Tuesday, December 11, 2007

Do You Really Have A Slow Metabolism?

I think one of the biggest myths about weight loss is that overweight/obese folks have a slow metabolism. Hell, I use to claim this one all the time back in the day. It simply made sense to me. The majority of my family is overweight, so I just accepted the fact that I was genetically coded to be fat and cursed with a tortoise-like metabolism. Much like the whale in the comic strip, I just didn't fully understand why I couldn't lose weight.

Fellas, I know that you have read books, articles, and even other blog posts about how to speed up your slow metabolism for weight loss, blah, blah, blah. There's so much confusion out there simply because most big boys simply take somebody else's word for how to lose weight. Many of us simply want to be told what to eat and how to exercise without any active role on our part. Well, it's time to ditch the "easy" way of thinking and passively sitting by while your girth increases.

Well, today is the day that you are going to eliminate one of the most repeated weight loss myths from your bag-o-weight loss tricks. First, metabolism is a word that is thrown around as if most people really understand what it is. Wikipedia, one of my favorite sites, defines metabolism as the set of chemical reactions that occur in living organisms in order to maintain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. You can read the rest of the definition and sub-categories here, but for purposes on this post, the first two sentences will be more than enough.

So, another way of looking at your body's metabolism is that it is the sum total of all of the daily activities that your body carries out on all levels (e.g., cellular, etc.). Usually when one talks about revving up your metabolism, they focus mainly on affecting one part of the Total Daily Energy Expenditure (TDEE) equation. It's important that you understand what makes up your TDEE because it will make it abundantly clear that the notion of fat guys having a slow metabolism is a big fat lie!

OK, here's the equation: TDEE = Resting Metabolic Rate (RMR) + Thermic Effect of Food (TEF) + Voluntary Physical Activity (PAL). OK, your RMR is determined by your age, gender, height, and current weight. This accounts for 75% of your total TDEE and is comprised of all the bodily processes that need to be fueled; this, of course, includes fueling ALL organs such as the brain, kidney, lungs, liver, heart and kidneys to name a few. Also included in RMR are the energy it takes to power you skeletal muscles. Next, it does require energy for the body to process the food that we eat; however, TEF only accounts for 6-10% of your TDEE, so it's not really that significant of a factor. Please remember this the next time you hear someone telling you that you burn a lot of calories digesting your food; it's simply not true.

So, we have roughly 80 - 85% of your TDEE that you have no direct control over. What you can control is the 15-20% that's generated by your PAL, which is usually broken down into structured physical activity, such as following a workout routine, and unstructured physical activity, such as taking the steps instead of the elevator or parking farther away from the front door of the mall.

Alright, enough with the scientific mumbo-jumbo, let's start making sense out of all this. OK, the man in the street believes that he is overweight because he has a slow metabolism. The logic usually goes like this: fat folks must have a slow metabolism because of the extra weight, lack of exercise, and overeating. Oh, and not to mention that many thin people (who have a "fast" metabolism) can eat whatever they want and not gain weight. Well, I hate to break this news to you guys, but it is impossible for a thin person to have a faster, or should I say higher TDEE. It's really simple; your body requires more energy to move around a larger body, but that's only half the story.

Remember that your RMR represents all of the bodily processes that happens on a daily basis, except the little energy required to digest your food (i.e., TEF). The organs I named above represent 60-80% of your total RMR! This means that while skeletal muscles represent 30-50% of total bodyweight, they only represent 20-25% of your RMR. Organs, especially the brain, require many more calories per gram of weight than muscles.

You still with me fellas? Cool.

Now, let's think about what we've gone over to see if fat folks do actually have a slow metabolism. When you gain weight, you don't just gain fat. You also gain lean body mass (i.e., bones, tissues, organs, etc.). The body is all about adaptation. As you gain weight, your body also creates more muscle tissue to help move the heavier body around. The heart and most of the other organs also grow, which only makes sense. Do you really think that the heart in a 180lb. man is the same size as one in a 350lb. man? Of course not; that's like putting a 4 cylinder engine in a Ford Excursion. Organs have to increase in size to accommodate carrying out their processes for the new heavier body. This is why larger bodies require more calories, and, therefore, a faster metabolism.

Well, what affects RMR? I'm glad you asked:

  • the number of calories consumed a day
  • changes in bodyweight (especially body fat %)
  • when daily calories drop below 1200, big drops in RMR occurs
  • ECA Stack (ephedera, caffiene, aspirin)
So guys, if you can't see your feet while standing or you use your navel to line up the toilet when you take a leak, trust me on this one: you don't have a slow metabolism and are not condemned to live the rest of your life being as big as a whale.


Pete said...

You just gotta love facts! Good post.

Lindsey said...

There is an inspiring, new book called Hungry: Lessons Learned on the Journey from Fat to Thin. The author shares his incredible journey both up and down the scale and blends his personal story with weight loss advice, laughter, and inspiration. I recommend it for anyone dealing with a food and weight problem.

Charles said...

I found a great blog article about easy ways to increase your metabolism to burn fat. http://weightcontrolinfo.com/2008/07/02/7-ways-to-boost-metabolism-fast-and-slash-your-body-fat/