I SAW MY first bodybuilding show in the early 1980s. It was an amateur contest in St. Louis, my hometown. The range of physiques on display was astounding. One guy had the widest shoulders I’d ever seen, with deltoids that looked like twin moons in partial eclipse. Another – a compact former powerlifter competing for the first time – had muscles that seemed impossibly dense. Even the also-rans had distinct strengths and weaknesses.
The highlight, though, was a guest posing routine by Tom Platz, a pro bodybuilder with thighs that were easily the size of my waist at the time. His legs reminded me of those pictures we used to draw in grade school of cars with jet engines. It had never occurred to me that a human could pack on that much muscle.
I knew little about diet and training, and even less about genetics and steroids. All I saw was a ton of muscle, and I wanted to know how to get more. Thirty years later, I’m pretty sure I know – and it’s not at all what I expected.
The Upper Limits
In The Sports Gene, author David Epstein offers a clear answer to the question of how much muscle any individual can pack onto his frame: five pounds for every pound of bone.
Unfortunately, you’d need a DEXA scan to figure out how much muscle and bone you have now – and, by extension, how much more you could gain if everything worked out exactly right.
Research typically tackles the question with short-term training programmes, often with one group using a nutritional supplement and the other getting a placebo. Stuart Phillips, Ph.D., who has conducted many of these studies at McMaster University in Ontario, says he expects the average subject to gain 4 to 7 pounds of muscle in three months.
No matter how good the programme or supplements are, he rarely sees average gains exceeding about half a pound a week.
Individuals, he notes, can show more extreme results. One guy might gain 15 pounds, while another doesn’t build any measurable amount of muscle. But the average still lands around 4 to 7 pounds.
Moreover, Phillips adds, the gains in the first 12 weeks of training are a very good indication of overall potential. ‘I’m not saying guys can’t put on muscle with more than 12 weeks of training, but you see a good deal of what people can do in that time. More importantly, if you’re a hard gainer in those 12 weeks, then you’re a hard gainer, period.’
To Phillips, the reason for the disparity in results – the difference between a textbook hard gainer like me and the bodybuilders on that stage – is ‘90 per cent genetics’.
Genetics and Muscle Growth
With all the tools we have to manipulate diet and training programmes, and all the ways lifestyle choices affect your physique, it’s hard to believe genes play such an outsized role in the results. We accept that genetics determine our height and hairlines – but our muscles?
Start with satellite cells. These are stem cells within your muscles that provide extra nuclei, giving them a more powerful growth stimulus. The only way to know how many satellite cells you have would be to take biopsies of the muscles and run sophisticated – and presumably expensive – tests.
That’s what researchers at the University of Alabama at Birmingham did for a 2008 study in the Journal of Applied Physiology.
They found that the relative number of satellite cells predicted who would gain the most muscle over a 16-week training programme. A quarter of participants didn’t gain any muscle at all in their quadriceps, while another quarter increased their quad mass by more than 50 per cent.
So if nothing else, we can conclude that Tom Platz – the bodybuilder with turbines for legs – started with a ridiculous load of satellite cells.
Muscle-building potential isn’t entirely invisible. Sometimes you can look at someone before they start training and see the potential.
A guy who looks athletic, with wide shoulders and a frame that doesn’t disappear when he turns sideways, will probably look even more so after time in the weight room.
The converse is someone like me. In my teenage years, even fat guys thought it was fair to make fun of my skinny arms and legs. The size and shape of those muscles is limited by the length of tendons relative to the length of bones.
Think of your biceps. A bigger muscle belly will have a shorter tendon connecting it to the forearm. The most genetically gifted lifter will have biceps that appear to begin right at the elbow joint; when flexed, there’ll be little, if any, space between upper- and lower-arm muscles.
Individual muscles aside, when we talk about building muscle, we’re often also talking about gaining weight. That requires eating more than your body needs to maintain its current size – and involves a different, but equally complex, set of variables.
Clean vs Dirty Bulking
It’s easy to gain weight if you don’t care what kind of weight you gain. But most guys who think it through will opt for a ‘clean bulk’ – aiming to add muscle with minimal fat.
Alan Aragon, my co-author on The Lean Muscle Diet, estimates that an entry-level lifter can gain 2 to 3 pounds of muscle per month without adding much fat. An intermediate can gain 1 to 2 pounds a month, and an experienced lifter will be lucky to add half a pound.
There’s also the ‘dirty bulk’, in which you lift hard and eat anything that doesn’t move fast enough to get out of your way. How much you gain during a phase of overfeeding – and how much of it is muscle – depends on two key variables.
The first is how lean you are to begin with.
Dr Gilbert Forbes, a pioneer in the study of body composition, showed that fat and lean tissue tend to increase or decrease in relation to each other. When a lean person overeats, a greater proportion of the weight gained is lean tissue. The opposite is true for someone with higher body fat, who will typically gain proportionally more fat.
