestyle-leaning research doctor, I needed to understand the science. The Obesity Code seemed the most evidence-based summary resource, and I loved it. Fung successfully combines plenty of research, his clinical experience, and sensible nutrition advice, and also addresses the socioeconomic forces conspiring to make us fat. He is very clear that we should eat more fruits and veggies, fiber, healthy protein, and fats, and avoid sugar, refined grains, processed foods, and for God’s sake, stop snacking. Check, check, check, I agree. The only part that was still questionable in my mind was the intermittent fasting part.

This content is strictly the opinion of Dr. Josh Axe and is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of medical advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Axe nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement or lifestyle program.
Fasting 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.

Before you start your IF plan, it's important to talk with a professional to make sure it's right for you. Women should be especially cautious as there are some mixed opinions on whether or not certain fasting protocols are healthy for female hormone balance. In addition, if you have adrenal fatigue or gut health issues you'll want to proceed with caution. If you have a history of disordered eating, you'll probably want to avoid fasting altogether..


Since all of your hormones are so deeply interconnected, when one hormone is thrown off balance, the rest are also negatively impacted. It’s like a domino effect. As the “messengers” that regulate nearly every function in your body — from energy production to digestion, metabolism, and blood pressure — you don’t want to disrupt their natural rhythm.
Your body contains proteins and other structures that constantly become dysfunctional or die. This isn't a bad thing; it's a necessary process for optimal health. However, if these dead tissues aren't cleared out from the body, they can cause cell death, contribute to poor cell and organ function and even become cancerous. Enter a process called autophagy.
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To make “down” days easier to stick to, Johnson recommends opting for meal replacement shakes. They’re fortified with essential nutrients and you can sip them throughout the day rather than split into small meals. However, meal replacement shakes should only be used during the first two weeks of the diet — after that, you should start eating real food on “down” days. The next day, eat like normal. Rinse and repeat! (Note: If working out is part of your routine, you may find it harder to hit the gym on the lower calorie days. It may be smart to keep any workouts on these days on the tamer side, or save sweat sessions for your normal calorie days.)
Articles and information on this website may only be copied, reprinted, or redistributed with written permission (but please ask, we like to give written permission!) The purpose of this Blog is to encourage the free exchange of ideas. The entire contents of this website is based upon the opinions of Dave Asprey, unless otherwise noted. Individual articles are based upon the opinions of the respective authors, who may retain copyright as marked. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the personal research and experience of Dave Asprey and the community. We will attempt to keep all objectionable messages off this site; however, it is impossible to review all messages immediately. All messages expressed on The Bulletproof Forum or the Blog, including comments posted to Blog entries, represent the views of the author exclusively and we are not responsible for the content of any message.

There is a reason that you crave fatty and salty foods when you’re stressed – adrenal exhaustion. Listening to your body, then eating something soaked in grass-fed butter and coated with high-quality salt gives your adrenal glands what they need. Higher overall fat intake combined with a sprinkle of pink Himalayan salt can do wonders for adrenal function.
Those studies above, in working with small sample sizes, and different types of fasting than recommended here, would lead me to believe that fasting affects men and women differently, and that many of the weight loss benefits associated with intermittent fasting (that affect insulin and glucose responses) work positively for men and negatively for women.
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