Caloric restriction's impact on muscle mass, strength, and the immune system | Matt Kaeberlein

[@danieltscharnuter4794]

I would argue that when I aim to reduce calories the nutrition is not getting worse, it rather improves because I have to pay more attention to what I eat compared to not caring about calories.

[@bwilds]

Muscle Mass and Strength: - Mixed results: Some studies suggest CR may preserve muscle mass and function, while others show a decrease. - Normalization to body weight: CR often leads to weight loss, and muscle mass and strength are often normalized to body weight in studies. This makes it difficult to directly compare CR groups to control groups. - Importance of maintaining lean body mass: Losing muscle mass along with fat is generally considered undesirable, as it can lead to functional decline and frailty. Immune System: - Compromised immune function: Some studies suggest CR may compromise the immune system, particularly in response to certain challenges like sepsis. - Importance of optimal nutrition: The negative effects on the immune system may be more pronounced when CR is not combined with adequate nutrient intake. - Need for further research: More research is needed to fully understand the effects of CR on the human immune system, especially in different age groups and health conditions. Other Considerations: - Individual variability: The effects of CR can vary greatly among individuals due to genetic and lifestyle factors. - Long-term effects: The long-term effects of CR on human health are still unknown, and more research is needed to determine if the potential benefits outweigh the risks. - Practical challenges: Adhering to a strict CR diet for extended periods can be difficult for most people.

[@DLL-y4p]

Thank you!

[@johnwilhelm]

I can say for over ten years of CR I had a difficult time maintaining muscle mass. I felt great, looked great but in the back of my head started asking what about frailty. I just turned 50 last year and decided to give up on CR. The big question, what is the balance to get the health benefits of CR but also maintain decent muscle mass.

[@KasKade7]

I mean the classic bulking and cutting phases work great for muscle mass. The way I do it is bulking in the winter (3-4)months and having a slight surplus of calories. Maybe 10-15%. The rest of the year I also try to maintain around 10% CR. I got 6-pack year round and plenty of muscle mass. Interestingly, I don't lose that muscle mass when going CR. This is where I think a high protein diet helps too. Obviously, you're never going to look like a BB'r with this CR lifestyle. But longevity is more interesting.

[@kevinlilly619]

This seems to be a part of a longer interview. How are you defining CR. Does it mean a caloric deficiency? Or something else?

[@jaymckoskey25]

Isn't ideal body composition the real goal for energy balance manipulation? If you're there why would you want continued energy deficit, ie: to lose more weight? Ideal body fat percent seems like a key question that never gets asked or answered. I've concluded that for a 60 year old male it's around 15% but I know of nothing conclusive showing this.

[@Hugues.L]

60 yo here, looks like i'm at 15% but it's all around my belly LOL, does it count ?

[@jaymckoskey25]

@@Hugues.L The location of subcutaneous fat isn't critical, as far as I can tell, but visceral fat is a big problem and that is located in the belly. If you've gotten a DEXA scan then it should tell you how much visceral fat you have. According to my DEXA print out 0.5 - 1 lb of visceral fat is fair and under 0.5 lb of visceral fat is excellent. If you haven't gotten a DEXA scan then you may find that your body fat % isn't necessarily what you expected. Mine was a rude awakening after having gotten body fat percentage estimates from a caliper and bio impedance.

[@Rocket33r]

How far off was caliper to the DEXA?​@@jaymckoskey25

[@Rocket33r]

My thing with CR though is, if you CR long enough, is it still CR? What I mean is, if you eat a 20% deficit indefinitely, you won't lose weight at some point, your weight will plateau. So presumably this means your body has achieved some efficiency based on the amount of food it is getting. Edit: I guess you would have to continue to cut more and more calories. At which point you would be undernourished. So presumably that's what you are talking about? I'm just thinking about this, because Bryan Johnson says he eats CR, but always 2250kcal and he is metabolically efficient, so he isn't really in a deficit imo.

[@lucashemenway7026]

I think for this you'd also have to consider other variables. If one is always in CR, does that person's body reach an equilibrium with what fuel it's getting before it gets too sick because the immune system is non existent and malnourished?