But there’s a lot of individual variation – and, again, your genes seem to be running the show.
Perhaps the most notable weight-gain experiment ever conducted began in the late 1980s at Laval University in Quebec.
The research team took 12 pairs of identical twins, all relatively lean but sedentary young men, and overfed them for 100 days. The average increase was 18 pounds – about two-thirds lean tissue and one-third fat – but the range was from 9 to 29 pounds. The strongest predictor of how much an individual gained was how much his twin gained (genes also influenced where they stored fat).
Why didn’t everyone gain the same amount of weight? In a 2014 study in the International Journal of Obesity, researchers found that those with the highest VO2 max (a measure of aerobic fitness) and the highest percentage of Type I muscle fibres (responsible for long-duration, low-intensity work) gained the least weight, with the highest proportion of lean mass.
On the flip side, men with a higher percentage of Type II muscle fibres – the ones responsible for speed, strength and power – gained more weight overall, along with a higher proportion of fat.
The same applied to men whose muscles had the greatest glycolytic potential – a measure of their ability to produce energy during high-intensity efforts. For most people, this system fuels all-out efforts lasting 30 to 60 seconds (although well-trained athletes can extend that window).
In short, men predisposed to endurance tended to gain less weight and less fat when overfed, while those wired for strength and power gained more – including more fat.
That’s the good news for hard gainers. And for men naturally suited to lifting or sprinting, it helps explain why they can gain size easily – but not always cleanly.
If you’d told the younger, skinnier me all this 30 years ago, as I watched those bodybuilders on stage, I wouldn’t have believed you. How could these huge guys be so lean if their bodies were also primed to gain fat?
The obvious answer is that they trained hard to build muscle and dieted hard to strip fat. The subjects in the Laval University study were sedentary, so we can’t say exactly how lifting would have changed their results – only that they likely would have gained more muscle and less fat.
But there was another factor in those physiques that I didn’t fully understand at the time.
The Role of Steroids
The first studies linking synthetic testosterone to increased muscle and strength were published in the early 1940s. But it wasn’t until the mid-1950s that anabolic drugs were clearly and permanently linked to sports performance.
Americans dominated weightlifting in the early post-war years. But in 1953, the Soviet Union won its first world championship, and in 1954 a doctor for the Soviet team admitted to his American counterpart that his athletes were injecting testosterone. That American doctor, John Ziegler, went on to develop Dianabol, the first oral steroid, and Winstrol, an injectable.
You know the rest of the story. By the 1960s, steroids were widespread in strength and power sports, from the Olympics to the NFL. They were especially influential in the fast-growing worlds of powerlifting and bodybuilding. But at the time, only insiders in sport, fitness and exercise science fully understood how important they were.
The fitness industry – where I was just beginning to find my way – had a vested interest in blurring the line between natural potential and pharmaceutical enhancement.
Who would read about Mr Olympia’s sleeve-busting biceps workout if it also included a list of the illegal, expensive and potentially dangerous drugs he used to build arms the size of his head?
The article might mention supplements – especially if they were sold by the same company publishing the magazine – but would mostly focus on familiar exercises, just with heavier weights and bigger physiques.
In sport, athletes benefited from a generation of writers who didn’t train and didn’t fully understand what was achievable without drugs. My favourite example is a Baseball America article from 2002. Under the subhead ‘Raw Talent Takes Time’ is this line about José Canseco’s transformation:
‘But 1985 saw a different Canseco. Already considered less than focused, he matured dramatically after coming to grips with his mother’s death early in the previous season. He also added 30 pounds in offseason workouts.’
That line wasn’t highlighted in the original – it was simply dropped into a story about his jump from 15 home runs in 1984 to 36 in 1985, before going on to become AL Rookie of the Year in ’86 and MVP in ’88.
You’d think that by 2002, no sportswriter would still be naïve about steroids. Canseco himself had begun talking openly about his use. But then, as now, the narrative of athletes overcoming adversity is more compelling when you leave out the chemistry.
So what exactly do steroids add to conventional training?
A landmark 1996 study in the New England Journal of Medicine found that men using testosterone gained significantly more muscle and strength than those following the same training and diet without it. In just 10 weeks, the testosterone group added around 13 pounds of lean mass, compared to roughly 4 pounds in the placebo group.
Phillips sees this as a clear illustration of the gap between natural and enhanced training outcomes. An average lifter might gain 4 to 7 pounds of muscle in 10 to 12 weeks – typically only if they’re new to training or returning after time off. The more experienced you are, the slower progress becomes.
It’s possible for an individual to gain more – just as it’s possible to gain nothing at all. But those cases are outliers.
So if you come across a training plan or supplement promising results far beyond these benchmarks, there’s a simple explanation: it doesn’t hold up.
