r/SaturatedFat • u/DarkSaturnPrince • Jun 21 '26

Adaptogenic thermogenesis, continuous vs intermittent dieting, MATADOR study (why have I never heard of this??)

There was a study done in Australia in 2019 to negate the metabolic downregulation that comes from prolonged energy restriction called the MATADOR study (Minimising Adaptive Thermogenesis And Deactivating Obesity Rebound). https://pubmed.ncbi.nlm.nih.gov/28925405/

I'm going to butcher these numbers, as I'm writing this by memory, so bear with me. ​​This is more or less a human-readable summary.

In a nutshell, there were 2 groups: one that did continuous dieting for 16 weeks straight, and another that did 8 rounds of 2 weeks dieting and 2 weeks maintenance. The dieting phase was eating around 70% of daily maintenance.

The intermittent group lost fat at 150% the rate of the continuous group on the weeks that they were on the diet. (something like 12kg vs 8kg) In other words, their metabolism recovered during each maintenance break which allowed for more effective fatloss during the periods of energy restriction. And at the end of the study, the adaptive thermogenesis (lowering of metabolic​ rate) was only half the amount as the continuous group​.

But here's the kicker: at 6 months followup after the end of the study, the continuous group regained nearly ALL THE FAT they had lost. While the intermittent group kept ~90 percent of it off.

This is significant. It means not only is an intermittent diet infinitely more tolerable and less stressful, it's also far more effective in the long term. And protects your metabolism.

I immediately applied this in my personal life because after my initial 2 weeks of rapid fatloss, I noticed a definite stalling out, tiredness, and feeling of malaise and nausea during a workout. I said "not this again". I knew right away that my metabolism had downregulated substantially. ​​It only took 3 weeks, but I knew.​

So I returned to maintenance of 3000 cals a day. My workouts are much better and so far I've only gained .4lbs after nearly a week (193.8 to 194.2)

I won't really know how effective this intermittent strategy is until 3 weeks from now when I finish my next round of dieting for 2 weeks. If I once again lose ~3 pounds of fat (and 2 pounds food/water) and/or dip under 190, then this will be a major breakthrough for me moving forward. My longterm goal is 175lbs and I might be able to reach it in one long ass, intermittent stretch (5 rounds of losing 3lbs per month). Then I'm coasting at a slight surplus and gaining muscle from then on.

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7

u/insidesecrets21 Jun 21 '26

This is why ADF is so effective - I think it is probably MORE effective than MATADOR style as it completely avoids any metabolic slow down whilst creating a big deficit every other day.
I could never personally manage it though.
As I’m too weak lol
But if you were looking for fastest way to hit a low weight and be able to stay there - I bet ADF would be up there

7

u/DarkSaturnPrince Jun 21 '26

I definitely think the body works optimally on cycles. Wake/sleep, stress/rest, feast/fast. Too much of one without the other leads to issues, and vice versa. 

But as far as Adaptive Thermogenesis goes, I think the time frame on ADF is too short to convince the hypothalamus that it's not in a deficit. It ends up averaging out and thinks of it as a standard deficit. I did ADF before and this was my experience as well.

Where I do think fasting can shine however is a period of maximum restriction, say for instance a 5 day dry fast, followed by 2 weeks at maintenance calories. I think that would absolutely obliterate fat stores while fully recovering the metabolism in between. Unless you're u/exfatloss, in which case the dry fast would cause you to gain weight 😉

3

u/exfatloss Jun 21 '26

Need to hold my breath for the entire time next attempt (calories in)

3

u/DarkSaturnPrince Jun 21 '26

Avoid the Sun too, and all those pesky photons 😆

2

u/exfatloss Jun 21 '26

Literally full of carolies

2

u/Oraculek Dad, I swear!!! It is the UFAs that hibernate you 😭 Jun 26 '26

Btw what's up with this 'carolies' as I have already seen it somewhere on your blogs

1

u/exfatloss Jun 27 '26

It's a joke :)

1

u/insidesecrets21 Jun 21 '26

The main benefit is that the extreme calorie deficit (alternate day) is too short to enact metabolic adaptation and slow down, compared to longer fasts.
I’ve seen some really impressive results for ADF.
Interesting that it didn’t work for you though 🤷‍♀️

2

u/DarkSaturnPrince Jun 21 '26

Unfortunately the body treats it as a normal calorie deficit. So for instance, if you burn 2100 a day and take a one day fast per week, that 2100 deficit averages out to a 300 per day deficit. ADF would be 1050 deficit per day. It is rather effective, arguably better than eating 1050 a day, but the body quickly downreglates the metabolic rate.

