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Genetic Factors:

Numerous scientific studies have established that your genes play an important role in your tendency to gain weight.

• The body weight of adopted children shows no correlation with the body weight of their adoptive parents, who feed them and teach them how to eat. Their weight does have an 80% correlation with their genetic parents, whom they have never met.
  

• Identical twins, with the same genes, show a much higher similarity of body weights than do fraternal twins, who have different genes.

• Certain groups of people, such as the Pima Indian tribe in Arizona, have a very high incidence of severe obesity. They also have significantly higher rates of diabetes and heart disease than other ethnic groups.

We probably have a number of genes directly related to weight. Just as some genes determine eye color or height, others affect our appetite, our ability to feel full or satisfied, our metabolism, our fat-storing ability, and even our natural activity levels.

In fact, the ability to store fat, a portable energy source, can undoubtedly be viewed as a survival trait. One that has been selected out over millions of years. It allowed our cave-dwelling ancestors to survive famines and those long winters in caves. Proof of this is found in their primitive art.

But just in the last 100 years, our evolution has drastically outpaced our biologic evolution and what was once a survival trait is now totally maladaptive, and has actually become a chronic, progressive, and ultimately fatal disease process.

Environmental Factors:

Environmental and genetic factors are obviously closely intertwined. If you have a genetic predisposition toward obesity, then the modern American lifestyle and environment may make controlling weight more difficult.

Fast food, long days sitting at a desk, and suburban neighborhoods that require cars all magnify hereditary factors such as metabolism and efficient fat storage.

For those suffering from morbid obesity, anything less than a total change in environment usually results in failure to reach and maintain a healthy body weight.

Additional Contributors:

• Genetic and environmental factors
  
• The Pima paradox
• Metabolism
  
• Eating disorders and medical conditions

Return to the Causes of Obesity Web page

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