I don’t have any interest in starting a CICO vs hormonal theory of obesity debate. I think both have valid points. I’m just looking for journal articles not opinions,( in other words, “show me the science!”. ) I’m doing some research into extended fasting and resting metabolic rate, and I just want to know if there are journal articles that either show:
A LCHF diet prevents the metabolic rate from decreasing under calorie restriction
A LCHF diet is capable of burning fat in the absence of calorie restriction
Does fasting count as keto? I guess it does because you’re only eating fat! I should have been more specific and excluded fasting, which I think is a different animal altogether from continuous calorie restriction.
In any case, Dr. Fung is only partly right. It’s true that the first time you ever do a 4 day fast your metabolism remains constant or increases slightly due to the upregulation of norepinephrine and epinephrine. He is absolutely wrong to extrapolate that to the second fast, much less the 10th. The metabolism adapts very quickly to extended fasting if you do it on a continual basis.
My friend primal.peanut over at the IDM clinic forum tests his RMR daily with an indirect calorimeter. He’s a bit of a serial faster and favors 2:5. Suffice to say his charts do not even remotely resemble the one from Zauner et al., that Dr. Fung put in his book and mentions in the lecture. His RMR drops by as much as 400kcal in the first day of an extended fast alone!!!
Good comment, Nick. I’d say this perhaps argues for mixing it up - not settling into a constant rotation of 2:5 or the like…?
I’ve never done anything really regularly - but a few times have eaten really low-calorie, like a piece of cheese and some sardines - say 400 or 500 calories. Then I’ll really be hot during the evening and night, sweaty pillow and feeling energetic enough that I really notice it. It doesn’t happen every time, but enough that I have to think it’s somewhat of a “thing.” No explanation for it.
My apologies Don. I for sure posted that video thinking your question was in the context of fasting… but after reading the title again, I see I jumped to a false conclusion.
My experience with EF is a bit limited. I did a few two day and one three day fast just so I could check it off my bucket list and to see how it affected me. I won’t say that JF is wrong or right on this about the affect on metabolism over continual EF, but I do know he’s helped a lot of people with his advice.
That’s interesting and my first impulse was to wonder if your friend’s patterns of restriction might be the cause of this. JF is an advocate of feasting and fasting and specifically, breaking up patterns to avoid lowering BMR.
This study talks about RMR (Resting Metabolic Rate) compared over 4 months of “low calorie ketogenic diet”.
The conclusion:
The rapid and sustained weight and FM loss induced by VLCK-diet in obese subjects did not induce the expected reduction in RMR, probably due to the preservation of lean mass.
I’m one of them that’s for sure. I love Dr. Jason Fung. I buy copies of The Obesity Code and pretty much hand them out like candy! That book changed my life. So did his “Complete Guide to Fasting”.
His fasting pattern most definitely caused this. He never restricts calories. He’s either eating 3000kcal-3500kcal per day, or he’s fasting. Without getting too far into the weeds, it’s possible to dramatically increase your metabolism through a process called “metabolic ramping”. All it takes is basically cycling hypocaloric feasts followed immediately by fasts on a serial basis for a period of time. Primal.Peanut has a predicted RMR of 1700kcal/day given his weight/height/age, but he increased it to around 2400kcal per day through MR. That’s well into the 99th percentile. Weight loss happens very quickly when your metabolism is 40% faster than average. We’re working on a project to better understand the underlying cause of the metabolic adaptation of Fasting RMR Decline, and flatten the slope. We’ve made good progress so far by changing the feast/fast patterns.
I’m trying to find variables we can play with to preserve RMR, and the ketogenic diet is an obvious choice. I’m trying to find studies about keto that suggest that it can inhibit the reduction in RMR that otherwise inevitably follow continuous caloric restriction to understand what specifically could allow this to happen.
Yup. I think mixing it up is a good idea. Or in the very least putting more space between extended water fasts. I’ve been doing 3 Feast (3500kcal/day):3 Water Fast continuously for 7 weeks. When my indirect calorimeter gets in two weeks from now, we’ll get a chance to see what effect an even ratio of feasting days to fasting days has. I expect it will be better than 2:5, but who knows.
I think the optimal approach is to use metabolic ramping to increase RMR 30%-40% over the course of a month, and then space extended fasts at least far enough apart that the slope of the fasting RMR decline is close to 0. I’ve no idea what that spacing is, but we’re going to find out.
The sensible thing to do though is just to do an extended fast for couple days once or twice a month and call it a day. Well, that’s not entirely true, the sensible thing to do is probably just forget about fasting altogether and KCKO.
