Here is the study: nature. com/ articles/ ijo2017206 .pdf (had to include the spaces and remove the www as my post count doesnt allow to post links)
I see what you are saying, and indeed ive never seen any of it quantified either... but i have definitely "felt" it, like you mention... anecdotal evidence for sure, but it seems pretty clear to me this is a real thing from experience, even with the lack of clear science to back it up.
I feel like body adaptations are real weather you talk about muscle or fat. I have not ever seen anything quantified about how much myostatin goes up as we progress with muscle building, but its clear we decrease the rate we can put on muscle as we progress. Now i know these are completely different things that happen via different processes/pathways, but still... im just using it as something to compare.
I didnt know that exercise had a stronger impact than decreased caloric intake. Good to know. But i guess there isnt much we can do about it right? Just have to deal with it.
That classic michael phelps 7k calorie diet thing cames to mind. lol There is no way he can eat 7k without training nonstop and not get fat. If his metabolism was that fast on its own without training the guy would have dissappeared by now.
Also, deficit is super variable... As we put on muscle our metabolism increases so we have to be adjusting all the time.
Im doing a cut right now, and im trying this on/off week pattern for the first time. Im not going two full weeks high calorie, only one. But it does seem to be making a difference.
Completely anecdotal as you said, but a full week of higher calorie intake seems to impact my metabolism dramatically. Or at least work wonders in stop staggering fat loss.
I`ve been through 2 high cal weeks and the following 2/3 after them seem to work faster for fat loss. I have just started the 3rd high cal week yesterday. Im going more on feel than set standards... like... ill keep deficit until i think the effectiveness is decreasing than ill start a high cal week. And it seems to be working as expected.
Layne norton did a video on this if you would like to check it out for a summary of the study, instead of going through its 10 pages
Check it out... let me know what you think
youtube. com/ watch?v=6gQCqxnchR4
OK, so I don't have much time to respond, but this is all interesting and I want to haha. Good points that anecdotal evidence is not always wrong. There are studies out there at least showing that the changes you suggest from exercise do occur, and further to the point studies showing that modifying the reaction has noticeable results. This modification part is key because it shows that the theory plays out in reality somehow.
I agree with homeostasis - all the more reason NOT to adjust metabolism. In reality, our bodies are designed to go through feast and famine. If, every time we have a big meal, we adjust our metabolism upwards - then we hinder our ability to store for that famine. It makes no sense. Adjusting down at least makes some sense - we train to become better and better at holding onto calories; but this is improved efficiency and you would expect exercise to have the same impact. I.e. - someone who has never done cardio and runs a mile at the same pace, etc. will likely have a harder time and burn more calories than someone who is well trained and does the same thing all the time. Even still, I would expect the differences to be minor and compensated by other factors (for instance, the trained person can generate more intensity). We don't ever say, "Don't exercise because your metabolism will become more efficient". To the exact point, we talk about how the increased muscle mass or activity will burn more calories.
The Phelps example is proof of my point - no way he will ever "rev up" his metabolism to burn 7,000 calories without exercise. I think that's part of the reason this myth actually exists though - because people tend to under-account for work. They see him and how lean he is and say, "well, it's because he eats so much and is in such good shape that he is in good shape" and it feels good to believe that. If he stops exercising suddenly he will grow fast on those calories, or even less. This is known to be the issue with the "muscle turns to fat when you stop training" myth that bodybuilding always had for decades.
Another reason I think people believe this is that when they try to lose weight they start cranking up the exercise, and you can't do as much exercise if you aren't eating calories - or at least not as intensely. So, people on huge deficits and a lot more exercise than they are used to increase calories and suddenly their exercise becomes more intense and longer, etc. - so they are burning more calories on the other end (as you say) and still in a deficit (albeit not as great) - so they feel better, get a small boost, and become better at training. It's more about finding the optimal balance of not being so tired that you can't train because your deficit is so big vs. having a deficit that allows you to do what you're actually trying to do without depleting yourself totally.
Of course, in spite of all this, only people in REALLY good shape already will be able to dramatically impact their caloric expenditure through exercise. I can cut 1,000-1500 calories a day out of my diet pretty easily. It would take me HOURS per day to do that on a treadmill and I would be so sore after the first few days I would have to stop.
In the end, keep in mind I'm not saying I'm right or wrong - just that I'm extremely skeptical and the evidence for an "adjustable metabolism" is almost non-existent beyond anecdote. It just doesn't deserve the spot it has as "fact". I question it heavily. So, we are left at the beginning of this thread - you have a theory, you have designed an experiment, now run it and see what you think. Of course, your experiment isn't necessarily designed to scientific standards (especially if you go by "feeling") - but it's an experiment none-the-less and better than most people do.
Interesting thread, would really have liked to see a third group which had one strategic refeed (not cheat) to see how that compared.......(ie. was two weeks needed?)
I don’t quite get why creating the deficit through cardio would have a positive impact in relation to the theory suggested op. There would be a whole host of other factors to consider but my simplistic understanding was that hormonal and metabolic response would occur if you are in a deficit through food or cardio (I.e the body will still detect it has less calories than it needs to maintain homeostatis) - I do agree with creating a deficit through cardio and resistance training rather than just cutting calories by the way, but my reasoning is along the benefits to cardiovascular health and maintenance of lean mass (which in turn maintains a higher bmr).
HIT4ME - sorry bro I might be totally misreading your post but isn’t having an adjustable metabolism very logical in nature? If we accept that our bodies can elicit changes to maintain the status quo or help us survive then to me it makes sense that ‘slowing’ the metabolism at a time where the body believes food is scarce (I.e reducing the calorific requirement to maintain status quo) or increasing it to avoid excessive fat gain when excess calories are consumed........
I recall analysis where the average excess calorie consumption in the us was measured and compared to the average weight gain. According to calorie math the average weight gain should have been much higher but ‘something’ occurs to prevent that.....
Just to expand on this some more - not saying we don't adapt, but study after study shows that a person who is in better shape burns fewer calories than a person who is poor shape. Sure, excess weight increases workload and thus calorie burn - but some studies don't necessarily get explained by this alone.
And excessive fat gain, in nature, is not a real concern. We go through feast and famine, we are designed for it. Does your body stop using vitamin D because you are out in the sun too much? What happens if you stop using it and then you come across a day where you are not getting any? We store and burn, store and burn. I'm not saying things don't change in how we do that, and inefficiencies can't be improved upon - but treating it like a thermostat based only on your food intake is flawed.
And as far as your calorie math - a few things could be at play. My guess is that weight gain itself causes increased caloric expenditure and this is difficult to account for. Someone who is 300 pounds and 50% bodyfat is going to burn FAR more calories than someone who is 160 pounds and 8% bodyfat. It is hard to account for the increase in weight when calculating weight gain because it may not be linear - if I gain 5 pounds per year I won't need to eat as many calories over 10 years as if I gain 50 pounds this month and stay there over 10 years.
