The Question

A long-standing question in my mind has been, “What is the optimal (or maximal) deficit for a fat loss diet?” Yes, I know I’m not the first to address the issue but I’ve always wondered if we couldn’t figure out exactly what an optimal deficit might be on a diet, rather than relying on annoying trial and error.

I’m sure readers are familiar with previous approaches but let’s run through them quickly. The simplest (read: totally retarded) method of setting calories on a diet is to give everyone some fixed amount. Usually women get 1200, men get 1500. How such an intake can magically be correct regardless of bodyweight or activity, I have no idea. But apparently a 300 lb man and a 150 lb man should both eat an identical amount and that amount is 1500 calories/day when they diet. Amazingly, in 2006, that kind of moronic stuff is still out there.

The second approach is along the lines of, “To lose one pound of fat per week, eat 500 calories/day less than your maintenance; to lose 2 pounds, eat 1000 calories less per day.” Simple math, although not entirely correct for a variety of reasons I don’t want to get into. I addressed problems with both approaches in the big Ketogenic Diet book.

In Bodyopus, Dan Duchaine (who was writing for lean folks, remember) recommended a maximum deficit of 20% below maintenance. Better, as this at least scales the deficit relative to maintenance. A big ass guy with a 4000 calorie maintenance gets a larger deficit (800 cal/day) than a small female with a 1700 calorie maintenance (340 cal/day). Of course, weekly fat/weight loss will be significantly different for the two, which seems to pass the reality check. Bigger males do lose more fat than smaller females. I regularly advocate this approach.

In the Ketogenic Diet book, I suggested setting a deficit based on current total bodyweight, since most people have trouble figuring out their true maintenance intake. Assuming an average maintenance intake of 14-16 cal/lb (you can use 15 cal/lb and split the middle), a 20% deficit yields ~11-13 cal/lb (and 10-12 cal/lb for dieting has been around in the bodybuilding world for at least a decade), which will then have to be adjusted based on real world results. Some people, for example, with low daily activity and shitty genetics, may have to go to 8 cal/lb AND do aerobics to lose fat effectively. Back when I was lifting twice/week and doing fuckall else activity, I had to do that. Now that I’m training 16-20 hours/week, I get to eat more when I diet. Hooray. In the two new books (The Rapid Fat Loss Handbook and A Guide to Flexible Dieting (you should BUY THEM NOW), I offer my personal scheme for adjusting intake based on what’s happening to bodyweight and strength levels in the gym.

$AD$

Now, empirically and based on research, it’s well established that…

a. fatter individuals lose more fat and less lean body mass (LBM) than leaner individuals; and
b. bigger individuals lose weight more quickly

By corollary, smaller/leaner individuals not only lose total weight/fat at a slower rate, they lose a greater proportion of LBM. The whole issue of calorie partitioning has been discussed to death in my various books, especially The Ultimate Diet 2.0.

It’s why those fat asses on “The Biggest Loser” can drop 8-10 lbs. a week, well at least for the first week (and some of that is certainly water, glycogen and clearing the shit out of their bowels), and someone at 12% bodyfat may struggle to drop one pound per week without sacrificing muscle.