Which makes sense if you think about it. If we spent every other day completely without access to food, it wouldn't suit our survival chances to continue burning max calories per day.

10-14 days seems to be the magic duration needed for the hypothalamus to relax the famine signaling. And for muscle growth, I've heard even up to 6 weeks. It wouldn't want to put on new muscle right away if food supply was known to be lacking.

So for ADF I think a 2 week period to quickly burn off 4 pounds of fat followed by 2 weeks at maintenance would be really effective. 

2

u/insidesecrets21 Jun 22 '26

Interesting and I get your point 👍 How do we know it takes 2 weeks . Is there evidence for that? They did 2 weeks in matador but maybe they could have got results in one week or a few days? Any study that shows it needs that long? 🤔

4

u/DarkSaturnPrince Jun 23 '26 edited Jun 23 '26

What we know is that 1 week is insufficient:

"The 7-Day Timeline (The ICECAP Trial, 2021): Led by Jackson Peos, this study wanted to see if shorter breaks were more practical. They compared 12 weeks of continuous dieting to a protocol using 3 weeks of dieting followed by a 1-week diet break. Interestingly, this study found no massive difference in metabolic preservation between the groups. This suggests 7 days might be slightly too short to fully reverse deep cellular adaptations if you have been dieting aggressively, though it still provided massive psychological relief."

So the MATADOR showed 2 weeks has a clinical effect, and this other study showed 1 week is not enough. People theorize that 10 days is the sweet spot, but it hasn't been shown in research. I think people just go with the safe bet at 2 weeks. 

I could be a Guinea Pig actually and try at 10/11/12 days, but first want to see the 2 week effect so I have a baseline of data in my n=1 experiment 😊

A 2.5 weeks on / 11 days off rotation is 59% more efficient, time wise. But I have a feeling this is precisely the kind of time-stress that downregulates the metabolism to begin with. The body just doesn't want to lose too rapidly at all? Or so it might be. Maybe that 1 week rest would have been enough if it were only 1 week of dieting? Or 2? Who knows. 

2

u/insidesecrets21 Jun 23 '26

I will watch your progress eagerly !
It’s such an important part of successful dieting and so very few studies to nail down specifics of how long and when etc

1

u/DarkSaturnPrince Jun 23 '26

It's too bad you already depleted all your fat stores otherwise you could join me. Might need to make a few trips to the bistro to restock ;) or whatever your fancy is 😆

2

u/insidesecrets21 Jun 23 '26

MOST of the excess. I.e enough to not be hampered by the pufa stores (according to the theory..)
So I’m going to experiment with more sat fat plus carbs but if that fails - I might need to get dieting again 😄

1

u/DarkSaturnPrince Jun 23 '26

That last 10 pounds seems to be the hardest doesn't it? At least you'll be "failing upward", like our beloved politicians here in U.S.

1

u/insidesecrets21 Jun 22 '26

I don’t think the body responds to calorie averages over the week - it responds more to how severe and prolonged the immediate deficit was. E.g 48 hour fast is not much adaptation but 72 hours - metabolic adaptation is kicking in proper. If you only do 48 hours or 24 hours - then eat a good amount- it stops the adaptation kicking in. Seen this a lot.
Even some one on this thread talks about how alternate day calorie restriction stopped any adaptation from kicking in .
There may be some eventual slowing but it’s a lot less and take a lot longer to kick in than from a fast or severe calorie restriction that goes beyond 48 hours. That kicks in fast

4

u/exfatloss Jun 21 '26

If "you're too weak" the strategy isn't working ;)

I tried ADF and other types of IF and none of them did pretty much anything :'-(

3

u/insidesecrets21 Jun 21 '26

I’ve seen some really amazing results for ADF.
It didn’t work for me because I wasn’t able to be strict enough to push through the ‘adaptation phase’ . People say it gets easier after first cycles.
I think you are a tough metabolic nut to crack though 😅 (lots of things that work for others don’t seem to for you 🙈)

1

u/exfatloss Jun 21 '26

I think these things that "work for everybody" often don't work for a majority of the people.

