Sunday, November 1, 2009

Muscle Will Turn to Fat?

Myth #2: If one gains a lot of muscle when young, it will all “turn to fat” when he or she is older.

The other day, I heard my housemate make the comment “I don't want to lift weights like Stevo, because when I'm older, all my muscle will turn to fat and I'll be more overweight then if I had never lifted.” My initial reaction was laughter, but then I had to humble myself and remember that I too once believed this. I do not know at what point this “fact” hit mainstream culture, but I hear it all the time. When I first began lifting in high school, I heard the same thing (and believed it for a while), but lifted anyway because I wanted what every hormonal teenage boy wants: big muscles to impress the ladies (oh how silly we all are at some point), and to be stronger than the guy next to him so he could win the next spontaneous wrestling match that will inevitably ignite during a gathering of guys (although this happens during every stage of a male's lifespan). As I'm now beyond high school (and soon college) and train for the pure rush of accomplishing something physical that was not possible to me at an earlier point in time, I better make sure that I'm not setting up myself for future obesity eh? Anyways, let's take a closer look:

What does basic science say? Well, muscle and fat cells are completely mutually exclusive of each other. At the physiological level, they are completely different. Muscle cells are elongated and contain multiple nuclei, whereas fat cells are globular-shaped and contain a single nucleus (you can look this up in any anatomy or exercise physiology textbook). Both types of cells may grow and shrink, but it is impossible for one to “morph” into the other. It is not physiologically possible for a muscle cell to turn into a fat cell, or for fat to convert to muscle. There are many countless other differences in the composition/function of these cells, but that is beyond the scope of this post and most of you would probably fall asleep reading about it.

So where does this myth stem from? Are there people that are oh-so-muscular in their youth, and then develop a much higher level of body fat when they're older? Certainly. Do many of you personally know (or at least know of) someone who used to possess a lot of muscle but now they look fat? I bet you do. Is this because his or her muscle actually morphed into fat? Not a chance.

What we commonly observe is a result of lifestyle change. Typically, (using a male in this example) a guy who lifts weights in high school and college does so because of a requirement by a sports team, or perhaps because he decides to do it as a hobby while he still has a lot of free time. As he enters his mid-twenties and pursues a career, he still exercises regularly, and receives enough guidance that he's able to put on a fair amount of muscle. This includes remaining in a caloric surplus (intaking more calories than he is expending, in order to gain size). However, as he gets older, an increasing amount of commitments find their way into his life. This may be an insatiable drive to climb the corporate ladder, thus requiring frequent late nights and early mornings at the office. Or perhaps he marries and has children, and needs to spend extra time providing for his wife and/or driving his kids to school/sports practice. As more and more obligations (positive or negative) consume him, he eventually foregoes exercise in order to make room for other things. He still eats a lot, because he has developed this habit when he was younger and was lifting consistently (and could just “work-off” any junk food he consumed). However, these food choices will probably become quite poor, as a fast-paced life will “demand” that he utilize fast food restaurants on-the-go. Over time, he skips more exercise sessions so that he can prioritize other activities, and continues to eat more not-so-gut-friendly-food as he finds himself frequently rushed and stressed.

See the trend? Over time, he exercises less, and doesn't reduce his calories to match his new activity level (which is next to none, excluding walking from his car to the office or house). Since he is no longer lifting weights (with the exception of maybe once every couple weeks), his body stops building muscle because he's no longer imposing that demand on himself (to be able to lift heavy stuff). His muscles get smaller because there is no stimulus for growth. He's still eating a lot of calorie-dense foods though, and those calories aren't going to be used in muscle building. Since he's now intaking way more calories than he's expending throughout the day, those excess calories are stored as fat. Over time, our muscular college boy has gradually morphed into an overweight business man.

And the conclusion people draw? “Ohh, yeah, I remember he used to be quite fit-looking. He must be fat now because he put on all that muscle when he was younger, and now that he has aged, his body is converting it to fat.”

Riiigghht. His muscle did not “melt into fat.” He lost muscle mass because he wasn't exercising, and he gained fat because he didn't adjust his dietary intake to match his lower caloric expenditure throughout each day.

So what can we take from all this? You need not avoid lifting weights as a youth in fear of that muscle turning to fat. Just be conscious of your lifestyle as you age. Are you frequently stressed? This will increase cortisol (a hormone leading to fat storage as well as a number of other maladies) levels, so you either need to remove that stressor from your life, or find some way to combat the stress (try taking a walk outside, spending time with a loved one, reading, exercising, etc). Are you as active as you were in middle school, high school, college, or whatever your most recent stage of life was? If not, then you need to adjust (down) your daily caloric intake accordingly. Build the habit of exercising for the right reasons while young, and you'll be more likely to make it a regular part of your schedule no matter how old you are or what time commitments may be pressing. Even if it's a workout out twice a week for 45 minutes per session, you'd be surprised at how much it will help your quality of life.


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