After reading that headline, we're sure we've got lots of eyeballs and attention!
We want to start off by making things perfectly clear: Ketogenic Success never opposes fasting.....when it's done right.
What we are very vehemently against is diet mentality.
When it comes to any new idea or movement inside the health community (including all of us over here doing our low-carb thing) there is a lot of fad-ism and bandwagon jumping that happens. It seems no matter how many times we repeat that keto is not magic- and that you aren't going to find any formula you can follow exactly so as to wake up tomorrow looking like Wonder Woman or Captain America- people are still forever on the lookout for that one tip, trick, or technique that's going to turn what should be consistent and persistent long-term lifestyle work into fast-acting fat-burning wizardry.
Unfortunately, in our recent endeavors to educate people about things like carnivore keto and eating sufficiently to fuel our bodies, we still have a lot of people that see these things as a magic formula- maybe even the quick fix they've been searching for that's going to have them thin and fit overnight- and onto the bandwagon they go without really understanding what it is they're doing and why it may or may not work for them.
Fasting is a topic that has also gathered quite the bandwagon following, and understandably so. One of our own favorite experts, and the main spokesperson and proponent of the newest Aeitology of Obesity, Dr. Jason Fung is a strong and extremely vocal advocate for implementing fasting into a low carb lifestyle. He quite literally "wrote the book" on both Obesity and Fasting.
As has already been said, we here at Ketogenic Success have absolutely no problem with fasting, assuming it's done properly and for the right reasons. The problem of the bandwagon effect, however, goes right to the heart of what we've recently discussed in this space and the entire Ketogenic Success team find ourselves frequently discussing with our various group members and coaching clients: in essence, people are using fasting (unconsciously or otherwise) in an attempt to starve themselves thin.
Fasting for Health
Fasting is a wonderful health and wellness tool. It's been known as a healing technique- mentally, physically, and spiritually- for thousands upon thousands of years. With the advent of modern science, we now know why: the body handles intermittent periods of fasting in a way that is beneficial. When we spend significant, but occasional periods of time without food, it allows the body to rest. Insulin levels return to baseline, the digestive system and metabolism get a bit of a break from breaking down and using food energy, we burn off a little stored body fat for fuel, and the body begins a very healing process called autophagy, wherein old and damaged cells are either repaired, or destroyed and replaced altogether.
All of these are good things, and if you're fasting to try and gain some measure of healing for your body we absolutely encourage you to continue doing so.
If Fasting Is so Beneficial, What's the Problem?
As we see it, the issue isn't that people are trying out fasting, it's that, frankly, they might be doing it kind of wrong.
The key phrase in the explanation of fasting in the previous section is "significant, but occasional periods of time without food." As Dr. Fung himself has pointed out in his piece on the difference between fasting and a low-calorie diet, the body behaves in a different way when you are constantly feeding it a very low level of energy as opposed to when you fast for a few days, and then feed your body well on feasting days. What we are seeing is a lot of the former and very little of the latter.
The ideal way to fast, according to Dr. Fung, is to fast for longer periods of time- say a few days- and then spend a few days or more feasting (ie, eating really well) before beginning your next fast. The physical benefits and bodily reaction to longer-term fasting are as follows:
Fasting triggers numerous hormonal adaptations that do NOT happen with simple caloric reduction. Insulin drops precipitously, helping prevent insulin resistance. Noradrenalin rises, keeping metabolism high. Growth hormone rises, maintaining lean mass. Over four days of continuous fasting, basal metabolism does not drop. Instead, it increased by 12%. Neither did exercise capacity, as measured by the VO2, decrease, but is instead maintained. In another study, twenty-two days of alternate daily fasting also does not result in any decrease in RMR[resting metabolic rate].
Now, if you cannot do longer-term fasting, for whatever reason, and would prefer to do shorter-term intermittent fasting, it's OK... with a caveat. Benefits of fasting start to kick in around hour 11, so fasting for 12-18 hours each day can be fine as long as when you break the fast you are eating well and, on most days, are getting in sufficient energy to fuel your body. That last bit about sufficient energy is important because it is the "feasting" that we (and Dr. Fung) are always on about. However, when you are fasting every, single day and end up only eating one small meal most of the time, you are falling into what our own Coach Mary Roberts calls "The Low Calorie Trap." To quote Dr. Fung:
Caloric restriction diets only work in the short-term, before basal metabolism falls in response. This is sometimes called ‘starvation mode’. Daily calorie restriction fails because it unerringly put you into metabolic slowdown. It’s a guarantee.
We can't quote the entire blog post, but we do urge everyone to go read through it. The good doctor uses the very apt analogy of the difference between five straight days of a light drizzle versus three or four days of sunshine with a day or two of heavier rain. When you're fasting for long periods every day and then only eating a small amount in your eating window, your routine is like the days of light drizzling, and what ends up happening is you continually feed your body at a very low level and it is going to react as if you are on a low-calorie diet, because essentially that is what is happening.
However, when you are fasting and then genuinely feeding the body well during your feasting periods or eating windows, you manage to reap the benefits of fasting while also avoiding the drawbacks and pitfalls of eating at chronically low levels. The body does its fasting thing while you are, but it doesn't have a reason to slow the metabolism long-term because you're giving it a good amount of energy when you do eat.
The nutshell is this: As we have stated several times now, we do not want to encourage anyone to stop fasting, provided you are doing it for the right reasons and are making sure to fuel your body well when you are in your eating window. What we do want is to discourage you from using fasting as a tool for extreme caloric restriction, or as punishment for a mistake (or a cheat) of some sort, because the consequences to chronically low calories is a slower metabolism. We don't want that, and we highly doubt any of you is in the market for metabolic slowdown.
As always, every single person's body is different. Whether or not a fasting routine is going to be ideal for you at all- much less the frequency and length of your fasts- is going to depend on your own needs and goals. Some don't fast because they do not handle it well mentally, or they simply do not have a lot of hormonal damage they're trying to reverse. Many other people reading this are going to be all over the spectrum of fasting suitability, from those who don't fast well all the way to the fasting champs, and all of that is OK. The key takeaway from just about everything we put out for you is to identify the pros and cons, decide whether or not it applies to you, and then implement it (or not) in the way that suits you best.
Don't just jump on the fasting bandwagon- or the carnivore bandwagon, or the TDEE bandwagon, etc. and so on- because it's popular or people are talking about it. Don't even do it because you think others are getting results. Assess it for yourself and your needs, and if it fits you then you can make the leap!