May 6, 2013 I beg to differ on "building any mass at all" - frankly I got my biceps rolling when I was moving books for a library move for my physics group in college. Esp when you get started, starting from "nothing" in terms of weight training, it is not all that hard to get some amount of lean muscle mass going. The "Bulky" mass and the "man look" is what is hard to accomplish. Additionally when we talk about "building mass" it can mean a body recomposition where you're equivalently dropping bodyfat - not just getting ****ing big. I think its important for women to understand that "building lean muscle mass" is not a bad thing. It doesn't immediately mean you are going to "get big" but rather you are optimizing your body composition. But second to that is the fact that your body will respond to the stimuli that you give it. If you want to grow, you need to eat. But at the same time, more simply, if you want your body to function optimally, you need to eat. What you do once you've fueled is up to you & your goals. If you want to be a distance runner, you're probably not going to be looking to lift weights and opt to use the fuel you've consumed for running. If you want to "tone up" you're really saying you want to build lean muscle mass and drop bodyfat - THAT means you need to do some resistance training. Its always a balance between fueling for your goals and expending energy as appropriate to your goals. The only caveat to the whole above conversation is going to be the individual factor of what is your natural metabolism (which can be a subset of what is your natural balance of estro / test / progsterone). If you tend to he very lean, then you are most likely a hard gainer and will need to eat more to fuel muscle growth. For a very lean person, this can be seen more as a move from "skinny fat" to more filled out but still not appearing very muscular -it is still back to body composition. So to my primary point - just as it is a misconception that women can "get big" from doing any amount of weight lifting, it is also a misconception that it is impossible to gain lean mass. It might not always be visually obvious, but when you measure via photos, how your clothes fit, and skinfold or other means of reasonably accurate bodyfat measurement, you will see that there is body comp change underway.