Doesn't really turn the conventional approach on it's head, it's long been known that very obese people could lose a great deal of weight very quickly without adversely affecting FFM. There are also metabolic considerations which the amount of fat mass adjusts, which make fat people less prone to FFM loss while dieting (the converse is also true for lean people). This ties in with the whole leptin thing (though leptin is just a "part of the gang", not the kingpin, at least in humans), though there is definately something only semi-quantified by science about unprocessed grains and veggies that makes them "that much better" for weight loss - it's not just the fact that they're low GI, as low GI studies have not conclusively shown results beyond moderate GI, but I can definately tell the difference in the way I was dieting before and now in terms of weight and strength changes.
The conventional approach as has been promulgated to me is to increase deficits (whether through increased acitivty or caloric restriction) as BMR adjusts downward. This would be suggesting to start out with the highest deficit and decrease as your progress (after accounting for BMR adjustments). All this assuming that lean mass maintenance is the top priority.
That is not what I meant. I had always looked at the ability to easily diet hard when fat as mostly a matter of insulin resistance leading to a sparing of protein, ease of mobilization, etc (as you allude to). Here though they are obliquely dismissing all that and simply suggesting that it is quantifiable and more depending on release rates directly relates to total fat mass.
It makes a lot of sense. One could be on a strict ketogenic diet, eating a lot of saturated fat and using EC chronically; this would induce most of the same metabolic phenomenon present in the very fat. Yet if you are lean you will benefit from the same protein sparing effect due to the rate limiting factor. You could disregard the entire brain/energy state feedback cycle (leptin, etc) and produce a very simple explanation for all the difficulties lean people face getting even leaner.
Now, I am not actually saying cell signalling regardin energy states is not involved, just remarking using Occam's Razor with this research would allow the evolution of a simpler theory that has similar predictive capacity.
Of course, we are getting into observational abstractions at this point.
Most interestingly to me are the numbers!
Assuming there is validity to the study, 20lbs of fat = "safe" deficit of ~600Kcal a day! Every lb of adipose correlating to 30Kcal of deficit per day!
I did not realize you have to be logged in to Lyle's board now, so here is the abstract; never got the full thing:
J Theor Biol. 2005 Mar 7;233(1):1-13. Epub 2004 Dec 8.
A limit on the energy transfer rate from the human fat store in hypophagia.
Alpert SS.
Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131-1156, USA.
[email protected]
limit on the maximum energy transfer rate from the human fat store in hypophagia is deduced from experimental data of underfed subjects maintaining moderate activity levels and is found to have a value of (290+/-25) kJ/kgd. A dietary restriction which exceeds the limited capability of the fat store to compensate for the energy deficiency results in an immediate decrease in the fat free mass (FFM). In cases of a less severe dietary deficiency, the FFM will not be depleted. The transition between these two dietary regions is developed and a criterion to distinguish the regions is defined. An exact mathematical solution for the decrease of the FFM is derived for the case where the fat mass (FM) is in its limited energy transfer mode. The solution shows a steady-state term which is in agreement with conventional ideas, a term indicating a slow decrease of much of the FFM moderated by the limited energy transferred from the fat store, and a final term showing an unprotected rapid decrease of the remaining part of the FFM. The average resting metabolic rate of subjects undergoing hypophagia is shown to decrease linearly as a function of the FFM with a slope of (249+/-25) kJ/kgd. This value disagrees with the results of other observers who have measured metabolic rates of diverse groups. The disagreement is explained in terms of individual metabolic properties as opposed to those of the larger population.
PMID: 15615615 [PubMed - indexed for MEDLINE]
Anyway, regarding the GI stuff. I think you have misconstrued my position, Ex, if you think I am advocating high GI as I certainly am not.
What the calorie = calorie arguments overlook are:
Increased insulin sensitivity from fiber and MUFA/PUFA dominant fat intake
Satiety/appetite control
Vitamin / mineral content
Emotional / psychological state
Fewer "toxins" in the system using unprocessed food choices
And probably more factors, not the least which is just having substrate distributed to the body at a stable pace rather than pulses.
I totally agree regarding the unquantified differences in diet and results and also think it does transcend glycemic response issues. I think we can make some intelligent guesses though and I would look first at the side effect of achieving low gi.
Invariably, it ends up that low gi = unprocessed foods. So, veggies, some fruits, legumes, nuts, a few grains like barley (we all now the list). Yes they are low gi, but also these foods are the most dense sources per calorie of vitamins / minerals, phytonutrients (many of which are "undiscovered"), antioxidants, healthy fats etc.
You mention strength and this is something I have noticed as well. Running a deficit, but still taking 150-200g carbs a day in the form of veggies (ends up being 3-4lbs of roughage) with a starch at breakfast, I have been able to even to easily maintain strength and endurance performance and even make small strength increases!
With the actual mechanisms of CNS and motor unit fatigue so poorly elucidated (as far as I know anyway) at this point, I wonder if maintaining such a rich substrate from veggies and whole grains enhances a rate limiting mechanism in recovery from CNS fatigue. I don't think there are any studies looking at this directly, but my gut tells me there is a link.
When you can't quantify it though, it does make it tougher to argue with people who insist that you would get the same dieting results by eating at McDonald's (and they are out there).
I would like to continue, but I got to get my ass back to work!