Thats been my experience too, along with undesired weight loss, even just doing 14-16 hours. What is your take on very lean body builders who fast to increase growth hormone levels? They seem to be OK from an energy perspective…from what I have seen them say anyways.
Dave I was wondering how Richard’s calculator dovetailed with your fasting disaster… it seems to uphold the prediction that you would feel bad because you don’t have enough body fat to draw on to meet your energy needs.
Actually, it’s funny you brought that up as I’ve been asking a few that I know about it. One brought up that food in general is just “part of the process” of training to get cut, particularly toward the end. All of them said they don’t like that part of it, but quell their frustration by promising themselves the post-competition bad food binge. (So, so many things wrong with this)
I’ve asked every single one (3 total) “do you find you have more energy, less energy, or about the same?” One said about the same, but couldn’t be sure. One said less, but not so much she couldn’t power through it. And one said less “explosive energy” – but he was extremely happy with how he looked, so it balanced out the “general bleck” feeling of the diet.
I really suspect this to be the case. And I don’t think I’m insanely lean either – probably around 18% bf right now.
However, just like not all lean muscle mass is treated the same metabolically, I’m seeing more and more evidence that this goes likewise with body fat (and in particular, subcutaneous fat). That there’s a thriftier pushback on lipolysis that occurs the lower you go, and this may be very individual.
Years ago when I was even leaner than now but much less muscle (maybe 145lbs at 5’9) I tried a 3 day fast for some ungodly stupid reason. By the second day I felt like absolute death. Needless to say I stopped. It wasn’t just hunger, I felt completely sapped of energy. It all makes sense in light of this and similar threads. In fact it seems like many lean low-carb people who try more than IF feel terrible. I have no trouble doing 16-18 hours fasting, but I don’t think I would ever try a straight water fast for 24 hours or more.
That would fit my n=1 experience, which is that it can be hard to fast without supplementing with fat at my current weight (~187 at 5’-10", approx 20% BF). I can definitely tell when I hit the wall where the extra circulating energy from feasting has been used up. Where things go south is if I don’t respond to that signal by increasing fat supplementation significantly.
And again, I have to emphasize that it was a feeling unlike anything I’ve had before. I’m extremely disciplined about sticking things out once I’ve committed to it (not that I need to tell this audience) – but this dark, terrible feeling was the kind I felt was a new level of serious. Like when you’re a kid and you’re playing with something extremely dangerous that your subconscious knows is a Bad Idea, but your kid-like curiosity is trying to overrule.
I described it to a friend recently as that sensation of being very close to the edge of a cliff that you think has a very short distance of a drop until you’re up to it and realize it’s much further, then slipping just a little bit and feeling extremely afraid of what almost happened. A fast acceleration of realization in the seriousness of the situation while getting a raw dose of fear at the same time. That’s my best analogy for the feeling I have so far.
Do you find that the fat supplementation works to boost energy and overall feeling of well being during your fasts? At 5’8" 150 lbs, I don’t need to lose any more weight but am interested in fasting for the autophagy and potential cancer prevention benefits.
I don’t know that I have enough experience to say for sure. I know it mitigates the difficulty I have with fasting longer than 24-36 hours without.
I also find there’s some variation. The last time I attempted an extended fast, I got the feeling pretty quickly (within 24 hours, IIRC) that my body was telling me it wasn’t the right time to fast.
I don’t know that I’ve ever felt what @DaveKeto describes, though the last day of my Holy Week fast, which went around 5 days, was pretty close. Mostly, when I have gone beyond what my body can provide, and I’m not supplementing enough fat, I get cold and weary feeling.
When a fast is going well, I do sometimes get bursts of hyper-productivity. That’s usually sometime in the first 1-3 days. I’ve not gone longer than a week, so I don’t know what that would be like, though I am pretty sure I’d have to supplement fat to make it that long.
