But this does not explain the whole picture. I would argue that it is more important to keep to a good diet for maintenance of bodyweight vs. relying on some predetermined set of lean body mass. Our basal metabolic rates are only going to get us so far. Regardless of how fast it moves, eventually, it will not like donuts...
And to be sure, there is very little about (real) bodybuilding (aka sarcoplasmic hypertrophy) that is healthy. Your kidneys take a big hit every time you scale up or down and lord only knows what your lipid panel is during competition time. Muscle, albeit not the same compound, eventually becomes a fat container. You ever seen a stocky muscular young man grow up to be a thin lean muscular silverman? Not here...
I agree that getting more activating muscles via recruitment (aka myofibrillar hypertrophy) is overall the best exercise plan, but nothing changes your body, mind, and spirit like a well balanced, healthy, calorie-controlled diet. The most telling example are those faithful gymgoers that hog up the equipment at the gym, working like slaves, and have no noticeable change in body composition over several years.
It is very common for the person to describe their diet as "Crap because I [insert your favorite excuse] ->can't cook, work long hours, am big boned, am under a lot of stress.
Diet Dude, Diet
Replying to both you and Nasrudin here. Myofibrillar hypertrophy doesn't require (and in some ways can prohibit) large gains in total mass. We are not talking about Arnold or even the typical action hero build here, but something rather more modest; in the 'overweight' range of BMI rather than the 'obese' range. Think male in the 170s at 5'11 or so.
Sarcoplasmic hypertrophy refers to an increase in the volume of the non-contractile elements of muscle. Glycogen, endoplasmic reticulum, mitochondria, ribosomes, golgi bodies. That sort of stuff.
Myofibrillar hypertrophy on the other hand refers to an increase in the density and total weight of contractile elements of muscle tissue. The good stuff.
A typical strength-focused protocol might involve SOME mass gain especially in early years, but is typically structured in a way that you can continue to train for the rest of your life and gain relatively little in overall volume and mass beyond a certain point (fat free mass index of 20-23 generally speaking). I have been hitting the iron like it was my life (and in some ways it saved mine) since the age of 19 or so. In that decade, I've gained something like 10lbs. Most of it before I was 21 and probably more attributable to hormonal maturity rather than my training. This isn't atypical, and strength athletes looking to add significant bulk usually have to use non-strength-based protocols to do so.
The contractile portion of muscle is responsible for a heck of a lot of important stuff both functionally and metabolically.
From a functional perspective, our musculoskeletal system is composed of passive and active players, with bones and connective tissue comprising the passive parts while muscle takes on the active role. The reason that strength-based protocols have consistently been found to reduce the pain of arthritis is because it improves joint function through improving the active component (there's an increasingly large corresponding body of evidence indicating that it is maladaptive locomotor and activation patterns in muscle that is responsible for OA in the first place).
Sarcopenia is now understood to be a major predictor of declining function in everything from cognition to pain to basic longevity. Those of us with greater myofibrillar density will see a correspondingly slower decline in total lean body mass over time, and more importantly, what we do keep, we'll use better. Contrary to popular opinion, the pre-steroid era strongmen (especially those who maintained relatively normal bodyweights) lived very long, very active lives, doing things in their 70s that most of us couldn't in our 20s. Cardiovascular exercise has little effect on lean body mass and most studies have found that avid cardio people don't seem to live that much longer than sedentary individuals. Unfortunately, the waters of weight-lifting are so polluted by bodybuilders as to be effectively useless when it comes to attempting a longevity study using this population, but anecdotal evidence is pretty strong nonetheless.
Metabolically, muscle, and in particular muscle-building activity has a lot of important effects. At a very basic level, lean body mass raises your basal metabolic rate. You have a larger caloric budget. It also has much greater EPOC (excess post-exercise oxygen consumption) than aerobic exercise. At around 3000 calories per day, at a maintenance weight, I have a significantly larger caloric budget than most and this shows in the sheer amount of junk food I eat while maintaining a 10 or under percent body fat.
