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longevity86

long-term CR vs. continual weight loss?

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I assume this has been covered on the forums, but I haven't been able to find it. (And, I confess to not having read any of the CR books....)

 

Granting that metabolism & nutrition are very complicated, it still seems like:

- at steady state, adequate calories = no weight gain or loss

 

and therefore:

- calorie restriction = weight loss

 

Let's ignore the question of whether a little extra weight is protective when one is 'old', and focus on age 25-50 or some such. When a long-term CR practitioner doesn't want to lose more weight, must CR (and the potential benefits thereof) stop?

 

If not, what am I missing?

 

Thanks!

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I'm not an expert on this, but I think most speak of CR in terms of a previous steady state weight and caloric intake.  For example if you had been weight stable on roughly 2500 Calories/day and you opt for 20% CR, ~2000 C/day your weight will fall and then stabilize at a lower weight.  And although weight is again stable continuing at that intake level would still be considered 20% CR.

 

This is somewhat a fuzzy concept since it doesn't take into account body composition.  I started from high body fat % and low lean mass.  My goal is to achieve and sustain a body fat of 10% - 12% and increase lean body mass.  If I don't achieve much gain in lean mass then my caloric intake will be quite restricted but with sufficient gain of lean mass it is possible I could end up eating as many calories as before.

 

Although this is an unconventional view/approach to CR it isn't without precedent.  One of the members here, Dean, now does a large amount of aerobic exercise and increased his caloric intake quite dramatically while sustaining a low bf%.  And I think he still considers himself CR'd.  I don't think there is enough info to say statistically what is the best approach to CR for longevity in humans.

Edited by Todd Allen

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Thanks for the reply; interesting!

 

And although weight is again stable continuing at that intake level would still be considered 20% CR.

 

Hmm... That seems to shift the discussion from restricting calories to something like:

1. the previous conventional wisdom was that the ideal weight or body composition was 'x' (pick your favorite metric: % body fat, waist-to-height ratio, BMI for all its faults, etc.)

2. the 'CR' community thinks the ideal is __% less than that

 

If one is constantly restricting calories to the point of hunger (which I gather is true in at least some of the animal studies), is that really weight stable? Seems unlikely -- though metabolism, hunger etc. have lots of aspects which aren't intuitive!

 

 

My goal is to achieve and sustain a body fat of 10% - 12% and increase lean body mass.

 

My goal (and part of the reason I stopped by here) is to figure out what % body fat is most likely* to promote longevity ... and then to increase lean body mass around that.

 

* granted, we don't know ... but each of us has to make a choice, so might as well sift from the best available evidence rather than rely on conventional 'wisdom' which seems to have gotten more wrong than right since the 1970s.

 

I look forward to other views!

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I am also one of the those who are eating moderate calories (around 2500 calories a day) and having a low BMI (17.5). I also don't exercise much, between 30-60 minutes of fast paced walking and 15-30 minutes of resistance training in a day on average. Other than this, I am pretty much sedentary i.e. sitting in the office during the day, though I try to keep sitting time as low as possible by standing up, going for tea or bathroom etc. This winter was a bit cold, I am guessing I spent lots of calories by just being in a cold room (10-15 °C with very light clothing) and it was intended of course.

 

What I am trying to say is that it seems there is not one way to have CR-like body markers. You can still have low BMI by eating more or have BMI around 22 by eating moderate and be perfectly healthy also. 

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My goal (and part of the reason I stopped by here) is to figure out what % body fat is most likely* to promote longevity ... and then to increase lean body mass around that.

 

* granted, we don't know ... but each of us has to make a choice, so might as well sift from the best available evidence rather than rely on conventional 'wisdom' which seems to have gotten more wrong than right since the 1970s.

 

I look forward to other views!

 

Actually, there are lots of studies on optimal BMI but none that I know, on optimal bodyfat. Even because we'd need not only bodyfat %age, but also bodyfat distribution, since lean people with lots of visceral fat (beer belly) are considered to exhibit an higher mortality than larger BMI sans visceral fat. Also, bodyfat type might also be a factor (BAT to non-BAT ratio?).

A BMI<25 is considered to be healthy, but that's not valid in very muscular people (a minority though) nor in beer belly types, waist circumference should always be used as a parameter together with BMI (and bodyfat %, I would add). 

 

A Good review by Luigi Fontana, 2014

 

Optimal bodyfat: we know that a bodyfat < 5% is hardly sustainable. Anorexic people and bodybuilders on the context day display such values. This is a lower bound. A more reasonable estimate would probably be in the region of 10-12% bodyfat for most men, according to body type, age. For ladies:  I don't know, definitely higher than guys. Optimum bodyfat for very active dudes might be 6-9%, sustainable usually only with prolonged activity and attentive dieting.

Edited by mccoy

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That is a great paper (which I read the other day). For the population at large, I agree that obese/overweight should get down to (for example) a more typical weight of a few generations ago. But that's just a starting point. For niche communities (CR, paleo/primal, longevity 'body hackers'), *many* questions remain.

 

e.g. 20% BMI (from the abstract) doesn't strike me as corresponding to CR (at least for males).

 

Or, to cite another number: "In most of these omitted studies, the BMI range associated with the lowest mortality was around 22.5–25". Surely that's not a typical range for CR?!?

 

Is Barak's 17.5 BMI probably healthier than 20? I'm pretty sure 'conventional medicine' would disagree. But, it wouldn't be the first time they were wrong!

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22.5–25". Surely that's not a typical range for CR?!?

 

 

This recent CR study --

 

Long-term calorie restriction in humans is not associated with indices of delayed immunologic aging: A descriptive study

 

 

--has info on the BMI spread of the CR group and the "normal weight" group.

 

 

Body Mass Index   [CR:] 19.07 (1.84) [15.37–22.55]a     [NW:]    23.27 (1.78) [18.87–24.96]b

 

Edited by Sibiriak

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I've just watched the following vid on a presentation from Aragon in Toronto. He illustrates his views and some literature on bodyfat.

 

It turns out that an ideal bodyfat range is 11-22% guys, 22-33% gals, according to recent literature, a range which optimizes health.

 

Olympic athletes exhibit a minimum of 6%, where there are bodyweight classes. Otherwise it's more.

 

Bodybuilders on day on context: 4.5% (with diuretics). According to Aragon, such low fat percentges are unhealthy and sometimes very risky.

 

I'd say that, for longevity reasons, the lower bound of such a range, 11%, may be adopted, 22% for gals. 

 

Edited by mccoy

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I just calculated my BMI and was termed overweight at 5'10", 192lbs with a BMI of 27.5 but my body fat is about 16% - this is why BMI frustrates me. (I had hydrostatic body fat testing to get body fat ratio)

My goal is also to cut more body fat and eventually add lean muscle - hoping once I get my bodyfat down a few more points I can increase calories a bit and hopefully start adding or at least maintaining lean muscle. 

Edited by nmonaco

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nmonaco, maybe you have a more-muscular-than-average frame, so your BMI is biased. Or greater than average bone mass.

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