According to figures tallied by researchers from the London School of Hygiene & Tropical Medicine (LSHTM), the average weight of an adult human being on this planet at present is 136.5 lbs. The average weight of adult humans in North America, however, is 177.5 lbs.

This 41-lb. difference creates another great weight-related discrepancy: While North America is home to only 6 percent of the world's population, those people possess 34 percent of the world's total body weight.Conversely, a continent considered overpopulated because it's home to 61 percent of all humans, Asia, accounts for only 13 percent of the world's total body weight.Such statistics were part of an article published in June online by BMC Public Health in an attempt to show that there's an element to overpopulation that many people never consider: body mass. In fact, the extra food required to keep the world's overweight and obese people overweight and obese could feed another half billion average-weight people.In a release to the press, Ian Roberts, Professor of Epidemiology & Public Health at LSHTM and spokesman for the research team, said: "Everyone accepts that population growth threatens global environmental sustainability. Our study shows that population fatness is also a major threat."While Roberts makes a valid point, I believe the research supports something else: that the worldwide obesity epidemic results more from poor lifestyle choices than poor genetics.Consider these statistics I used to suggest lifestyle trumps genetics in a nutrition class I taught a few years ago. At that time, 22 percent of adults born in the U.S. were obese not overweight! yet only 8 percent of adult immigrants in the U.S. less than one year were so. But guess what happened over the next 15 years?Enough of those immigrants adopted the poor-eating and lack-of-exercise habits prevalent in their new country so that now 19 percent were now obese, an increase of 237.5 percent.Their genetics didn't change in 15 years. But their lifestyles surely did.And while those numbers I cite may now be outdated, newer research insinuates the same.This summer, the American Heart Association's journal Circulation reported that even if you stay in a foreign country and start a habit seen as undeniably American, consuming fast food, you increase your risk of diabetes and heart disease. University of Minnesota School of Public Health researchers analyzed data compiled on 52,000 residents of Singapore who started eating a less traditional and more U.S.-style diet 16 years ago.Over the course of the study, those who ate more than three fast food items a week were nearly 80 percent more likely to die from heart disease than those who ate none.Subjects who ate fast food twice or more a week increased their risk of developing diabetes by 27 percent.More proof that lifestyle trumps genes comes from research performed at the Department of Nutrition at Harvard School of Public Health and first presented this spring at an American Heart Association Meeting. In this study, researchers found that those subjects who had a genetic predisposition toward obesity were not doomed.What lead author D. Qibin Qi, a postdoctoral fellow called, "a brisk one-hour daily walk" reduced the genetic influences determined by changes in body mass index (BMI) by 50 percent.Similarly, those who spent four or more hours a day watching television, a very sedentary activity, were 50 percent more likely to be obese.The emerging field of epigenetics shows how your food choices influence genetics. What research done at the University of Alabama at Birmingham has found is that eating certain foods can actually suppresses certain genes from "turning on" or expressing themselves even the genes that create certain cancers.And UAB researchers believe they know why. A number of compounds in vegetables repress gene aberrations that create diseases. When they reviewed similar studies done internationally, they found the same.The result was an article published in 2011 in the journal Clinical Epigenetics that declared certain foods cabbage, cauliflower, kale, Brussels sprouts, soy beans, fava beans, grapes, green tea, and broccoli can prevent certain diseases seen as genetic. UAB researchers hypothesized, however, there are probably dozens more.While it's quite possible that not many or even none! of the nine aforementioned foods are your favorites, research like this should provide the impetus for you to experiment with these foods in your standard fare.Fava beans, cabbage, and grapes, for instance, can be added to salads, kale can be steamed and eaten like spinach, and many meat substitutes, like Morning Star and Boca Burger products, feature soy. Brussels sprouts, broccoli, and cauliflower are traditionally steamed, but many people prefer roasting them with some spices and a bit of olive oil.