Obesity and the modern man

Given today's environment, it is surprising that there are still thin people around.When I was at Raging Waters water park this weekend, I was reminded yet again of the obesity epidemic in the U.S. Almost everyone there (myself included) was at the very least overweight.

The origins of this epidemic are pretty easy to spot-- lots of food and less opportunity for exercise. And yet, not everyone in the U.S. is overweight. So why is one person fat and the next thin?

One big reason is genetics. A number of twin, family and adoption studies have found that somewhere between 45-60% of body mass index (BMI) comes from the genes we inherit. In other words, some people are more likely to be sucked into a Super-Sized meal because of their genes.

So how might genes affect someone’s chances of succumbing to the mountain of food now available? Lots of ways.

Some people burn energy more slowly than other people. These folks need to eat less to maintain their weight. Not an easy thing to do!

Some people take longer to realize they are full. Others get hungrier more quickly after eating. Still others need more sweets and fat to get enjoyment from their food.

The last example was <a href="http://psycnet.apa.org/index.cfm?fa=main.showContent&id=2007-13974-007&view=fulltext&format=html
">addressed by a study last year. One of the reasons people eat is that they get a hit of dopamine when they do. The dopamine makes us feel good and once we get it, we feel less inclined to keep eating.

The study found that people with a certain version of the DRD2 gene needed more food to get enough dopamine to stop eating. So they ate more on average.

There are more and more studies finding gene variations just like this one. Finding these gene variations might be useful in creating new medicines to help people eat less by decreasing hunger, burning calories faster, etc.

Knowing about these gene variations might also help doctors identify who is at a greater risk for obesity. These folks can get early help in maintaining their optimal body weight.

Now none of this is an excuse for getting fat (although I wish it was). For the most part, genes that affect our BMI make maintaining a healthy weight harder, not impossible.

But what it also means is that the thin should be a bit nicer to the overweight. Recognize that it might be easier for the thin person to not overeat.

This is not to take away from the thin person's accomplishment. In a world awash in high calorie foods and with work and play involving a lot of sitting, it takes will power not to become overweight. Just remember that it is easier for some people to be thin.

http://www.cdc.gov/nccdphp/dnpa/obesity/trend/maps/index.htm

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