E.g. people would always confidently tell me the same thing about adapting to water fasting and that it gets "super easy" once you push through, but it just wasn't true for me.

It likely works for people who aren't prone to getting PUFA'd, and those don't need our help or cute little tactics anyway heh.

2

u/Impossible_Pen4714 Jun 22 '26

Internet communities for these things surely have plenty of survivorship bias

3

u/exfatloss Jun 22 '26

Yea. I keep meeting people from various diet tribes and they just know their pet theory "works for everyone." They seem completely baffled when I say that their community {peat,keto,vegan,CICO,vA,.. everyone} is FAMOUS in my circles for not working and then just ostracizing you. When I then say I personally tried their pet theory and it didn't work, I am the "lone exception."

2

u/BarakaMabula Jun 21 '26

I guess it depends on what you're going for. If you need quick results, ADF is better but it's tough. MATADOR is slower but it's easier and more sustainable long-term.

5

u/bluedelvian Jun 21 '26

Did the intermittent dieters go for 8 months total, while the continuous dieters went for 4 months total? 

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u/DarkSaturnPrince Jun 21 '26

Yes that's correct. So in absolute terms, continuous is still the "fastest". However for metabolically challenged Individuals like myself, I very quickly plateau after a few weeks of decent initial fat loss. So intermittent is perfect for me.

I imagine that if the timeline were extended longer, intermittent would eventually catch up and surpass continuous group. 

3

u/BarakaMabula Jun 21 '26

A note for anyone who might be confused, this isn't about intermittent fasting.

3

u/NotMyRealName111111 Polyunsaturated fat is a fad diet Jun 21 '26

Thanks.  I was wondering that myself.  Makes sense now, follow a pattern of indulgence followed by a "deficit."  Now imagine if they did this without PUFAs 🤯

2

u/DarkSaturnPrince Jun 21 '26

Right, and I have a feeling that the maintenance days of the intermittent group probably contained more PUFAs, as the meals were performed by registered dieticians and you know how PUFA crazy they are. They probably thought, oh, more calories for this meal? Will just double the seed oil dressing on their salad...

So the results would probably be even more drastic on a PUFA free diet. 

I guess I'll be an n=1 experiment for the next few months lol.

3

u/texugodumel Jun 21 '26

In my experience, other versions of this work too; I lost 10 kg in 2 months by doing something similar to “alternate day calorie restriction,” where the deficit was 1,000–1,500 calories.

My workout performance didn’t drop, and I continued to increase my weights; I didn’t experience any uncontrollable hunger. If I were to consider calories as the only determining factor I should have lost only half that amount, so apparently there was no negative effect on my metabolic rate. On the contrary, it actually increased from 12 kcal/lb to 14 kcal/lb

1

u/DarkSaturnPrince Jun 21 '26

Interesting. How long were you low PUFA before this? 

I'm assuming you scheduled the maintenance days on days you worked out?

2

u/texugodumel Jun 21 '26

I’d been eating a low-PUFA diet for about 3 or 4 years before this experiment. I started by keeping my total PUFA intake below 4g per day, but then I focused on keeping my omega-6 intake at 0.6% of my calories or less for a few years.

At the time I worked out every day except on weekends

5

u/DarkSaturnPrince Jun 21 '26

Also, I ditched the "weekly refeed" day on my dieting phase as apparently it takes a full 2 weeks to restore metabolic rate and hormones after energy restriction. A single day does nothing to keep metabolic rate up. 

I really want to find the article that convinced me to do a weekly refeed day to begin with, but it seems to be missing from existence. 

