Expert: Florence M Rollwagen - 4/26/2009

Question
I am 67yrs old and have always been very skinny (~118lbs 5'10"). When I tell people "I could eat nothing but banana splits all day long and never gain an ounce...all that would happen is that my face would break out in zits.", they laugh & say how lucky I am & that my metabolism must be very high. I disagree and believe the word metabolism is used haphazardly by the general public. Higher than typical metabolism would imply one or more higher than typical vital signs (e.g. core temp, heart rate, blood pressure, respiratory rate). Mine are all below average. I believe that instead I have inherited an inability to store fat efficiently probably from my dad who also could not gain weight; like most people, my mother could gain weight easily. Thanks in advance for your thoughts on this subject and any references you might have.

Answer
Hi John:  Thanks for your question.

You’re in luck!  Recent scientific discoveries have shown that the ratio of brown fat to white fat can alter metabolism.  Brown fat is found in infants, its higher metabolic rate is used to generate heat in this population which is unable to shiver to keep warm.

Brown fat metabolizes at a higher rate, so having more of it tends to increase metabolism.  It’s unknown whether naturally thin people (such as yourself) have more brown fat, but it’s a good guess.

Here’s more information on brown fat:
http://www.nytimes.com/2009/04/09/health/research/09fat.html?ref=research
http://www.sciencedaily.com/releases/2009/04/090416102241.htm
http://www.sciencedaily.com/releases/2008/05/080514171819.htm
http://www.sciencedaily.com/releases/2008/08/080820162852.htm

You might also consider that you may eat less than you think and exercise more than you think.  Keeping a log of these activities might help to explain your (lucky!) situation.

Hope this helps.  Write back if you have more questions.

FM Rollwagen, PhD