We’re good at not starving, but not so good at being sedentary, although we try hard.
From Live Science (emphases mine):
Researchers from the University of Maryland School of Medicine in Baltimore studying Old Order Amish – the Amish sect that shuns most modern conveniences – found that middle-aged Amish adults with the so-called “obesity gene” could beat their genetic destiny and maintain and healthy weight through pure physical activity. You don’t have to raise a barn or harrow a field with a horse and hitch to stay thin. But you do need to play hard, the study found, burning about a thousand calories a day through vigorous exercise such as rowing or running for an hour.
Genetics is not destiny. Your genes are the plan. Ask any designer or architect or engineer what happens to even the best-made plans.
It’s no illusion that some people pack on the pounds more easily than others despite a similar diet and level of physical exertion. In recent years researchers have found numerous genes contributing to weight gain and eating behavior. Carriers of a mutations in one gene, called the fat mass and obesity associated (FTO) gene, present in nearly half of European stock, are about 30 to 60 percent more likely to be fat. The University of Maryland researchers decided to examine the FTO gene in the homogenous Amish community. They found that, as with others of European descent, this gene did contribute to being overweight in the Amish community. But the excess weight was seen only in those individuals with low physical activity scores, mostly women performing house chores. The genes had absolutely no effect for those burning an additional 900 calories through several hours of moderately intensive physical exercise – such as farming like it was 1708.
Have you ever seen an avid runner, or for that matter, growing teenager eat and eat (and eat)? Calorie intake is just one side of the equation. How many thousands of calories does Michael Phelps need to eat to not lose weight?
I also need to point out that, while yes, the Amish enjoy eating all of the pig, as does most traditional cuisine, they are also not guzzling sodas and corn sweeteners the way that most modern Americans do. Calorically, they’re probably consuming about as much as we do. The source of those calories is nutritionally superior to our diets, and for the most part, they burn up all of those calories by not being sedentary.
Physical activity even trumped diet. The Amish enjoy eating every part of the pig with gusto, along with gravy, potatoes and pies. And they get away with it. An earlier study found that Amish men walk 18,000 steps per day, compared to about 18 steps from house to car to office that many Americans get. Life’s just different without electricity and running water. The Amish do have an advantage in that they burn more calories through exercise throughout their entire lives, and they are in effect nurturing nature. Not gaining access weight is the easiest way to maintain a healthy weight. Yet at a very basic level the University of Maryland study reveals what is perhaps obvious to many: Population-wide obesity is a modern phenomenon. We carry the same genes as our ancestors did, but lifestyle changes have brought on the obesity epidemic.