Is there a maximum limit to the amount of muscle I can naturally (without steroids) add to my body? If so, about how much would that be for an “average” man of “average” build?
There is always going to be a maximum limit, whether you are natural or enhanced (we normally say enhanced and not steroids, because things such as insulin, IGF-1 are what we call peptide hormones and not anabolic steroids, yet they are used to push the body beyond its natural capabilities). Now, lets talk natural. There are a couple of things you need to bring to the equation to find out what your so called ceiling is when it comes to building lean muscle tissue.
The first is your genetics, now, what I mean by that is, what type of body type are you? Endomorph, ectomorph or a mesomorph? This is something you cannot really change, you can be a hybrid of two, but this is the criteria that all of us fit into. So, are you a naturally lean guy? Fast metabolism? Or do you feel that who are more on the softer side, and tend to hold more fat? Now if you are a mesomorph, that you ability to build muscle is a lot quicker, but judging from your question, I am assuming you are either ectomorph or endomorph, please correct me if I am wrong...because a mesomorph will describe himself or herself as athletic build.
The second thing, to then have the correct nutritional plan according to your body type. Everyone can get into shape, and look and feel good, but is understanding your body type first, then making sure the right compatible nutrition program goes with it. I train numerous clients, and the first question I ask them is not how much they lift, but what they cook and eat. Nutrition is 80% of what you can control, genetics you cannot control, but of the 100% you can, 80% is nutrition....so the first thing is to get your kitchen in order. Getting the nutrition right should always be the first step, because training is going to be about one hour of the day, nutrition is an all day thing. I have had starters just focus a few weeks on getting their food intake right, then focus on lifting in the gym.
Finally, the remaining 20% is your training. If you are not looking to achieve the absolute pinnacle of what your natural limits are, i.e a natural bodybuilding contest, but still want to get to a point where what you gain is sustainable and balanced with the rest of your life (because reaching your absolute limit, with or without enhancements is very timing consuming, and quite often not socially acceptable to that personal and realistically unsustainable for long periods) - then focus the foundation exercises of squat, dead lift, and bench as pillars and then build a routine around them.
This again leads me to another question, how much time do you have to go to the gym? The more time you have, the more options you have in targeting specific muscles. Compound movements to not only build strength, and size, but to also functional strength throughout the body which increases bone density, and provides longevity. Isolation movements are ideal for shaping the muscle, but they do not produce the natural anabolic environment in your body that the big compound movements do. Since you are natural, you need to stimulate production of testosterone, growth hormone...this takes me back to your nutrition point. The foods you eat should help your synthesize natural testosterone, peptide hormones, and T3 from your thyroid.
You can achieve many great things, but sometimes to go forward you need to take a step back and evaluate where you are. Is your nutrition as clean as it should be? If it is then are you using things such as carb cycling, nutritional partitioning, intermittent fasting, ketosis? The best thing I would advise is making a food diary and note down everything you eat all week, everything, all snacks, and see exactly what you are consuming, it can be an eye opener, it was for me. That will also then allow you to start substituting bad foods with good ones.
I hope this info helps you out.
