Lorne, the abreviated version directly from JB’s mouth:
"Too Fat to go on a Mass Phase?
"Q. You’ve written before that going on a mass phase isn’t a good idea for a person who isn’t already lean because this leads to rapid fat gain. So how lean should a person be before cranking up the calories?
"A. Based on empirical results (what I’ve seen in the gym) and the research I’ve discussed in a previous column, it’s clear that one of the biggest determinants of your muscle loss to fat loss ratio (when dieting) and your muscle gain to fat gain ratio (when bulking up) is your initial level of body fatness. Generally, the amount of body fat that you have (percentage and total pounds of fat) will be a major determinant of how your body responds to over-eating or under-eating. Stated another way, if you’re fat, you shouldn’t try to bulk up because you’ll gain mostly fat. But how much body fat puts you into the “too fat to bulk” category?
"As I pointed out in one of my previous columns, subjects who started overfeeding with 22 lbs of fat on their bodies gained 70% of their weight as lean body mass and 30% of their weight as fat mass (To put this into perspective, your stats would have to be something like 150lb at 15% or 200lb at 11%).
"However, double those body-fat numbers (150lb at 30% or 200lb at 22%), and the ratio flops in the opposite direction (30% lean body mass gain and 70% fat gain). With these data, it doesn’t take too much of a leap to deduce that the 50-50 point would be around 33 lbs of fat (150lb at 22% fat; 200lb at 17%).
"Now that you have these numbers, it’s your turn to decide what’s too fat to bulk. Ideally a 100% lean body mass gain is what we’re all shooting for. But that isn’t very realistic. In my opinion, a 70% lean to 30% fat gain is as far as I’m willing to go. And this fits right in line with my stats as I normally fluctuate between 5% fat and 12% fat throughout the year.
"Therefore, I’ll begin an overfeeding phase at 5% and bulk up to 10-12% fat. At this point, I begin to dislike how my physique looks. Conveniently, according to the data, the lean gain to fat gain ratio begins to decrease and more fat would be accumulating should I continue to overfeed.
"But I’m partially lucky as I was blessed with decent “leanness” genetics. I know people who’ve never seen 5% despite valiant efforts. For them they may need a more liberal standard to follow.
“Now that you’re armed with the information, go ahead and decide for yourself what’s “too fat to bulk” based on the projected fat and lean gains derived from your own weight and body fat percentages.”