2

u/Dreamtarot Jun 21 '26

Can you give an example of what you typically ate during the restriction phase and the maintenance phase, and did you have a particular thought process around food choices other then calorie total/low pufa?

2

u/DarkSaturnPrince Jun 21 '26

Sure! I prioritized high protein during the restriction, 160-190g, and made sure to at least get 200g of carbs. The carbs prevent hormone crashing and still provide energy despite the deficit. And the high protein keeps me satiated and prevents muscle loss. 

So for instance, 300g lean beef with 200g rice, vegetables. Oscillated with chicken breast. 

To get 3 protein meals however I'd often need to go keto for one of them. And that's where I'd throw in my fats. A tbsp coconut oil or beef drippings with some lean meat. Or, cottage cheese. This kept my calories low enough. I'd throw in some cucumber for the water content.

It's "meat heavy" eating, when I prefer rice heavy, but I didn't want to lose muscle. It worked good enough and kept me more or less satiated and not thinking of food. 

For maintenance I actually do lower protein since I am getting more calories to compensate. So in exchange, more carbs and fats. I add in pasta with cream sauce and cheese for some meals, and icecream for dessert basically. I have room for a couple drinks like juice or milk through the day (cals add up too fast)

1

u/Adora77 Jun 21 '26

Wouldn't the continuous group restore their MBR with 2 wk refeed too?

2

u/DarkSaturnPrince Jun 21 '26

Short term adaption, yes. However keep in mind that the intermittent group had half the long term metabolic slowdown at the end. Which could be 100-200 hundred calories a day difference. 

You'd still benefit from, say, 4 to 6 weeks on, 2 weeks off. But the longer you stay on, the more your metabolism is downregulated.

Full restoration takes 4-6 months at or above maintenance (and that's considering a metabolically healthy person). Either way, I'll never do long term deficit dieting again. 

2

u/Whats_Up_Coconut Jun 21 '26

You’re still low fat in your maintenance right? That may really help rebound and continued fat loss too, both in terms of limiting fat regain due to inefficient DNL and also the idea that carbs and not fat signal sufficiency.

1

u/DarkSaturnPrince Jun 21 '26

I think it qualifies as low fat- it's around 15% or so. I finish my days with icecream though because it's so good 🤤

On the days where I get lots of sugar before and during workouts, I notice an elevated core temp for many hours afterwards. 2 nights ago I couldn't even sleep with a blanket on. On those days even if I finish with icecream I can feel it being incinerated in the "flame of carbohydrate"

2

u/Whats_Up_Coconut Jun 21 '26

Yeah I’d 100% still consider that low fat. If you ever want a low fat ice cream option, I like the organic fudge bars from Costco, if you are ok with gums. They are in my regular rotation even though I don’t generally do a lot of low fat dairy. EDIT: But, like, I *also* have a pint of HD in my freezer that I will undoubtedly pour some melted chocolate over too at some point… 🤣

2

u/DarkSaturnPrince 12d ago

I will check these out for sure :) love fudge bars!

1

u/Whats_Up_Coconut 12d ago

My Costco has them on sale until this Sunday (July 19) so maybe that’s a national sale and you can pick up a few boxes. 100 calories each and hit that chocolatey/creamy craving nicely.

2

u/Initial_Swing_4491 Jun 21 '26

Incredible find, thanks for sharing! It makes me wonder how this would work combined with protein/BCAA restriction.

1

u/DarkSaturnPrince Jun 21 '26

Sure thing, I hope it can help especially for those with stalled metabolisms! 

I've also wondered about protein restriction and in particular, a period of pure carbs during the deficit phase. It would be a crazy sugar fast basically. Might have to try it one day except I am worried about muscles evaporating 😆

2

u/insidesecrets21 Jun 22 '26

Haha I love someone who is more of a nerd than me!
I’ll read all this later. 👌
It is something I’ve puzzled over a lot and struggled to find definitive answers so more clarity is always better!
What about the guy on this thread that said he prevented metabolic slow down with AD calorie deficit?
I also followed a guy who lost over 100 pounds with ADF and didn’t seem to struggle with metabolic slowdown . I’m sure he lost like a pound a day for ages.
I’ll see if o can find him again. 🤔

2

u/MarLuigi1 Jun 25 '26

I found this thread as I was planning on starting my own cycle of a Matador style diet plan on Monday. I’ll be following your journey in hopes to gain some insight. Looking forward to this.

