Many men and women who have trouble controlling their weight often attribute their situation to "genetics." The link between heredity and the ability of a person to lose pounds or simply to maintain a healthy weight is well known. This fact may lead many individuals to ask whether they are genetically predisposed to weight problems. Thanks to modern science, however, this question can be answered.

The Evidence

Empirical evidence, which is obtained through observation, has proven the genetic connection to weight in humans. Some of these studies have used comparisons in weight patterns between identical twins and those of adopted children who had similar lifestyles. Research conducted in recent decades indicates that up to 70 percent of the cases of obesity in the U.S. are at least somewhat related to inherited factors.

In some cases, the genetic link to obesity may be direct. Certain chromosomal defects can both lead to an overweight condition and prevent the person from losing that weight. Although a defect in a single gene can directly result in morbid obesity, this is thought to be a factor in only a small number of cases. Normally, hundreds of different genes are involved, causing the offspring to be indirectly susceptible to obesity and resistant to weight loss. Consequently, these individuals may not experience the same results as others who are able to lose pounds using the same diet plan.

Other Connections between Weight and Heredity

There are many other connections between weight and heredity. The fat found in the abdominal areas of many men, which is most common during the middle years, appears to be genetically linked. Genetics can also determine a person's metabolism, which is responsible for the way a body digests, stores and utilizes fats and other nutrients. The relationship between the amount of muscle and fat on a body, which greatly affects a person's physical appearance, is another factor that is believed to be determined through genes. Even preferences for certain types of foods, especially those that may contribute to weight gain, and exercise activity, which can help reduce weight, can be influenced by genetics.

DNA Testing and Weight Loss

The increased knowledge of genetic factors in obesity and weight loss has spawned a new medical industry that uses this information to help men and women achieve healthier weight levels. This technique involves the collection and analysis of DNA samples to determine how a person is genetically conditioned to absorb nutrients, leading to the creation of a genetic "profile." The information is then used to establish a diet and lifestyle that can help a person control his or her weight. One study showed that so-called genotype-appropriate diets have helped some individuals reduce their body weight by more than 5 percent, or more than double the reduction experienced through conventional dieting methods.

Other health experts have questioned the role of genetics in weight control. It was noted in one study that while the inheritance of certain physical traits has existed throughout human history, high rates of morbid obesity have only appeared in recent decades. Some specialists have therefore suggested that those with weight problems invest in more nutritious foods and a membership to the nearest gym as a means of shedding pounds, and avoid costly genetic examinations. Addison Appleby is a science and technology writer from Tucson, Arizona whose interests range from web design to renewable energy to genetic testing. She currently works for a Tucson drug testing company.