Have you asked the question why in some families obesity or high body weight is more often than in others? Fat distribution is the result of interaction between genetic factors and environmental factors. Heredity in obesity has become a very important factor because of the large number of people with obesity.
Genetic studies of obesity may help to identify groups of people who are resistant to environmental changes, and new methods of treatment obesity.
Heredity, responsible for 25%-40% of obesity cases
Information regarding the contribution of genetic factors on the occurrence of obesity initially came from studies done on families, twins and adopted children. These studies have suggested that heredity is responsible for obesity at a rate of 25-40% in families with affected individuals and 50-80% in twins. It has been shown that if one parent is obese, the child has a 40% risk of becoming overweight, and if both parents are obese, the risk rises to 80%. Most metabolic characteristics come from the mothers. Children whose mothers are overweight are 75% likely to become obese.
Genetic heritage is visible in girls. If the risk for childhood obesity that has mother of normal weight is under 4%, it increases exponentially in case of overweight or obese mothers.
20 genes involved in obesity
Over 90% of cases of obesity are caused by mutations appeared in several genes. Approximately 20 genes and three different mechanisms of action have been found to be involved in the pathogenesis of obesity. However, only some of these genes undergo changes in severe obesity. Induced gene mutations observed in some morbid obesity cases, are correlated with distinct features in terms of laboratory, clinical manifestations and the neuroendocrine profile.
FTO obesity gene
The link with obesity is FTO, called the obesity gene. This gene plays a role in weight control, increasing people’s predisposition to gain weight, without increasing food intake. The researchers found that this gene action start at age 7, by disrupting hunger. FTO gene is found on the persons who are hunger even if they just ate.
The FTO gene is actually a pair of genes. People who own both versions of the mutated gene have a higher risk to become obese than those who inherit only one FTO gene. It seems that a person in six has this obesity gene. Effects can be countered by a healthy lifestyle and especially through sustained physical activity.
Latest studies reveal that the majority of genes involved in obesity act in the brain. This produces a shift in feeding behavior of people who have these genes, the intake of sufficient amounts of food being followed by the appearance of satiety.
Obesity is a disease caused by a complex of factors, including heredity and environmental factors (psychological, behaviors, habits, socio-cultural factors). Heredity is a major factor contributing to obesity. However, inheriting a tendency to obesity does not mean you cannot lose weight, it just means you must deposit a greater effort for this.