I’m sub 10% BF. I don’t consider consuming fat actual fasting, but I only consume fat (no carbs or protein) for the majority of the day, around 15-16 hour window. I feel absolutely fine, high energy. My blood sugar at the end of this window is usually around 45-55 and ketones very high (red zone on breath, around 3.5 blood).
So, I do very well on “fat fasts” while being lean. But straight fasting makes me lethargic…which if I want to rest and unwind, can actually benefit me. On vacation for example. But consuming fats keep my energy very high.
Could you give us an idea of what fats you eat and how you ingest them please?
Here is an example from yesterday. After consuming nothing but fat for about 14 hours (about 800 calories worth of fat) my blood sugar was 53 and I was 80 (red zone) on ketonix. I was physically exhausted from a my day (10 hour nursing shift, lifting session beforehand), but my mind was on fire. I tried to lay down but felt “ansty” which is usually how I feel when my ketones are high. So I got up and did computer work. Before keto, I would immediately knocked out and fell asleep after a long day of physical work.
I’m curious as to what your 800 calories of fat consists of, too .
Sorry @richard this may be a bit off-topic for the original post, but your mentioning NEFAs reminds me of something I still haven’t fully got my head around, despite having studied LCHF diets, and more recently keto, for some time.
I believe that NEFAs and FFAs (Free Fatty Acids) are one and the same thing, and Wikipedia has just reminded me that the “free” does not mean that they are literally free-floating in the bloodstream, because they still need a “transport protein” (Wikipedia mentions albumin, but I think it could be other things (chylomicrons, or example?).
Anyway, these NEFAs or FFAs are, in principle, available for metabolism, i.e. are available as fuel. One of the things I learned (or thought I had learned) from Gary Taubes’ magnum opus “Good Calories, Bad Calories” (on my many readings/re-readings of it, over several years) was that the presence of FFAs in the bloodstream was a good thing, from the LCHF point of view.
However, from time to time, I see things from more mainstream sources implying that a lot of FFAs in the bloodstream is a bad thing.
Here, for example:
Would you care to comment / clarify my thinking in this area @richard?
Yep, same thing. The esterification of fatty acids just means they have been bonding to an ester to make an acylglycedride - and usually we have 3 bonded to a glycerol make a triglyceride. It’s the storage form of fatty acids, and the NEFA form is the ready fuel version.
Non-esterified fatty acids aren’t as you say freely roaming as they have to be ported about by proteins. So Non-esterified fatty acids is a more accurate description than Free fatty acids.
Our fat burning cells get them from 3 places;
From inside massive lipoprotein particles called chylomicrons carrying triglyceride from the gut … will dock with the cell and they will use an enzyme called lipoprotein lipase to break a triglyceride into it’s 3 NEFAs and they are transported into the cell.
From inside Low density lipoproteins carrying fat from the liver, much the same process happens to extra a triglyceride out.
Finally when energy in circulation drops, fat cells release NEFAs bound to sheets of protein called albumin and that also carries the NEFAs through the circulation to any consumers. When glucose comes into the system, insulin goes up and that inhibits healthy fat cells from releasing NEFAs into the blood stream. When insulin drops, the fat cells start releasing NEFAs again. That is the daily switch between the fed and fasted state. Insulin going up or down based on when you eat determines if health fat cells release energy.
That is the one Gary Taubes was talking about, when he talks about NEFAS in circulation it’s the supply of energy from adipose when glucose is low, to a system that is good at burning fat. That is pretty much Keto perfection in a nutshell.
The problem identified in that paper is a description of what happens when the adipose no longer can store any more energy - which is adipose insulin resistance. The pancreas produces more insulin when there is fat in circulation (to try to get NEFAs out of circulation) when glucose is about - that’s one of the drivers of increasing pancreatic over production of insulin, NEFAs and Glucose both in circulation.
Why this is a problem, we have to go down to the level of the cellular consumers of that energy. We have a switch at the mitochondria in our cells where insulin inhibits us being able to quickly get fats in to be burned (the carnitine shuttle). When we have both NEFAs AND glucose (and therefore insulin) in abundance then we burn the glucose and the NEFAs build up in lipid droplets in our cells. Eventually that interferes with the ability to get glucose transports to the cell wall … and that is cellular IR in action.
