Nutrition Alternate Day Fasting = Less Fat Loss Than Continuous Caloric Restriction

[watchnerd]

Intermittent fasting may impart metabolic benefits independent of energy balance by initiating fasting-mediated mechanisms. This randomized controlled trial examined 24-hour fasting with 150% energy intake on alternate days for 3 weeks in lean, healthy individuals (0:150; n = 12). Control groups involved a matched degree of energy restriction applied continuously without fasting (75% energy intake daily; 75:75; n = 12) or a matched pattern of fasting without net energy restriction (200% energy intake on alternate days; 0:200; n = 12). Primary outcomes were body composition, components of energy balance, and postprandial metabolism. Daily energy restriction (75:75) reduced body mass (-1.91 ± 0.99 kilograms) almost entirely due to fat loss (-1.75 ± 0.79 kilograms) . . . Alternate-day fasting less effectively reduces body fat mass than a matched degree of daily energy restriction and without evidence of fasting-specific effects on metabolic regulation or cardiovascular health.

A randomized controlled trial to isolate the effects of fasting and energy restriction on weight loss and metabolic health in lean adults - PubMed

Intermittent fasting may impart metabolic benefits independent of energy balance by initiating fasting-mediated mechanisms. This randomized controlled trial examined 24-hour fasting with 150% energy intake on alternate days for 3 weeks in lean, healthy individuals (0:150; <i>n</i> = 12). Control...

pubmed.ncbi.nlm.nih.gov

 

[silveraw]

Any chance someone has the full text available?

also interesting that it matches up with Dr Attila’s recent anecdotes about how IF screwed up his clients bf% and he doesn’t recommend it anymore.

 

[watchnerd]

Any chance someone has the full text available?

I don't, unfortunately.

Given the calories are normalized, I don't know if the paper speculates on mechanisms; the guys at Mind Pump were speculating that, with gaps in protein intake, the body may have been eating its own protein more, but that doesn't make a huge amount of sense to me if the alternate day fasters were consuming 150% of calories on the feeding days, and presumably, 150% of protein, too. Muscle Protein Synthesis (MPS) is a pretty complex topic, but I've never heard it's that sensitive to timing as long as the net protein levels are high enough, especially given how long it takes to digest food.

In would seem disadvantageous for feast / famine hunters if binging on protein day 1 and day 3 caused muscle loss on day 2 without more protein.

 

[silveraw]

In would seem disadvantageous for feast / famine hunters if binging on protein day 1 and day 3 caused muscle loss on day 2 without more protein

I thought it was pretty well established that eating carbs did a lot to preserve muscle mass? Which is what would make up the majority of a hunter gatherer diet.

But yeah, you seem to have a better idea of MPS than I do. I was honestly more curious as full texts have the researchers notes at the end that sometimes give good insight into the results.

 

[watchnerd]

I thought it was pretty well established that eating carbs did a lot to preserve muscle mass? Which is what would make up the majority of a hunter gatherer diet.

But yeah, you seem to have a better idea of MPS than I do. I was honestly more curious as full texts have the researchers notes at the end that sometimes give good insight into the results.

Even in the case of carbs, if the total carbs are the same at the end of the week between the alternate day fasters and the regular calorie restricters, I'd be surprised if the intake timing made such a huge difference.

Unless:

If the researchers were sloppy about timings and lean body mass testing, the whole thing could be a head fake based on glycogen differences.

My "lean body mass" according to my bio-electrical impedance scale can fluctuate easily by 1-2 lbs per day just based on how much glycogen I'm storing in my muscles, which is influenced by exercise and carb intake.

 

[ShawnM]

There's a good review of this study that I reviewed on Y-Tube the other morning. The main issues with the study is that it's a 3 week study being conducted on people within healthy BMI's or much leaner. Thomas DeLauer does a decent breakdown of the study and talks about several other, much longer studies that are conducted on over weight/obese people. DeLauer can annoy the hell out of people at times but he has solid info, after you get past the commercials for Butcher Box and whatever else he's selling.

 

[watchnerd]

There's a good review of this study that I reviewed on Y-Tube the other morning. The main issues with the study is that it's a 3 week study being conducted on people within healthy BMI's or much leaner. Thomas DeLauer does a decent breakdown of the study and talks about several other, much longer studies that are conducted on over weight/obese people. DeLauer can annoy the hell out of people at times but he has solid info, after you get past the commercials for Butcher Box and whatever else he's selling.

What's the summary?

I agree that 3 weeks is pretty short and I'm skeptical that muscle mass differences would be statistically significant over such a short time span between two groups consuming the same calories, albeit with different timings.

I believe the MATADOR study was 12 weeks.

DeLauer has also said the influence of carbs on MPS is overblown.

 

[North Coast Miller]

Carb effect on MPS is minimal, but its effect on preventing breakdown is equally well established.

If trying to extrapolate to hunter-gatherer evolution, one would think an almost continuous chowing on small amounts of carbs daily, with the occasional big bump in fat and protein. Protein should def be consumed in spikes.

 

[ShawnM]

What's the summary?

I agree that 3 weeks is pretty short and I'm skeptical that muscle mass differences would be statistically significant over such a short time span between two groups consuming the same calories, albeit with different timings.