Muscle also improves insulin sensitivity; it's the most important variable when it comes to that. And as we know insulin sensitivity determines a broad range of functioning most likely due to the global effects of elevated blood sugar on microvascular and immune health throughout the body. Although that said, insulin sensitivity seems to have a direct effect on nervous system (as well as muscle) function.
Finally, muscle, and especially explosive and/or high intensity activity (sprints, olympic lifts, near-max weightlifting) has important effects hormonally that cannot be replicated by any form of steady-state or 'aerobic' exercise or diet. High intensity activity drastically increases GH release (near-max squats stimulate GH release to well above baseline), testosterone levels, thyroid hormone sensitivity. It also decreases baseline cortisol and improves cortisol reactivity (i.e. healthier response to stress). It downregulates systemic sympathetic tone and improves blood pressure control substantially more than aerobic exercise does. It also improves the proportion of time spent in deeper stages of sleep (again important for the HPA axis functions that ONLY happen during deep sleep). True high-intensity weightlifting has not been studied very much unfortunately, but there is a trend for greater improvements in cognition in the elderly as well as younger populations, improvements in depression with an effect size similar to antidepressants, and a trend toward greater efficacy as an anti-anxiety treatment. In each of these areas, high-intensity weightlifting far outperforms traditional 'aerobic' work.
Oh, as an aside, high intensity weightlifting improves cardiovascular functioning by a similar margin to steady-state aerobic exercise (HIIT works better than both though).
I'm not even sure how to address your idea that muscle eventually becomes a fat container. Yes, BBers typically run to fat. This is because the form of hypertrophy they undergo is essentially big water balloons as opposed to dense rubber bands. And because they typically use artificial means to maintain their bulk (whether steroids, or excessive volume of weights, or glycogen storage increase or whatever), these means slowly become unstable over time.
But again, myofibrillar hypertrophy and fitness through high-intensity weight lifting is not about massive increases in body weight. In fact, I generally maintain that the size one would normally get to with this form of training is about the size of the average pre-agriculture Homo sapiens and slightly smaller than Homo heidelbergensis. The analogy here is a tiger in captivity versus one in the wild. One could argue that we should have more lean mass than we do due to our sedentary lifestyles and that the 5-20lbs extra puts them at 'normal'. There's nowhere for your huge containers of fat to go.
And to hit your final point, the science of weightlifting is quite complex. The old-time strongmen of the pre-steroid era actually had a far better intuitive grasp of it than most people realize, and they tended to be not so terribly huge (Hackenschmidt at 218 and 5'10' was one of the more massive of the turn of the century era strongmen--this roughly one standard dev outside of Homo heidelbergensis by weight and the same height, so nothing outlandish). What's done in gyms rarely bears any resemblance to the thousands-of-years-old tradition of weightlifting as practiced by ancient India, Greece, and the Celtic nations. It's usually BBer style training. High rep high volume isolation training. Even the gym bunnies are doing a variation of BBer style training for the most part. Functional weight training is typically big compound movements, near-max weights, low rep and low to moderate volume. The movements are often performed differently, with different energy systems, different tempos, and different, well, everything.
I've been a gym rat for years and I very rarely meet someone who is lifting using a strength and function-based protocol as opposed to a variation of a BBer template (even if they think they're going for strength and function--which to be fair, most are under the impression they are). You don't blame the hammer because someone's holding it by the head and trying to bang in a nail with the handle. Unfortunately, 95%+ of the people you see in the gym are doing just that.
p.s. I know I didn't touch on diet (which I do think is very important--I'm a Whole Foods/trader joe's/local grown/limit gluten/limit grains kind of guy). I'm tired and I just wrote a novel...
Yep! I remember those days. Absolutely disgusted with having to choose between sleeping and eating. Sleep would win most times. I'd wake up, 5:00 am with the most painful hunger pains I've ever experienced. #JustSayNotoSurgery
