The Genetics of Metabolism, Appetite, and Taste
Food makes us fat. That’s a harsh reality that exercise has difficulty overcoming. It takes a great deal of exercise to overcome slow metabolism combined with an oversized appetite. Our metabolism and appetite are partly controlled by our genetic make-up. One recent twin study found that about 50% of weight differences in male twins could be attributed to genes. (IOL Medical, June 10, 2005)
The chemical basis of obesity is known to some extent. Some overweight people have a defective melanocortin-4 receptor, which means their brains receive messages from leptin, the appetite-blunting hormone, poorly or not at all. Other overweight people, though very few, have a defective gene for leptin.
Released by the body’s fat cells, leptin plays a major role in obesity in any case, Annette Schurmann, a pharmacologist at the German Institute of Nutrition Research in Potsdam said. The more fat cells a person has, the more leptin the cells release. But the body develops resistance to the excessive amounts of the hormone, and does not react normally to it.
“For example, the hormone doesn’t bind to the receptor as well, or the message is passed on in a weakened form,” she said. So the urge to eat is not curbed - a vicious circle that is hard to break.
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Genes not only affect metabolism and appetite, but also taste. People with a certain gene type, for instance, have an aversion to cabbage and spinach.
As Professor Wolfgang Meyerhof from the Institute of Nutrition Research discovered, such people are especially sensitive to the bitter constituents of those foods.
On the other hand, people who do not taste the bitterness at all, tend to eat more fat and be overweight.
I wouldn’t be surprised if I had defective melanocortin-4 receptors. My leptin levels are probably out of whack too. And it’s highly possible that my very slim husband, who disdains many kinds of vegetables, has passed those genes to our toddler son. I don’t know whether to be happy or sad.
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POSTED IN: General Genetics and Health
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2 opinions for The Genetics of Metabolism, Appetite, and Taste
river2sea72
Jun 13, 2005 at 8:26 am
Oh, I believe that completely. My dad and I have similar metabolisms and are both skinny, no matter what we eat. My hubby, on the other hand, has his dad’s metabolism, and even theough he and I eat similarly healthy diets, he is always on the heavy side.
Lei
Jun 14, 2005 at 10:45 pm
river2sea72 - Yes, some of us are just doomed. ;) But, seriously, I came to terms with my less than skinny figure long ago and am just trying to maintain a healthy weight. If I had tried to get down to supermodel form, I’m sure I would have spent a lot of time stressing and being unhappy.
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