I believe the MATADOR study was 12 weeks.

DeLauer has also said the influence of carbs on MPS is overblown.

The basic summery was that the test was too short and conducted on a group of people that wouldn't really see pronounced changes with IF. He basically states that if the study was longer and with a wider range of people BMI wise in the study that the results would be more realistic. He does briefly talk about the Matador study and how it is more relevant.

 

[watchnerd]

The basic summery was that the test was too short and conducted on a group of people that wouldn't really see pronounced changes with IF. He basically states that if the study was longer and with a wider range of people BMI wise in the study that the results would be more realistic. He does briefly talk about the Matador study and how it is more relevant.

I believe I found the video you were referring to:

 

[Don Fairbanks]

I don't, unfortunately.

Given the calories are normalized, I don't know if the paper speculates on mechanisms; the guys at Mind Pump were speculating that, with gaps in protein intake, the body may have been eating its own protein more, but that doesn't make a huge amount of sense to me if the alternate day fasters were consuming 150% of calories on the feeding days, and presumably, 150% of protein, too. Muscle Protein Synthesis (MPS) is a pretty complex topic, but I've never heard it's that sensitive to timing as long as the net protein levels are high enough, especially given how long it takes to digest food.

In would seem disadvantageous for feast / famine hunters if binging on protein day 1 and day 3 caused muscle loss on day 2 without more protein.

Yes, I've heard a 24 hr. fast, possibly longer, is muscle sparing for that reason, you cannot afford to be weak and foggy when you have to hunt successfully to survive.

 

[ShawnM]

I believe I found the video you were referring to:

Yeah, I'm pretty sure that's the one.

 

[acrein]

also interesting that it matches up with Dr Attila’s recent anecdotes about how IF screwed up his clients bf% and he doesn’t recommend it anymore.

Where does Peter Attia talk about this? I'd be very interested in reading/hearing more.

 

[pood_swinger]

the body tries to preserve muscles and prioritize using glycogen, then fatty acids when glycogen is depleted. the trigger is low insulin levels (or more low insulin/glucagon ratio). people with normal "healthy" diet will start to get some ketosis after 12 hours or so. after prolonged "fasting" ,or better known as starvation, then the proteins from muscle break down start to get used as last resort.
what can't be true is that the body starts using proteins for fuel in 24h or less. imagine hunter/gatherers (or any other mammals) getting their precious muscles to start breaking down after not eating for 24 hours
for the "cardiovascular health" they don't specify what they're talking about or how they quantified it (nor how they quantified the fat loss, but I don't have the full txt)

 

[Don Fairbanks]

Where does Peter Attia talk about this? I'd be very interested in reading/hearing more.

Starts around 32:30

 

[watchnerd]

what can't be true is that the body starts using proteins for fuel in 24h or less. imagine hunter/gatherers (or any other mammals) getting their precious muscles to start breaking down after not eating for 24 hours

Exactly.

Which is why I find it difficult to accept this idea that alternating between 150% calories / 0% calories every other day lead to muscle wasting.

 

[silveraw]

I believe I found the video you were referring to:

That is interesting. In the other study he mentions people seem to "spontaneously" (not sure if that is the proper word for it) regain LBM after losing it in the first few weeks of IF. I wonder what the mechanism is for that.

Dr Norton's breakdown of the new fasting study is pretty interesting, although he fanboys a little bit because they apparantly did an amazing job with study design. Down to standardizing the fluid and food intake participants had before DEXA scans to remove any variables from that and equalizing the groups across physical activity and fat mass.


He does postulate that the muscle loss might be connected to the body not have a way of storing amino acids very well compared to glycogen and especially fat.

 

[watchnerd]

That is interesting. In the other study he mentions people seem to "spontaneously" (not sure if that is the proper word for it) regain LBM after losing it in the first few weeks of IF. I wonder what the mechanism is for that.

Glycogen.

Happens to me all the time -- I can game a Dexa LBM reading just via glycogen.

We use it as a trick all time in weightlifting when trying to make weight while on creatine.

 

[pood_swinger]

Exactly.

Which is why I find it difficult to accept this idea that alternating between 150% calories / 0% calories every other day lead to muscle wasting.

I was listening the podcast Don Fairbanks posted and he used as an example a person that gained body fat from 18% to 30% and lost muscle mass doing some type of fasting. The person wasn't doing resistance training, only some walking and yoga.
right away I would have questioned the guy about his diet, you can time restrict your meals all you want but if you get papa john's for dinner that would do the trick to make you gain body fat.
he's also talking about 7 to 10 days of fasting he used to do, starving for 10 days would also explain the loss of muscle mass.
just can't see people losing muscle mass by doing 16/8 or even periodic 24-48h fasting if they do some type of resistance training and eat healthy when they actually eat

 

[silveraw]

Glycogen.

Happens to me all the time -- I can game a Dexa LBM reading just via glycogen.

We use it as a trick all time in weightlifting when trying to make weight while on creatine.

Wouldn't standardizing food and fluid intake before the DEXA scan reduce the impact of that? Although I suppose that would only apply to the shorter study where the LBM didn't rebound.