I have recently started personally experimenting with different fasts and protocols after reading and seeing the science and benefits prominently discussed. However, my wife is skeptical.
I have been able to share with her many reputable sources which discuss the many benefits (and potential human benefits based on on animal studies). However, her skepticism comes from the fact that we all have quite some confirmation bias and tend to be in certain bubbles. e.g. if your inclined to like veganism all you’ll see in google searches, instagram, reddit etc. is why veganism will save you and the planet. (Just an example, no hate for vegans!).
TL;DR - So what I would like to share is an honest list of the actual risks and potential adverse effects that have been found in research on fasting so that I can share a balanced and ‘credible’ assessment of risk/benefit. Do you all know of such a source or a collection of well regarded human studies?
A risk is electrolyte deficiency but you can counter this with electrolytes of course. An adverse side effect is lowered testosterone after 8 days of water fasting. This is due to your body being in survival mode and not prioritizing the standard hormone functioning. However this is not really a noticable problem for people with normal testosterone levels and it will return back to baseline after the fast is done.
I don’t have any sources but I would say a danger is creating an eating disorder. I love the mental clarity in the morning but I do find my emotions can become an issue when pushing through hard periods. This can be taxing while working a stressful job. I try to be aware of how I feel.
Depending how long you do an extended water-only fast, there can be a potential danger when fast is broken. I think it’s called refeeding syndrome. (?not sure? ?something to do with phosphorus?) It occurs Rarely but it IS a life-threatening condition. I believe with a google search you will be able to find the details. This Risk can be managed/lessened by taking care with beginning to eat again.
With less-extended fasts you can get gastric upset when breaking the fast. You can potentially get cramps, muscle spasms etc – OR muscle issues Might be Lessened instead. Electrolytes are important. It is really important to Include electrolytes/minerals with your “water-Only,” or you can be at serious risk of dehydration, depending on the length of the fast.
Also depending on Length of fast, there could be risk of vitamin deficiencies. Most folks do not really need the large quantities of all vitamins normally found in supplements. But there could be risk of vitamin-deficiency with some fasting. So IF extended water-fasting, might be a Very Good Idea to get bloodwork done on a moderately frequent basis, and supplement with vitamins somehow if needed.
Simply the electrolyte issue. This is because ketosis has a diuretic effect (your kidneys use salt to transport water out of your body). A dash of Redmond real salt or similar pink salt under the tongue or in your water will keep you safe.
Prolonged fasting (2+ days) can worsen immunity response (temporarily - once eating is resumed, the immunity system might be stronger than before), which is unfortunate with covid :( I remember reading multiple articles on that but off the top of my mind it was mentioned in the Zero app too https://www.zerofasting.com/fasting-and-covid-19/
I recently read 3 books, from Dr Fung, Dr Greger and Dr Campbell. There’s a lot of common information but also some contradictions, so I find it difficult to be able to consolidate everything with some conflicting views. However, I think those views are either minor or affect the extreme end of the subject (very very long fasts), in which case, none of their “opinions” matter more than your body’s.
(Unfortunately I can’t experiment on myself but it’s good reading in Covid times…)
Think of fasting as the ultimate keto diet. While you aren’t eating, your body is literally living off nothing but your own stored fats. This is perfectly healthy, how the body was developed to operate - this is why we store fat to begin with, to survive the tough winters and when we suck at finding food.
The best source of information is probably the r/KetoScience forum. Understand that the specific “keto diet” is focused on eating fat and protein and basically extremely low carbohydrates but when you don’t eat at all your body reacts EXACTLY the same way as someone on keto. Only much faster and to a higher degree (to keep you alive). Learn about the biochemistry.
The first half of a woman’s cycle (approx two weeks from start of period) is the best times to fast/eat low carb. In the second half our bodies need carbs for hormone production. Its best to include healthy carbs in this time otherwise your body will crave unhealthy carbs that’ll give it a quick spike. This is also how we can negatively affect our hormones by “pushing through” when our bodies are trying to tell us something.
Apparently not having ypur gall bladder empty for extended periods can lead to or increase gallstone formation. In researching this I only found one article about it. It stated that ingestion as low as ten grams of fat will cause the gall bladder to empty. One question I had after reading the study was total amount, as they said ten grams would empty it, but research subject received three doses of ten grams of fat with their highly controlled meals. My questions would be could one simply take ten grams once a day, would thirty grams once a day be better, and how much would this affect one’s fast (read an article by Dr Fung wich stayed fat in isolation has no effect on insulin levels; how does this affect autophagy, etc?)? My apologies if these leaves anyone with more questions than answers.