I am curious about why longer fasts would be more effective at achieving goals like reversing IR and losing weight. I understand that those who do longer fasts gain back some of what they lose. Wouldn’t a more sustainable approach be to IF daily and eat a keto meal at the end of the day? It seems that after a while longer fasts might take their toll psychologically. I’d like to see studies comparing the effect of more frequent, shorter fasts and those of less frequent, longer fasts while utilizing a keto diet. (I know they don’t exist just wishing I could see them!)
Why are longer fasts more efficacious than daily IF?
collaroygal
(KCKO, KCFO)
#2
Megan Ramos mentioned extended fasting vs. IFing in one of the podcasts, can’t remember which one, but she said for some people the IFing protocol works just as well as the extended protocol. It just takes people longer to lose the weight with IFing than extended fasts.
Emacfarland
(Erin Macfarland )
#3
Yeah I heard that episode, I just wondered why and if there is any fallout from continued extended fasting.
steak
#4
A few things come to mind.
First there’s the obvious eating fewer calories. So weight loss is faster.
Metabolism goes up after a day or two, from the norepinephrine increase that happens. It does drop again after a few days.
It may take a while for insulin levels to drop enough to allow fat to be burned easily. This is something I noticed personally. I was naturally doing IF all the time anyway, but it wasn’t effective. I was also still eating a lot every day. While doing EF, the weight melts off.
EF is also good for autophagy. If I’m still eating protein, etc., my body won’t scavenge. I want it to recycle the skin I dont need.
The downside with EF is that electrolytes and micronutrients can become depleted. Your body will use up phosphorous and calcium from the bones, for instance. There is also the danger of refeeding syndrome.
4dml
#5
I’m no scientist, but it seems EF is more efficient at repairing IR because of the greater time spent with low insulin levels. In folks with extreme IR, an IF window of even 23 hours might not be long enough for insulin to drop significantly. Furthermore, EF creates a hormonal environment that promotes fat loss while preserving muscle mass, according to Dr. Fung.
In terms of sustainability, there’s no comparison. EF by definition isn’t sustainable. It must come to an end, be it measured in days or months. It’s not a long term WOE.
I don’t think that intermittent EF (ie. 3-4 days every month) is very effective for weight loss because most of it likely to be water that is regained. While weight loss associated with an IF WOE is likely to be fat loss.
I don’t think the 60 lbs that I lost in 3 months via EF, would have occurred as rapidly with IF. My BG spends most days in the 55-70 range, allowing my pancreas to rest, my muscles to up regulate glucose receptors, and efficient lipolysis. If my BG rises to 100 after a meal, it takes a couple of days fasting to get it back down, an IF window wouldn’t be sufficient time.
I think of EF as a tool for achieving a goal (weight loss, cancer prevention, improving IR, curing a host of diseases) that then allows you to get on with your WOE (ie. vegan, HFLC, Paleo). I think of IF as a tool that improves upon any WOE.
Emacfarland
(Erin Macfarland )
#7
What about when someone is insulin sensitive with no metabolic issues and at a healthy weight? Are extended fasts more beneficial than IF?
steak
#9
There are two reasons I can think of why EF is better than IF for a completely healthy person:
Autophagy. If you’re only doing IF, your body has no need to clean, repair, or recycle damaged tissues and protein, since new material is always around. I plan to do one or two week-long fasts per year once I reach my target weight for this reason alone.
Human Growth Hormone. Grow muscle and bone. Kicks in after a few days of fasting.
Emacfarland
(Erin Macfarland )
#10
@4dml I guess i meant to specify when I am referring to EF I am talking about doing longer fasts (2 days or more) indefinitely, rather than changing that approach when a goal is met (say, reaching a healthy weight or reversing disease). So when body fat stores are drawn down it becomes more difficult to fast for long periods. So for someone who is lean and wants go do extended fasts occasionally it would become necessary to supplement with fat to sufficiently meet energy needs since the body cannot provide all the energy one needs in a day from body fat because there is only a certain amount of energy that can be drawn from fat stores. When I was very, very lean I could not fast for longer than 20 hours or so because my body could not supply an entire day’s worth of energy from my energy stores. So perhaps fasting with supplemented fat would be an effective way to do slightly longer fasts while getting the benefits of autophagy and increased HGH levels.
bojana
#11
i think it depends on how many calories are being consumed during the if window eating time. i’m going to try doing only 600 calories during my if next time i do it. i was on a diet that only allowed that much i was under doctor care with b12 injections though and i lost a pound a day. i haven’t been paying attenion to how much i am eating during my if window but it’s not helping me lose weight anymore, it did in the beginning.
bojana
#12
my first meal doing the if that i saw weight loss with was just liver and onions fried in butter. the liver will give the fat and b-12 to keep us feeling sustained. idk if you want to try it, just throwing it out there but its not good to eat liver daily.
