Calorie Restriction or Protein Restriction?

[JeffN]

Calories or Protein? The effect of dietary restriction on lifespan in rodents is explained by calories alone.
Speakman JR, Mitchell SE, Mazidi M.
Exp Gerontol. 2016 Mar 19. pii: S0531-5565(16)30069-9. doi: 10.1016/j.exger.2016.03.011. [Epub ahead of print]
PMID: 27006163

http://linkinghub.elsevier.com.sci-hub. ... 6516300699

Abstract

Almost exactly 100 years ago Osborne and colleagues demonstrated that restricting the food intake of a small number of female rats extended their lifespan. In the 1930s experiments on the impact of diet on lifespan were extended by Slonaker, and subsequently McCay. Slonaker concluded that there was a strong impact of protein intake on lifespan, while McCay concluded that calories are the main factor causing differences in lifespan when animals are restricted (Calorie restriction or CR). Hence from the very beginning the question of whether food restriction acts on lifespan via reduced calorie intake or reduced protein intake was disputed. Subsequent work supported the idea that calories were the dominant factor. More recently, however, this role has again been questioned, particularly in studies of insects. Here we review the data regarding previous studies of protein and calorie restriction in rodents. We show that increasing CR (with simultaneous protein restriction: PR) increases lifespan, and that CR with no PR generates an identical effect. None of the residual variation in the impact of CR (with PR) on lifespan could be traced to variation in macronutrient content of the diet. Other studies show that low protein content in the diet does increase median lifespan, but the effect is smaller than the CR effect. We conclude that CR is a valid phenomenon in rodents that cannot be explained by changes in protein intake, but that there is a separate phenomenon linking protein intake to lifespan, which acts over a different range of protein intakes than is typical in CR studies. This suggests there may be a fundamental difference in the responses of insects and rodents to CR. This may be traced to differences in the physiology of these groups, or reflect a major methodological difference between 'restriction' studies performed on rodents and insects. We suggest that studies where the diet is supplied ad libitum, but diluted with inert components, should perhaps be called dietary or caloric dilution, rather than dietary or caloric restriction, to distinguish these potentially important methodological differences.

[geo]

Thank you for this paper, it is fascinating reading. I especially like the fact that they recommend acknowledging the difference between CR (Caloric Restriction) and CD (Caloric Dilution). I've never felt comfortable calling the MWL a caloric restricted diet because it essentially isn't. And even caloric dilution is not quite right as it implies a purposeful effort to reduce calories. MWL is so much more than just about calorie dilution though that may be its most obvious trait to many. To my mind the MWL is quite simply nothing more than a simple yet completely natural way to fuel our bodies the way evolution originally intended before we became too smart for our own good

I also just read the link you provided above to "Michael" (http://www.longecity.org/forum/topic/51 ... dian-diet/) who seems to have gone all crazy on following the path of studies and micro-managing every last macro/micro/phyto nutrient and particular food stuff to the Nth degree in his quest for CR life extention. Its too bad he has followed the path of reductionist science so well, (despite missing so much of the good science) but yet, I believe, have failed to see the big picture that shows the true simpicity of it all.

Thank you again for seemingly being the only one to think rationally about the subject of CR and overall nutritional health in both the proper context and perspetive (i.e., the big picture instead of reductionism).

[JeffN]

MWL is so much more than just about calorie dilution though that may be its most obvious trait to many. To my mind the MWL is quite simply nothing more than a simple yet completely natural way to fuel our bodies the way evolution originally intended before we became too smart for our own good .

Agreed.

It is interesting how, over the years, and in time, so many of the professionals in this field have come to realize this. You can see it incorporated more and more into messages, presentations, writings, etc. And, as we know from posts here, many here are not able to fully reach their health and/or weight goals till they implement the principles of calorie density.

Thank you again for seemingly being the only one to think rationally about the subject of CR and overall nutritional health in both the proper context and perspetive (i.e., the big picture instead of reductionism).

Thanks.

