I turned 47 this past Jan. Lifting since I was 32. I did it at first to shed lots of fat. 239lbs @5'11". I was my best around 42 and 43 years. 185lb..14% body fat. I know its not great by most standards however where I was was not an option. I slowed down over the last two years and gave back some muscle and energy. So I started again and just finished my measurements yesterday @ 180lbs and 16% after working for nine months. I do have that momentum feeling again that you sense when your workouts have been superior, tendon pain is very noticeable now.I did all the supls during the first few years.. if it was new... i bought it. I did figure out the protein equation for me. I think its much more important as you age. You have to replace the carbs with something of value. The slower metabolism requires you to change eating habits... and time requirements of being further along in life does not always allow for 5 or 6 quality workouts a week.
Now, we are looking to get to 190 @ 14 or 13% ( woo woo) body fat! The good thing about this hobby is that each success is unique and huge in lifting to the individual... with no finish line. It takes committment.
I'm 44, and have been lifting with various degrees of intensity for about 5 years now. I do not have the pre-disposition to gain a lot of muscle, but my body has been changing for the better. I've been doing a lot more cardio lately to lose the weight I gained around my waist from too many protien shakes.