4dml
#13
I do not believe that healthy lean people cannot fast for extended periods of time because I’ve seen it done too many times. In my church, there are many people who fast one day each week (dinner to dinner) as a reflective spiritual practice. An organizated seven day group fast is conducted yearly. Someone else here posted that their church was doing a 30 day group fast.
Extended fasting has been done across cultures, going back to the earliest archeological records we’ve discovered. During most of that history, people were not metabolically deranged.
I can’t explain the science, all I know is that skinny people can and do fast. They lose weight temporarily, but they seem to suffer any ill effects long term.
marklifestyle
(Mark Rhodes)
#14
@Emacfarland I believe it will depend entirely on the person’s initial IR.
Your criteria is to improve insulin resistance and lose weight. let’s not then look to other healing factors like autophagy and HGH. Which then is more effective doing this an IF (23 hrs) or an EF (72 + hrs). During the IF you have ample glycogen stores to burn through before ever turning to lipolysis. If your insulin is high yet from your previous meal you cannot access your lipolysis. So it may just be that an IF is not as effective for beginners as it is for people who have a year or so.
During an EF, even from a SAD starting point, ketosis starts roughly on the third day. If you are Keto you gain this time by not having to wait for ketosis to begin. So that when your stored glycogen has run out ( I call this the glycogen wall and for me it is very real) and glycogen is demand driven through liponeogensis you can access your energy needs through using your fat “batteries”. I suspect though that protein needs begin to be addressed through the autophagic response as those freed amino acids that are salvageable can then be put to use to prevent lean body mass loss. On my and my wife’s EF of which we have done about 7- five or more days- since July 2017. The fat loss as measured by Dexascan correlates both to Richard’s 31 calorie per pound of body fat per day and Dr. Fung’s observation that about 1/2 lb a day is a typical loss on an EF.
to my mind then an EF is effective for insulin repair and fat loss for everybody at any time. An IF is great for insulin repair for everybody but likely will do less for fat loss.
@4dml I have been reading much of the Hygienists Movement prior to 1950. These societies included fasting for health. 21 days seems to be the point to which any person lean or not begins to become weaker. Up to 21 days most reported an increase in strength and vitality. I suspect the body does begin to cannibalize after 45 days or so. Whether Christian, Buddhist, Hindu, Muslim etc, the fasting length seems to be set about that 40 day mark.
ron-coleman
(I am a Dog (Dog's eat until they burst!))
#15
@bojana The idea of IF is not calorie reduction, it is to allow your body time to lower insulin and to repair itself. Reducing daily calories to 600 is still, pretty much, fasting.
IF gives you body time to use the nutrition you bring in and also do some house cleaning. Dr. Michael Mosley did a BBC documentary on the 5:2 diet in 2013 where people fasted 2 days a week, not always consecutive days, and lost a lot of weight. This is a good listen to understand more about short, medium and long fasts. There is also a book “The Fast Diet”
Emacfarland
(Erin Macfarland )
#16
I am wondering too how one would minimize weight gain after an EF?
marklifestyle
(Mark Rhodes)
#17
I weigh the same as before I started. I have changed body composition by 12%. I do not worry about gaining weight. My wife lost almost 60 and has stopped losing. The only thing that reassures her is the constant downward slope of the DXA and being able to finally buy clothes off the rack and having them fit.
Here are my scores from Pre holiday. Fat loss was 7 pounds in 2 months doing 2 5 day fasts.
steak
#19
I think you’ll always gain some. That is the natural way of things.
For me personally, feasting and fasting has been effective. I plan to keep doing it indefinitely. I am still a long way to my health goals though, so I can’t speak to what to do in maintenance mode.