Not sure I would characterize obese people as ' lazy ' - I think that is just another myth / stereotype.
Do you think would also apply to other forms of over consumption - like ' over-drinking ' - might also stem from simply ' learning ' bad habits ?
If alcoholism is alleged to run in families and therefore may have a strong hereditary component to it - I wonder if bad eating habits do as well ?
Well, that's just it: we've primarily been focused on the physical aspects of genetically influenced obesity, but don't forget that there's a strong
psychological and neurological aspect to it as well: terming the difficulty that some people have with sticking with a diet or exercise routine can have as much to do with actual neurologically induced issues as it can have to do with anything else...again, this doesn't mean that these issues cant be overcome with effort, but think about this: we accept that alcoholism is strongly affected by heredity, that depression, anxiety, attention-deficit, etc, are all neurologic disorders, but then we turn around and claim that obese people that can't stick to a diet, basically doing what we are
genetically programmed to do in order to survive (i.e. consuming in times of prosperity in order to survive in times of famine: 60 years of McDonalds and easily available food isn't long enough to alter our genetic programming), are in fact "lazy" and should be shunned. The fact is, 5000 years ago, the body-type that we covet, the lean and slender individual, would be a sign of
poor health because they would be less likely to be able to survive during stress and starvation. These individuals are following a genetically programmed plan that had been successful in keeping the human species alive for hundreds of thousands of years. Our genetic purpose is to live long enough to give birth to offspring and to live long enough to raise them until they are capable of independent living, which is basically 30 years or so, and for the majority of our existence, that is exactly what we did. Now with improvements in medicine and standards of living (including food availability, shelter, cleanliness, etc, etc), we can live 2-3x as long, if not more. What helps us early in life ends up killing us later on, but this is "genetically" unimportant. Modern lifestyles work against our biology, which includes the genetic mandate to eat, eat, eat. This is the root of the problem, not some abstract concept of "laziness."
As far as how much does metabolic type vary, the truth is that most studies show that it's not much from person to person, if I recall...however, it's also important to look at subject populations, too: syudies also show differences in the way that obese individuals actually utilize the calories that they consume vs. lean individuals, even when taking into account activity levels or influences of obesity itself (i.e. type II diabetes).
Early reports of "50 calories/day" additional BMR per pound of muscle estimates have been lowered considerably, to around 7-12 kcals/pound of muscle per day. Meaning if I start working out today and put on an additional 20 pounds of muscle in a year, I have only increased my BMR by around 150-200 calories/day, which is barely significant (that's roughly one extra banana a day...of course, energy requirements needed to sustain the work levels that i will need to build that muscle will be greater too, which is why active people need to eat substantially more). However, the
sum total of genetic factors (not just BMR due to muscle type, distribution, and amount but actual chemical/hormonal factors, neuromuscular efficiency, psychological brain chemistry, blah, blah, blah) might make this more significant, too.
Like G said, we don't know to what effect any of this will play on any specific individual; however, like I was trying to say, by knowing that these are
real factors and not just laziness, we are able to not only better understand
why an individual might be having difficulty with their efforts but to be able to better tailor our own efforts in helping them through their difficulties. It's easy to label someone as being lazy. It's also counter-productive and won't help
anyone that is attempting an honest lifestyle change having
real issues that go beyond a simple issue of motivation.
