When I first started dating Brian, for example, I was amazed as to how much he could eat and remained as thin as could be. "Lucky him", I'd say to myself as I tried to refrain from eating that second brownie.
After a few years, this darn voice in the back of my head - you know, the one that uses reason - keeps telling me that perhaps Brian's body type has a whole lot more to do with his perpetual motion than anything he's got going in his genes. And it turns out that reason prevails again.
The following summary appeared in a Runner's World blog:
Don't Read This If You Want To Blame Your Metabolic Rate For The Extra Pounds
Many overweight people blame their resting metabolic rate for their problems, insisting they just weren't meant to be lean. Those folks won't like this new report from the well known Pennington Biomedical Research Center. The researchers followed 10 lean and 10 obese women over 14 days, measuring both their resting metabolic rates (RMR) and their total daily energy expenditure (RMR plus movement calories). Result: There was little difference in RMRs between the lean and obese women. However the obese sat 2.5 hours more per day than the lean, stood 2 hours less, and moved about half as much. The difference amounted to about 300 calories per day. And that, of course, is equivalent to 31 pounds a year.
Source: Obesity. http://www.ncbi.nlm.nih.gov/pubmed/18223609