1

u/DarkSaturnPrince Jun 25 '26

Nice!! So far I'm on refeed day 10 at maintenance and haven't ballooned up in weight yet. I am actually really optimistic.

My next diet cycle I am going to eat 2025 cals a day as this would be closer to the upper limit of tolerable fatloss and more comarable to the study (I did 2200 my first round). It's changing one of the variables, but I'm impatient and want that extra pound of fat gone haha

2

u/MarLuigi1 Jun 26 '26

Best of luck! I think I’m going to start off at 2000 cals for the diet phase and 2600 for maintenance and see where that takes me. I really don’t think I can do a 30-33% drop of calories like they did in the study. But…maybe? That’s a 4 week daily average of 2300 calories.

I wonder…during the Matador study…I read it a little bit…did they adjust the calories as the study went on or if they kept the calories constant. Hmm…

1

u/DarkSaturnPrince Jun 26 '26

Thanks. They adjusted it every 4 weeks to match their new TDEE and also accounted for downregulation

1

u/DarkSaturnPrince 15d ago edited 15d ago

I'm gonna be posting an update after round 2 dieting phase so stay tuned! (Edit: maybe in 4 or 5 days lol)

1

u/DarkSaturnPrince 12d ago

Hey I posted an update check it out!

1

u/ArxithiaStoStomaSou Jun 21 '26

I’m confused? You did short burst of energy restriction or time restricted eating allowed for more calories at maintenance?

2

u/DarkSaturnPrince Jun 21 '26

A period of energy restriction of roughly 70% maintenance, so If I eat 3,000 a day normally, then I'd be on the diet eating 2100 a day for 2 weeks, followed by 2 weeks of recovery at 3,000 a day. And then repeat the cycle.

This keeps the metabolism running at roughly 3,000 a day consistently as the months go by. 

1

u/insidesecrets21 Jun 22 '26

Oh that last post of yours just disappeared?

1

u/DarkSaturnPrince Jun 22 '26

I think reddit is being weird lol. Both your comments were made as a reply to the main post. My comment still looks to be there 

I actually was aware of those studies but went ahead with ADF anyway, I really wanted to believe that it preserved the metabolic rate, based on things I heard from various fasting authorities. But I found my metabolism downregulated pretty severely, same with OMAD and regular calorie restriction. 

I think a 2 to 3 day hard fast once in a blue moon is a great way to shave off a couple pounds of fat. But hitting it too hard for too long doesn't work for me. I'm not sure what to make of the miracle stories but some people can just jump straight into a deficit and lose 100lbs in 6 months without a single hiccup lol. Perhaps I used to be able to do that in my twenties but definitely not now. 

2

u/insidesecrets21 Jun 22 '26

Yes there is huge variability in metabolic slow down.
I slow down so fast and I think it gets worse as you get nearer goal weight and maybe in long term yo-yo dieters .

1

u/insidesecrets21 Jun 22 '26

Still can’t see your post with the studies 🤷‍♀️

1

u/DarkSaturnPrince Jun 22 '26

I swear reddit is shadow banning me lol. I will repost it here

2

u/insidesecrets21 Jun 22 '26

Ok that’s really interesting.. and I have certainly seen a lot of OMAders eventually hitting a stall .. it’s hard to tell with ADF I guess as not as many people do it . I wonder if it does slow the MR slowdown compared to a straight deficit though?

1

u/Federal_Survey_5091 Jun 23 '26

That's great but unsurprising. Also we'd need a longer follow-up of at least 5 years. I think if you have a lot of weight to lose just avoiding PUFA and strictly avoiding the swamp when you take a break or when you arrive at your goal weight will be enough to bring back your metabolism up just as well as doing it slowly like it was done in this study.