Note: This is for males. Females can pretty much half this due to their lower muscle gaining potential.
A trainee can be considered a beginner for approximately the first 10kg of muscle mass gained, assuming he starts from his normal weight (again, females can approximately half this for a reasonable estimate, and of course this is a very vague figure given to provide some amount of context). This should take somewhere in the region of 12-18 months of good gym programming and eating on average, but of course could take more or less time. The intermediate stage lasts as long as a piece of string unfortunately, and the advanced stage is even harder to define, but the point here should be quite self-evident.
A typical 75kg male, assuming he has never touched a weight in his life, can hope to gain at best (assuming great genetics, eating and training) 1.2kgs of muscle per month in his first year, which is around 300g per week. After that the number drops to around 750g-1kg per month for a while before trailing off into amounts which are difficult to even measure.
A typical 60kg female can hope to maybe gain at best 600g or so muscle per month, or 150g per week, dropping to 150g per month or so after that.
Your rate of weight gain, therefore, should be pretty slow.
It’s a good idea for males to aim for a gain of about 0.25-0.5% bodyweight gain per week (or 1-2% per month) which will more than likely translate to something along the lines of a 5-10% increase in calories, or 200-400kcals per day for most.
A female could go for around 0.15-0.3% of bodyweight gained per week (or roughly 1% per month), meaning a 150-300kcal surplus per day, for most.
As we’d hope is obvious, you may need to adjust these figures depending on how you progress because as we said, you might experience resistance. You’ll note that this rate of gain is a little higher than the possible muscle gain figure but that is because you will gain some additional water within your muscle cells as an adaptation to training and you will probably gain some fat alongside that, too. A targeted weight gain period should last around 3 months at best (4 in some very rare cases) before you consider a leaning out phase to reduce bodyfat back to levels you are happy with and that are healthy. If after this time, you haven’t gained all that much weight, consider eating a little more and going for a few months longer.
The rate you choose should be dictated almost exclusively by how comfortable you are with gaining a little extra bodyfat. Assuming you are going to follow the guidelines to gain weight slowly and only for given periods of time you are unlikely to adversely affect your health by gaining weight at the higher end of what we have mentioned here, but you might start to hang over your jeans a little more. The happier you are with some fat gain, the faster you should gain weight (within these guidelines) as it can potentially increase your muscle mass accruement, but please note that overeating for the sake of it and gaining 3-4kg per month or more only results in extra fat gain which you’ll have to deal with at some point in your next dieting phase. If that’s something you’re comfortable with, of course, be our guest – there’s no moral judgement to be made here.
We know, though, that the vast majority of people are looking to reduce their weight (or at least their bodyfat) and as such we will now return to the other side of the coin – facilitating weight loss.