There was a study done on low carb and rmr which concluded that there was no effect while they were limited to like 800 calorie lchf diet. The doctor i heard this from was David Ludwig. I cant remember which video it was though.
Cool - love this stuff. And this is a the good type of Quixotic quest to be on.
Nick, on your friend’s lessened RMR while fasting - are the non-fasting readings taken in the morning, before eating, or otherwise when digestion is not going on?
I’ve always heard that roughly 10% of our energy goes toward digestion. This may be one of those things that gets a life of its own, even though false, but obviously some energy is used. With protein, it’s as high as 35% of the energy contained being consumed in the processing of it. All other things being equal, we should have a lowered RMR when not eating.
@OldDoug makes 17th Spanish literary reference. +10 points for Gryffindor! Let’s hope I’m not tilting at windmills.
Absolutely true. The strange thing is that for people who do an extended fast for the first time, even in the absence of the thermic effect of food, metabolism slightly increases for the first few days. In fact, Owens et al. found that RMR only decreased 8% over the course of 18 days, and part of that could be explained by the loss of body mass. On the 20th fast however this is no longer necessarily true. Whatever the mechanism is that maintains RMR during a water fast loses efficacy.
With so little data, and so many variables, it’s hard to figure out what’s happening. We just got back data from another 5 day fast. I talked PP into lifting for the first time this week to see what it did (Body by Science of course ) . His RMR reached it’s nadir on day 1 dropping 400kcal in 24hrs from 2400 to 2000kcal/day. The next day PP lifted weights, and his RMR climbed 50kcal/day for the next 4 days all the way back to 2200kcal/day on the 5th day (120th hr) of his fast. We’re baffled by that but want to see if we can replicate it next week. My theory is that the workout, which emphasizes the eccentric portion of the lift to maximize muscle damage, triggered a big 'ol autophagy party given that it was in the middle of a water fast. If so, that would be pretty amazing.
Join the project! You ought to get yourself an indirect calorimeter @OldDoug. You can get one for $250-$350, that’s FDA cleared for medical use and accurate to +/-2%. It just needs to be recertified at the factory. PM me if you’re interested.
Here is the Owen et al. 21 day water fasting study. Check out the stability of the RMR over the full 3 weeks. It’s amazing. But again, these fellas were fasting for the first time.
I wouldn’t get too excited about that study, as far as it showing an absence of metabolic slowdown while on VLCHF diets that restrict calories. Four months is far too short of a time, not only for elimination of derangement, but for significant fat loss in the obese as well.
I pretty much fit the parameters for that study, and it took about two years for detrimental metabolic effects to occur.
They would naturally occur sooner for those less deranged or obese, but would also be subject to degree of activity. For example, effects could occur much more rapidly for those rigorously training.
Interesting! Is it that the detrimental metabolic effects appeared 2 years after the weight loss was complete (i.e. 2 years into maintenance), or that the detrimental metabolic effects didn’t come into play until 2 years into the ongoing weight loss?
Again, not exactly what you were originally asking, but here’s a study that shows that at maintenance levels of caloric intake people on low-carb diets burn more calories than people on high carb diets. The “low carb” was 20% of calories, so not exactly the very low carb levels most of us think of as “keto.” However, even if this increased RMR held true under caloric restriction to lose weight, I don’t think it suggests that it might also be protective to that RMR starting point over time.
These participants were then randomized to follow high-, moderate- or low-carbohydrate diets for an additional 20 weeks – with carbs comprising 60, 40 and 20 percent of total calories, respectively. Carbs provided to all three groups were of high quality, conforming to guidelines for minimizing sugar and using whole rather than highly processed grains.
In all three groups, total calorie intake was adjusted to maintain weight loss, so participants’ weight did not change notably. During this phase, the goal was to compare energy expenditure – how the different groups burned calories at the same weight. Energy expenditure was measured by a gold-standard method using doubly labeled water.
Over the 20 weeks, total energy expenditure was significantly greater on the low-carbohydrate diet versus the high-carbohydrate diet. At the same average body weight, participants who consumed the low-carb diet burned about 250 kilocalories a day more than those on the high-carb diet.
) I’m doing some research into extended fasting and resting metabolic rate, and I just want to know if there are journal articles that either show:
I should have been more specific and excluded fasting, which I think is a different animal altogether from continuous calorie restriction.
Cool - love this stuff. And this is a the good type of Quixotic quest to be on. 