How Having A lot of Extra Body Fat Affects Muscle Growth
Current available science has indicated that high levels of bodyfat (what qualifies as “high” I’ll get to in a moment) alters the body’s insulin sensitivity to the degree that it will actually impede or limit muscle growth.
In other words, there is a cap on your “gains”.
There comes a point where carrying too much bodyfat reduces what’s known as peripheral insulin sensitivity. This is simply insulin resistance in its most common form. It refers to how readily body cells in your periphery tissue (muscle and fat) can absorb glucose.
Science aside, I have frequently seen this with my own clients as well- there comes a point in any mass/muscle gain endeavor where the accumulation of too much body fat simply results in the accumulation of too much body fat. It’s why I always strive to keep bodyfat gains minimal. If you want to gain muscle you shouldn’t allow your bodyfat to get too high because if so, it’ll actually hamper your ability for maximal muscle growth. You’re better off eating as much as you possibly can while keeping bodyfat within a healthy/low range.
What is too “high” when it comes to bodyfat?
As always, individual factors come into play, but in general, I like to see most men to keep bodyfat around or under 15-16%. If your bodyfat is higher than that it’s a good idea to drop some fat first, then mass. And for women, anything higher than 24-25% tends to result in just more fat gain. You also want to watch your physique, visually. You can tell when you’re accumulating adipose tissue, and if it appears you’re packing on excess fat it’s best to slow adding in any more calories.
I also should mention, however, that the there are also problems with being too lean when it comes to muscle growth. Carrying extremely low levels of bodyfat for an extended period of time hampers muscle gain and also increases your susceptibility to muscle loss. In short- it will eventually render you skinny soft due to muscle wasting. For men, the cutoff seems to be under 5% fat and for women under 12% or so. Basically, if you want to add quality muscle as a male being somewhere between 10-16% is a good idea and for women somewhere between 15-20%.
I know a lot of people have argued with me on this middle ground “stay lean but not TOO lean” approach, but my personal experience as an athlete, my experience as a coach, AND some science has clearly indicated that keeping your bodyfat under control, at all times is incredibly important when it comes to muscle growth and retention.
When I was younger I used to allow my weight and bodyfat to really leap when I wasn’t in prep, and trust me when I say very little muscle was ever added at the expense of a lot of fat. On the flip side, since keeping myself leaner and emphasizing food quality at ALL times, I’ve been able to make great gains in lean muscle (given that I’m a natural athlete) while only accumulating a few extra percentage points in bodyfat.