Lyle wrote an article based on conversations with me, Alan Aragon and Casey Butt, with regards to the maximum muscular potential of natural lifters and realistic rates of muscle gain.

Here’s my take on the issue.

Martin Berkhan of has a somewhat simpler model than Casey’s, also based on his observation of top level natural bodybuilding competitors who are contest lean (e.g. 4-5% body fat)

His equation is:

Height in centimeters – 100 = upper limit of weight in kilograms in contest shape.

So take your height in inches and multiply by 2.54, that’s your height in centimeters. Subtract 100 and that’s your predicted maximum weight in contest shape (which is 5% body fat or less for males) in kilograms. Multiply that value by 2.2 to get pounds. So let’s look at body weight at 10% body fat using the same heights I used for Casey’s calculator. I’ve also calculated out lean body mass at 10% body fat.

Height Weight at 5% Body Fat Weight at 10% Body Fat Lean Body Mass
5′8″ 160 lbs. 170 lbs. 153 lbs.
5′10″ 171 lbs. 180 lbs. 162 lbs.
6′ 182 lbs. 192 lbs. 173 lbs.

While not identical, these values are certainly right in line with Casey’s calculator. I would note that contest lean bodybuilders are often highly dehydrated and may be glycogen depleted and this will tend to lower the measurement of lean body mass. We might realistically add 5-10 pounds of lean body mass to the above values to account for dehydration/etc. With that adjustment, they are more or less identical to Casey’s values ”

Full article here

In addition to the above statement, I should add that while natural trainees tend to lose some lean body mass while venturing into the lowest bf% achieveable, this is more of typical scenario as it has pertained to the natural bodybuilders I have either spoken to or worked with.

I have also had clients hitting 5-6% body fat with 100% strength maintenance, indicating that no lean mass was lost. The main variable here is the time line, and a slower approach is superior to a faster approach, with regards to lean body mass maintenance when dieting in the single digits. Bodybuilders working against time may not be able to afford the luxury of a slow approach, which in turn may compromise lean body mass in the final weeks. According to my experience, going from lean to shredded, without sacrificing muscle mass or strength, is certainly possible with enough patience, and the right diet and training regimen.

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