The reason I was asking about time frames - dropping 20 lbs of fat in 8 weeks versus 20 weeks - is due to what I tend to see from people opting for the more aggressive ' 20 lbs. in 8 weeks ' option ( and I'm assuming this is for people who have had some training experience and had seen some gains in lean muscle mass etc. )
In your mind, what is the signifgance of, "I'm assuming this is for people who have had some trianing experience and had seen some gains in lean muscle mass." ?
Granted, this is a broad generalization, but from what i've seen, my sense has been that when people are trying to drop a good amount of fat rather quickly, the first line of attack is to create a BIG calorie deficit by cutting back on the intake of food calories, ramping up expenditure of calories via A LOT of extra cardio - or both.
Now, there's nothing wrong with either approach ( done prudently ) as part of any fat loss plan, but, human nature being what it is ( i.e people are
very impatient

) I tend to see people getting overly " aggressive " in the magnitude of the food calorie deficit they undertake as well as the amount and intensity of the extra cardio they tack on ( they want to lose fact yesterday ! )
And, when they do that - i.e slashing calories and ramping up cardio - it's the greatly enhanced risk of losing muscle mass along the way that becomes more serious an issue as a result.
If carbs take the bulk of the calorie slash hit from food and ( as a result of more and cardio ) the glycogen stores in the liver and muscles aren't sustained as they should be, the cortisol levels jump and more and more protien / muscle tissue gets used for convertion to glucose.
I don't understand how any of this is relevant to my statement. The rate at which you lose fat and maintain muscle is mostly dependent on your level of body fatness.
Here, you bring up one particular instance, out of literally thousands that you could create, where an individual is low carbing, low cals, doing lots of cardio....blah, blah, blah.....
Yea, and?
I am not trying to be a wise guy.... but n=1 is no way to prove your point here. I don't even know if I am seeing your point. I have yet to read on, so let me see whatelse you have to say:
Now, I know from your other posts you've suggested that a way to try and avoid this from happenig when ' cutting ' fat is to increase protein intake - bump up the amount of amino acids so any cortisol triggered creation of glucose comes from a larger amino acid pool and not from canabalizing muscle tissue. I agree with that as it makes perfect sense - if you want to slash fat, keep don't skimp on protein.
This is correct. A few other variables must be in place, but I think elevating one's protein intake is critical on any diet.
So, getting back to the point, I guess what I''m saying is that it isn't so much " how much fat you are currently carrying " but how fast you want to lose it.
So because ONE person might be low carbing/cal, that means what matters most is how fast you want to lose the fat? I don't see the correlation.
My view is that, if you take 20 weeks to try and lose 20 lbs instead of 8 weeks, the issue of muscle catabolism due to the onset of higher cortisol levels ( from the glycogen issues and stress an aggressive 8 weeks may trigger ) is less of an issue....the need for A LOT of cadio and a BIG food calorie cut simply isn't needed if your time frame is to lose fat over 20 weeks.
This is a moot point. Why?
Because you are not taking into account starting body fat levels. Which again, is the primary dictator of how *hard* you can diet without losing muscle.
Now, I'm a layman at this, and you have more expertise at this than I do do....so I welcome your opinion on this based on your experience with cilents.
My experience suggests otherwise from what you suggest, that time dictates rate. The fatter individuals I've trained can do very insane caloric cuts from their maintenance without having a negative effect on muscle mass.
The physiology of a fat person is a bit different than that of their leaner counterparts. You seem to be simplifying the body on solely the basis of cortisol. What about the other hormonal constituents that play major roles on dieting and body fatness?
Overweight people can handle a deeper caloric deficit without running into the problems often times associated with cutting calories by too much in average individuals (ie. hormonal disruptions to insulin, ghrelin, leptin, peptide YY, muscle loss, stalled fat loss, etc). The leaner you get, the more careful you have to be.
This is why it's not the time you have to lose the fat that is the liimiting factor, but rather, it's how fat you are currently.
But, let's say you had 2 clients who had put on some muscle mass over a year or so. Now, both want to lose fat in a hurry. One client is at 14% body fat. One is at 26% body fat. They both wanted to, for example, lose 20 lbs in 8 weeks. I think you are saying that the 26% client will lose fat FASTER than the 14% client.
I am not saying that he will.
I am saying that he can. It is up to him (personality traits, etc) that will determine if he chooses to.
But, are you also saying that a protocol of large calorie cuts from food and extra calorie expenditures due to cardio ( and I'm not saying you would recommend this - assume they do it on their own

) would effect them differently in terms of muscle loss ? In other words, it would put the them at
different risk levels for loss of muscle ?
Bingo.
Fat people can do pretty insane things when it comes to losing fat without losing muscle, as I stated above.
In simple terms, fat tissue = leptin signaling.
The more bodyfat you have, the harder it is to get the body to think it's underfed, thus, the traditional physiological suvival mechanism do not kick in as hard in big people as they would in their leaner counterparts.
I can't give you any guidelines like, "If person Y is X% BF, how hard can he diet."
But with my clients who are desiring weight loss, body fat level is one of the primary factors that plays into how drastic of an energy deficit we will use.