I could be wrong about all that … but that is my understanding. Hope it’s helpful.
Wow, thanks for such a rapid and comprehensive reply!
Will have to re-read (especially the last 2 paras) a few times to make sure I’ve got my head around it, but yes, very helpful thanks Richard.
I just found this thread on this forum and I must say it is the most well-informed, comprehensive, and scientifically based discussion around. Perhaps someone could help me. I am a rather obese (50# overfat) menopausal woman who is extremely metabolically healthy. I have great cholesterol levels, FBGL in the mid 80’s, excellent blood pressure, and ALL extensive blood work was normal except slightly low white blood cell count and slightly low body temperature. However, I and my mother and sister ALL have slightly lower body temperature for all of our lives. My white cell count has ALWAYS been slightly low for years and years. I rarely if ever get ill. No allergies or autoimmune issues. I have been getting migraines for many years. Sometimes very severely. I have had MRI’s, blood work and ALL are negative. In saying ALL of that, I want to try fasting for several reasons: religious, weight loss, autophagy, and to deal with a binge eating disorder that occured after a long deployment. I made a 24 hour fast with no hunger or temptation issues. I DID vomit, get a migraine, and had diarrhea. I suspect that was lack of caffeine from reduced coffee intake. For those of you who are still with me my question is this: I REALLY want to induce autophagy without losing lean body mass, yet in a talk by Dr. Stephen Phinney he emphasized that LBM would decrease at fasts over 48 hours. That was actually the longest I planned to fast anyway but will I be able to induce autophagy in that short of time period given that I am probably NOT fat adapted and am a carb burner? I have other questions regarding hormone regulation specifically thyroid, leptin, the hypothalamus and pituitary but I shall save them for later. Thanks to anyone who would answer this long post!!
There’s a great thread about Dr. Phinney and fasting here. Lets just say there is much disagreement with his extrapolation of numbers.
Dr. Jason Fung’s main purpose for fasting is to reduce insulin and this is accomplished by avoiding foods that raise it such as carbs and then protein which is stimulated at only 50% of the rate that carbs stimulate insulin. Fat has an absolutely minimal effect on insulin which is on par with the gut-stretching effect of eating rocks raising insulin, but it is possible to over-consume fat to some degree that it affects insulin if someone is Insulin Resistant (IR).
Dr. Ron Rosedale’s take on reducing protein and indirectly on fasting (which would inherently reduce it) is to avoid stimulating MTOR (Mechanistic/Mammalian Target of Rapamyocin) because it is growth pathway and is the opposite of autophagy.
Autophagy is mainly stimulated by the absence of carbohydrates and the absence of protein, where the body is primed to start scavenging from itself as cleanup, so consuming fat for the body’s basic energy requirements would be “fat-fasting” and you can find talks by Dr. Valter Longo for more details on his Fasting Mimicking Diet (FMD), but many people have inferred that eating some fat, and perhaps fiber-carbohydrates from things such as avocados with absolutely minimal amounts of protein will still allow the body to enter autophagy.
The main problem with a general recommendation for fat-fasting is some people over-indulge in adding fats to coffee/tea for example, or they add sweeteners of some kind that stimulate insulin. I’ve personally tested my response to sucralose and I’ve indirectly determined that it releases insulin, so I can’t use it during any fasting that attempts to do anything more than just reduce calories, which is not my main goal since I fat-fast for autophagy and to maintain my T2DM reversal.
I’ve recently started experimenting with including AMPK Activators such as berberine to my fat-fasting regime, and so far I like the results.
There may be other objective criteria such as fasting insulin levels, but the closest thing I have is the Glucose Ketone Index (GKI) where anything under a ratio of 1:1 is considered an excellent fasting indicator and even before adding berberine my fat-fasting GKIs have always been under 1.0 and adding berberine has only improved them.