Yes I read and listen to Jason fung as well. Unfortunately though, to me it seems that the two pieces of information conflict.
If there is a limit to how much fat energy one can mobilise, how can one’s metabolism speed up during a fast? What mechanism other than fat burning is supplying energy to fuel that increase?
I have never heard Fung say HOW metabolism increases during a fast, only that it does. And since I know he is deeply science based, I believe him.
The reasoning they always give is if metabolism slowed on zero food, humans would have died off in the cave man era.
Without having to digest food, we probably don’t actually need as much daily energy either.
Sorry I don’t have the science to explain it. These are all great questions.
Thanks for that, and of course Fung’s clinical experience shows fasting does work. I’m just doing my best to figure out for me what level of caloric deficit will have minimal impact to metabolism. I guess I’ll just need to experiment by having the appropriate amount of protein daily for lean muscle, and then just trying to keep my fat at a level below caloric maintenance. Trying 15% for now and that 15% should basically come from my dietary fat intake.
I’ve done 3 extended fasts total. My 3 day and 5 day ‘kept me going’ and I continued downward trajectory of weight loss (but I did have ‘more to lose’ at those times) and most recently my 7 day (most recent) I did gain back all the weight I lost and then added some additional back on. So I wonder if I did some slowing down to my metabolism during that 7 day fast. I guess it’s all about experimentation, maybe that level of prolonged fasting isn’t for me.
I decided at the end of that weight regain to just ‘reset’ and not do any prolonged fasts for some time, just try to really monitor macros closely and I did found I was likely going over 20g / day and probably overdoing it on calories as well. So I’ve been logging everything in to MFP to keep honest.
Question for any MFP users (or just general caloric trackers), when you exercise and you get ‘credit’ for the workout in calories (woohoo 300 more!) do you allow yourself to consume the additional food that day or do you try to ignore that ‘bonus’ and keep going with normal intake?
Technically, a calorie deficit is required to lose weight–unless you are hacking off limbs or surgically removing parts of your body.
What is questionable is the way that you create the calorie deficit. A calorie deficit can be created by eating MORE calories than you did before, as long as you also increase your burn rate. If you decrease calorie intake too much, you may lower your BMR, which could actually reduce or eliminate the deficit you tried to create.
This concept has been disputed though. The numbers come from some Ancel Keys study conducted on carb eaters if I’m not mistaken. Unfortunately it’s all we have to go on.
Stumbled upon this older thread:
Sounds like a fat-supplemented fast could prevent metabolic slowdown. I will definitely try one of those for my next extended fast this year to see if the dietary fat intake can balance out what I should theoretically be able to burn from my own stores.
The symptoms described by @devhammer with the cold are what I experienced on my recent 7 day fast. Devhammer did you since attempt this fat-fast? Anything you’d like to add since this post, any experiences to share for those trying to overcome the final crunch, where the advice that got us here while carrying a higher BF% isn’t quite getting us the rest of the way? Some caloric restriction seems like the only answer, but how much is the big question.
Since Keto is an ad libitum diet where you are supposed to eat to satiety, assuming your satiety signals work properly, I think getting hung up on calories is a dead end, tbh. We are not closed thermodynamic systems. What and when we eat seems way more important than how much.
Just anecdotally I had 1,200 calories one day, carbs at 20g, protein around 60, fat filled in the rest. The next day I had the same carb/protein macros but filled in with dietary fat up to 1,900 calories. Nothing happened on the scale. And I will keep mixing it up as Megan Ramos suggests. Falling into a predictable eating pattern can get you into a weight loss rut.
At this point in my Keto journey which started March of 2017, I’ve lost 40 pounds with about 20 or 30 left to go (female, 5’8”, 48 yrs old). I’ve been bouncing around the same scale weight since November but my clothes fit differently. I’m not exercising yet.
I’m Keto 100% of the time, I believe I’ve now healed my fat cells & they are working super efficiently, hanging on to their stores & keeping me stalled. From what I understand fat loss ability ALL depends on basal insulin level. And the only way to push your basal insulin level down after basically the six months any diet works, is fasting. How long you fast for effectiveness is highly individual and you will have to experiment as you said you will be.
As far as the exercise calories calculated on MFP I’ve always read they are wildly over stated, I ignore them. The most important thing about exercise re: Keto weight loss as far as I can tell is the increased mitochondria for fat burning. You cannot possibly burn enough calories exercising to make a weight loss difference. But you can make your body better at burning fat for fuel.
I don’t think that caloric restriction is the answer at all. That being said, I can’t claim to have found a magic bullet for “the final crunch” either. I have done some additional fasting, with fat supplementation, and the supplementation does seem to help with making the fast manageable. I’ve gone as long as 6 days, but I found that trying 2 cycles of 6 days back-to-back, with a feast day in between, did not work well for me. I think the next step for me may be trying some intermittent fasting, but the other important variable in my case is sleep consistency (or lack thereof). It’s pretty rare for me to get a full 8 hours of sleep or more, and occasionally I get less than 6, which is arguably a major contributor to keeping my insulin high, and preventing the remaining fat from going.
At the end of the day, I’ve seen enough convincing evidence that caloric restriction leads to metabolic slowdown that I do not plan to go down that road. Is it possible that CR would work for someone else? Maybe. But for me, I don’t think the number of calories I’m consuming is the issue, and I know that restricting has potential downsides that I wish to avoid.
This is a good thread, and perhaps I missed the message somewhere, but if there are any biochem folks out there who can help me understand why a body in full ketosis would still need a calorie deficit to lose fat. I get that restricting carb intake will lead to lower caloric consumption, but I thought the science behind keto, was that the metabolic changes your body goes through on keto, causes burning of fat stores for energy, which makes me wonder whether the weight loss is actually due to burning fat, vs just consuming less calories than your TDEE. It would be interesting to see a study that compares people in ketosis eating enough calories to match their TDEE vs people who are not in ketosis eating a 20% deficit to their TDEE.