[@kuro2797]

I think the difference is that once you reach the bottom of reserves, the body is no longer trying to 'take' energy from said reserves, and instead lowers the activity of the metabolism (hence why you get a lower core temp). In other words, you're still at a caloric deficit. It's just your body's no longer trying to compensate via reserves and instead compensates via reducing consumption.

[@Rocket33r]

@@lucashemenway7026 yeah, I think it also depends on how much CR and how good the diet is. If you are above RDA on all macro and micronutrients, but below RDA on calories, I wouldn't expect most people to get sick from that. I think adult humans are too robust for that. Edit: But I think the guest excludes this case as an exception.

[@Rocket33r]

@@kuro2797 I see what you mean, that makes sense.

[@SladkaPritomnost]

Bryan Johnson is in caloric deficit considering his amount of physical activity

[@maciejguzek3442]

Can you try to summarize some points about the usefulness of periodical fasting for active people? Like 'general guidelines', for example 'it seems benefits of a 24h fast are so noticeable that healthy people should tend do it once a month'? (Just an example, I have no idea what these guidelines would look like, but the point is, I heard a lot of such good things about fasting, but still I have no idea if it makes sense to do them if Im healthy and feel great)

[@jeffr9854]

Not sure why but anytime I go into a calorie deficit I rarely if ever get anymore than mildly sick. When in a surplus it seems I catch everything.

[@itsxtray]

Interestingly, I haven't been sick in years and never even caught COVID, but I've lost 45 pounds since October and just got sick for the first time in over a decade.

[@Mk7Albert]

Maybe it has to do with how much processed food you’re eating/carb intake/over all sugar intake

[@SladkaPritomnost]

I'm very lean BMI 20, I get more easely sick on CR.

[@tywonellington]

Just a thought, but by sick do you mean getting colds? Cold symptoms are just immune response, so if you have lower immune response you may be getting colds and not even knowing it. A symptomatic colds are common.

[@jeffr9854]

@ yes that’s what I meant.

[@ethanbound3657]

Attia LOVES the acronyms 😂

[@SuperDodoe]

BS is his favorite

[@zack_120]

Finally the cons of CR are also exposed instead of the overwhelmingly biased way speaking of its pros only.

[@mec210G2]

Matt sounds reassuringly like the scientist from Half-Life 1

[@BDBMX]

Now you've said it I can't unhear it, that is uncanny

[@oneworldfamily]

That was an odd place to end it on 🤔

[@grantferrigan3837]

How much do we really need? I'm 56, sometimes I eat less, sometimes more. I feel 30. Find your balance.

[@reynemanzano]

Be careful using this clip to inform you exclusively. Dr. Attia points to additional informative data on protein intake with regard to age. Apparently, people need progressively more protein as they age in order to maintain adequate muscle function. It’s a bit more complex than my paraphrase, so I’d find the content yourself

[@johnnyg2501]

Dude if i want to CR you cant stop me

[@SuperDodoe]

Caloric restriction is really energy balance meaning youre maintaining body weight . Add in resistance training to bias body composition towards muscle rather than fat. So much talking only to confuse

[@johnnyg2501]

Ah yes cr

[@ageresequituresse]

Never trust anyone who looks like Matt Kaeberlein.

[@maciejguzek3442]

That's cruel 😅 Yeah somehow he doesn't look like an example of health, but we don't know what are his genetics or illnesses/struggles, it is entirely possible that he's a genius (I didn't listen to this conversation though)

[@kuro2797]

It's funny. I thought he looks like Mark Pellegrino (a guy who plays the devil in a show called Supernatural).

[@jaleneellis-weigand2310]

Seriously? This comment right here is the problem with our society.

[@maciejguzek3442]

@@jaleneellis-weigand2310 No, his comment is valid. If someone claims to be an expert about ageing and looks old for his age, or talks about muscle mass and athleticism while being un-athletic, it may undermine his credibility.

[@jaleneellis-weigand2310]

@ he’s 53, and looks 33. And having strong muscle mass it toned and not bulky. He looks very healthy.