In Health
Jeff

[JeffN]

Decreased Consumption of Branched-Chain Amino Acids Improves Metabolic Health.
Fontana L, Cummings NE, Arriola Apelo SI, Neuman JC, Kasza I, et al
Cell Rep. 2016 Jun 21. pii: S2211-1247(16)30733-1.
doi: 10.1016/j.celrep.2016.05.092.
PMID: 27346343 Free Article

Full Text
http://www.cell.com/cell-reports/pdfExtended/S2211-1247(16)30733-1

Abstract
Protein-restricted (PR), high-carbohydrate diets improve metabolic health in rodents, yet the precise dietary components that are responsible for these effects have not been identified. Furthermore, the applicability of these studies to humans is unclear. Here, we demonstrate in a randomized controlled trial that a moderate PR diet also improves markers of metabolic health in humans. Intriguingly, we find that feeding mice a diet specifically reduced in branched-chain amino acids (BCAAs) is sufficient to improve glucose tolerance and body composition equivalently to a PR diet via metabolically distinct pathways. Our results highlight a critical role for dietary quality at the level of amino acids in the maintenance of metabolic health and suggest that diets specifically reduced in BCAAs, or pharmacological interventions in this pathway, may offer a translatable way to achieve many of the metabolic benefits of a PR diet.

"Here, we demonstrate that a moderate reduction in total dietary protein or selected amino acids can rapidly improve metabolic health in both humans and mice. Reduction of dietary protein or total amino acids decreases fasting blood glucose levels and improves glucose tolerance in both species in less than six weeks, while also decreasing BMI and fat mass in humans and decreasing weight and fat mass gain in young growing mice."


Comments...

If you look at table S1 in the Supplemental Material, the protein restricted group consumed about 64 grams of protein a day (which was 8.9% of calorie), well above the general RDA of 55 gm/day for an Adult male & 45 gm/day for an Adult female.

Knowing their BMI was 29.9, their weight 217, we can assume their height about 71.5 inches and use these numbers to make the following estimates....

Using the protein per body weight formula (.8g/kg):

Using the current weight and the obesity adjusted formula for protein needs, it comes out to 69 grams.

We don't have to feed their excess fat protein, so If their BMI was 25 (which is still heavy), they would weigh about 180, which would make their protein needs about 65. If their BMI was 22 they would weight about 160, which would make their protein needs about 58.

Using the current weight and the obesity adjusted formula for protein needs at a BMI of 22, it comes out to 63 grams.

While these are all only estimates based on the 19 subjects, which is the best we can do right now, I would not consider any of these numbers "restricted" but more RDA level.

In Health
Jeff

NOTE The obesity adjusted weight formula (OAW = [Current weight - ideal body weight] x .25 + ideal body weight = Obesity Adjusted Weight) is used in ICU and CCU's where patients need to be fed by TPN or PPN and they are not trying to have the patient lose weight, and so usually overestimates protein needs. I usually just use a normal/ideal body weight.

[geo]

Its interesting that the closer they got to what are RDA levels for protein, the more biomarkers improved. It does make one wonder whether more improvement can be found in going below RDA levels. We do know that Dr Kempner's Rice diet provided 50% or less of RDA protein levels with exceptional results. And I once read (40 years ago) about an African Tribe that was studied that was particularly disease free that averaged about 28 gm/day of protein. The problem is, even with the MWL, its really difficult to get to these extremely low levels of daily protein and maintain what most might call "normal" caloric levels. I do wonder if protein levels between 25-50 gm/day maybe more optimal, even considering possible need for more at higher activity levels.

One question: I've noticed studies using both Total Body Mass and Lean Body Mass when describing protein needs. Obviously, fat does not require protein, but measuring LBM accurately can be extremely difficult. Do you think its better to express protein needs in terms of LBM since fat mass can very so much in individuals?

[JeffN]

It's possible but my point in emphasising that most of what is being done is really *moderation* & not really a *restriction* is because everyone is looking for a hack/shortcut and may not get what's really being tested in these studies. Also at a BMI of 30, I don't think what they were doing in this study's would truly qualify as CR.

Kidney patients are often put on a diet that is "restricted" to about half the RDA but that's to try & keep them alive and usually has to be maintained to do so. I've written about this in this forum in regard to the results of resistance training on increases in strength & muscle on these patients.

Kempner deliberately used 20-25 grams of protein to keep protein as low as possible during the main intervention stage as again, with his patient population, had no choice. However, once past the main intervention stage the diet was liberalized.

There are published records of subjects going up to 6 months and even a year on water alone, which would be the ultimate in exogenous protein restriction but again, only as interventions and in these cases, they are usually extremely obese.

So, maybe .... but not sure it's been attempted as a true "CR" life extension strategy but only as a healing intervention, usually for a limited time. Saving a life about to be cut short is important and I think the results of the above study are also important but it's not the same as life extension in regard to CR.

To me, the main message of the above is excess protein above adequate, is not necessary and even harmful.

Sounds like a familiar tune

In Health
Jeff