Fasting by Science.
What it is, how it’s not like dieting, kinds, what’s allowed, top hacks to stick with it.
Fasting, intermittent fasting, time restricted eating, 16:8, 5:2, fasting mimicking diet or FMD, fasting for fat loss, fasting as anti-aging, fasting to build muscles, fasting for brain, heart and gut health.
Fasting, fasting, fasting…
You have probably read at least one article or some post on social media about fasting, some scientific research, celebrity weight loss and body transformation show case, your friend’s brag about how fasting changed his life.
Fasting is as ancient as philosophy and Bible, probably even more ancient, just nobody talked about it back then. It was a part of our daily lifestyle, forced by lack of food that was quite an often occurrence.
Fasting VS Starvation VS Low-Calorie Dieting.
Fasting has probably 2 main features, that makes it different from starvation and low-calorie dieting.
Fasting is (let’s put aside all the different kinds of fasting for simplicity for now), fasting is a restriction, total restriction or partial, of nutrition for the purpose of improving one’s health, metabolism, lose our stubborn fat, rejuvenate our body and mind, prove ourselves, that we are tough enough and our body can indeed burn its own fats for fuel.
It’s done voluntarily, and we define when we start, how we do it, when we finish. Nothing and nobody forces us. We are in charge of this, often miraculous, experience and transformation.
Starvation, on the other hand, true starvation is a complete or partial (in case of a low-calorie diet) deficit of nutrition in one’s diet. It is usually not planned, has no specific goals, is not done for health reasons, usually forced, have no specific time frame, it’s forced on us, usually by outside forces (or ourselves, when we don’t know better).
Fasting has an intermittent nature.
We fast. Then we don’t. Then we might fast again soon. In the case of intermittent fasting (even though I’d argue all fasting is intermittent, it’s not like you do it once in life and you are done), fasting is done more often for shorter periods of time, and then there are fasts, that are longer, few days or weeks, that we don’t necessarily do on a regular basis but more when needed, and when we feel like it.
Fasting needs to be combined with periods of sufficient eating, when we provide all the necessary nutrition our body needs, a VITAL piece that eludes many, even in a health conscious community. For fasting to give you benefits — you need to have feasting times, that involve eating a lot of NUTRIENT-dense foods, not some junk, rich ONLY in calories.
Fasting. How can I do it exactly? What are different kinds?
As I’ve mentioned, fasting can be done very often, intermittently, daily (let’s say 16, 18, 20 hours of not eating with a shorter eating window). It can be done weekly for a day, 24 hours, 36 hours, it can be done for several days once in a while, 5–7 days once in a season as many people do, it can last a few weeks, when people feel they need to have a real health restart, or their body really needs it — to restore metabolic health.
Very popular fasts are daily fasts of 16 hours with 8-hour eating window, that is done by many healthy eating enthusiasts, many people in low carb and keto community, by people into a lot of training, reaping the benefits of increased growth hormone release and adrenaline, that together help to build lean muscle, burning fat for fuel.
5:2 fasting protocol is another popular one. That is about eating normally for 5 days, whatever that normal means for people, and then restricting calories to 500–600 a day, for 2 days a week, popularized by UK TV personality Michael Mosley.
Then there is a 5-day fasting mimicking diet, popularized by longevity researcher PhD Valter Longo (My blog post, book review of the longevity diet and lifestyle, fasting mimicking diet, is still the most popular blog post on Medium). Basically FMD (fasting mimicking diet) is a low calorie, low protein, low fat (basically low everything) 5-day eating protocol, 700–800 calories daily, diet designed to lower and maintain low insulin levels, as well as stimulate autophagy, or self-eating of our cells, eating old and dysfunctional cell structures, making us stronger and more robust, rebuilding everything anew, once we start eating nutritious meals again.
Fasting. What do I eat now?
Traditionally you won’t consume much during your fasts. Duh…
Water, non-caloric teas, herbal, green, black, black coffee, maybe some minerals and electrolytes, when needed. For longer fasts people might choose to consume something like bone broth providing some collagen, traces of amino and fatty acids, sodium, other electrolytes.
