A few weeks back I got an email off a gent who was looking to change his body composition a bit. He’d done a bit of training and seemed to know what he was talking about, so got specific with numbers. The goal was;
To go from 77kg and 15% body fat to 80kg and 10% body fat. He wanted to know how long that’d take.
So let ‘s look at the numbers;
77kg @ 15% = approx. 66kg lean body mass / 11kg fat mass
80kg @ 10% = approx. 72.5kg lean body mass / 7.5kg fat mass
So your question essentially becomes – how can someone lose 3.5kg of fat and gain 6.5kg of muscle.
For most intermediate lifters, the ACTUAL amount of muscle you can expect to gain each month is around .25-.5kg. So over a year you might gain 3-6kg if you do everything perfectly and nail the correct calorie surplus.
Dropping 3.5kg of fat is easy peasey with a bit of discipline and is easily doable without anything crazy over 8-12 weeks.
So, assuming the person is a natural athlete with at least average genetics you’d be looking at at a time horizon of 2-3 years to do that.
When it comes to “what training program would you put someone on” for that… It’s not REALLY about the program. It’s about the long-term development of all physical qualities so the style of training would wave and change based off that.
Now you’ll see other trainers claim faster results, better ways blah blah blah but for the most part they’re either lying, making it up or just don’t understand what they’re talking about.
It’s very easy to “accidentally” get BF% readings wrong with a calipers to trick a client. If you wanted to remove the trainer from the equation and be a cold analyst, get a dexa scan before and after.
And once again, I direct you to go and read Lyle McDonalds thoughts on the topic here: https://www.bodyrecomposition.com/muscle-gain/whats-my-genetic-muscular-potential.html/