Fat fasting also got some popularity these days with all the high fat and low carb people, all the bulletproof coffees consumed. Fat fasting is when people would consume some amount of pure fat in the form of bulletproof coffees or teas, adding a tea spoon of coconut oil or grass-fed butter, or ghee to their drinks, to help their body and brain adjust to fat burning and still get some nutrients to not feel completely deprived. Personal experience and opinion: fat fasting (unless you eat hundreds and thousands of calories, that cancels all the fasting), the effects of it are more psychological than physiological. It does cancel some beneficial effects of fasting, when it comes to autophagy, cell rejuvenation, fat loss. But on the other hand, fat has the least effect on insulin levels compared to other “fasting food” choices, and it is probably the only nutrient, in small amounts, I’m ok with when fasting. Plus non-caloric teas and coffees, water of course.
Sweeteners?
A no-no. Sorry guys.
Not stevia, not whatever fancy sweetener you got from some advanced supplement company you love.
No. Sweet. Taste. Period.
It’s proven to have an effect on your insulin levels and hunger levels (increasing it) one way or the other, through your brain signals or via gut microbiome.
Individual responses vary of course, but there is still a negative effect, when it comes to sweeteners and fasting.
Some people think (you are not one of those people, aren’t you?), that copious amounts of heavy cream, Mcts, grass fed butter and stevia kind of bulletproof coffee is a normal part of a fast — you could as well have a meal with such a recipe.
You are either fasting or you are not. Fat is not some magical nutrient, that puts your body into fasting state. You need restrict calories. You need NO sweet taste. No protein either, since even small amount of amino acids stimulates mTor pathways, canceling all cell rejuvenation, effecting your insulin too.
YES: tea, coffee, water. For longer fasts: bone broth (homemade), minerals and electrolytes, vitamins. For fat fasting: small amounts of fats allowed.
NO: sweeteners and amino-acids. And everything else of course.
The exact fasting protocol will depend on:
- Your goals: fat loss, gut, brain and heart health, type 2 diabetes, metabolic syndrome, longevity etc.
- Your health
- Your fasting experience
- Your lifestyle and life demands: don’t design your life around fasting — design your fasts around your life to stick with it
My top tips on sticking with it. How to actually do it.
Get busy. One of my clients did this neat trick. He put a to-do list on his fridge, with some activities he never seemed to get to doing. Every time he was about to reach for food, when we was not supposed to, he would see the list, pick the activity and go on doing it. By the time he would finish, the hunger would either completely disappear, giving space to renewed motivation, or it would be much less noticeable and much more manageable. I still believe this is the smartest fasting hack I’ve ever tried and advised ever since. Most of our hunger is in our head, in our mental urges and cravings — not in our body, as you might think.
Get away from food. Really important! People think (I used to think that, until it failed me every time), people think, that talking about food, watching cooking shows, looking up recipes, watching someone eat, food smells — all that doesn’t influence our decision to eat or continue fasting. Ha-ha. You probably haven’t fasted much successfully, have you? I’m not blaming you! The more food cues, food triggers your mind notices — the less of a success rate your fasting practice will have. When you think about it — you’ll end up eating it.
Get drinking. No, not that kind of drinking to ease the pain of fasting 😊 Warm non-caloric liquids, herbal teas, regular teas, black coffee, warm water — all that keeps your mouth and stomach busy and filled. Also, that warmth in your mouth and your stomach has some calming and satisfying quality to it. It’s gonna be much easier to fast, constantly sipping that warming liquid. Green tea helps especially well — proven by fasting authors, studies, fasting facilities, helps to decrease hunger and utilize your own fats for fuel. Plus, think about all the anti-oxidants and potential anti-aging effect!
And last but not least. Not so many people talk about that, when it comes to fasting, but — it’s VITAL to eat nutritious and good quality diet, when you are not fasting. If you are constantly under-eating and are malnourished, because you eat poor quality diet, undereating proteins, essential fats, micro and micronutrients — forget about it, your body and mind will struggle and fight you, literally till your last breath! Starving yourself ALL the time never gonna work — that’s how you end up fasting till night and binging like a pig on everything and anything you see before bed, like it’s the last food you will ever eat. Don’t do that. It’s stupid. There is nothing healthy about it. I’ve done it. It’s stupid. It doesn’t work.
This is what I’ve learned (and so much more) reading “The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting” by Dr. Jason Fung, and other books, and tons of articles — everyone seems to be talking about fasting these days. Plus my own decade-long personal and professional experience.
Here are a couple more links for you, if you want more video or audio information from yours truly on the subject of fasting.
Every resource provides slightly different information, a bit more of this, a bit more details on that.
Plus, TUNE IN to this amazing episode of FOOD SCHOOL Smarter Stronger Leaner podcast I did today to get my top advice on learning how to eat to support your weight loss goals and increase the benefits of your regular fasts.
HAVE FUN FASTING!
