With our jeans tightening, many of us at some point have asked this question to ourselves that why does it happen that some people eat more than us and still the pointer of their weighing machine don’t sway as much? The answer lies in there and your very own genes !
Yes! it’s true that the genes play a role in our body metabolism. Metabolism is the process by which your body converts what you eat and drink into energy required to do the work. During this biochemical process, calories in food and beverages are combined with oxygen to yield energy. Obese people who claim to have “slow metabolism” are proven right by some of the scientific discoveries that relate being overweight with reduced metabolic activity.
Dr. Sadaf Farooqui along with researchers at the University of Cambridge has discovered that the gene KSR2 regulates body metabolism. They worked on two groups of people. One group had people who were obese since they were 10 years old and other was the control group. They found that 2% of obese people in the group had a mutation in the KSR2 gene. The percentage sounds less but it does not mean that only 2% of people were obese because of this gene but 98% of people had obesity probably because of other genes that control metabolism and weight. This gene is responsible for other scaffolding proteins of the body which make sure that the hormones like insulin are correctly processed in the body to regulate how cells grow, divide and use energy. The people who have a mutation in KSR2 gene have increased the urge to eat and a slow metabolic rate. They are not able to burn off the fat they consume and that is because they gain weight.
Dr. Farooqui concluded his discovery with reference to a term called epigenetic where environmental factors and lifestyle choices decide the genes being either on or off. Hence, in general, it is assumed that the person’s lifestyle puts a great impact on the health and body metabolism.
If you are fat and overweight then there is a possibility that you might me having a “fat gene”. The story of the fat gene begins with another study done by Professor Chin-Chung Hui, of the University of Toronto, on the gene called FTO (the fat-gene) and its regulatory protein IRX3. The protein IRX3 regulates body metabolism and energy expenditure. The protein IRX3 interacts with FTO gene and causes obesity. Researchers found that mice deficient in IRX3 protein are 30% slimmer than their counterparts despite having the same amount of food and doing physical activity. These “slim mice” did not gain weight even when fed a high-fat diet. They were better in metabolising glucose and fat. These IRX3 deficient mice had smaller fat cells and increased levels of brown fat which is helpful in burning up the unhealthy white fat.
Researchers also say that this IRX3 protein also has functioned on the hypothalamus – a portion of the brain known to regulate feeding behavior and energy expenditure. Overall, this “fat gene“has somehow opened the doors for the discovery of an anti-obesity drug which most of us in current generation dream of. According to an article in The Hindu, the gene responsible for obesity in Indians was identified by Dr. Kumarasamy Thangaraj of Hyderabad-based Centre for Cellular and Molecular Biology (CCMB). He found that the gene THSD7A is associated with obesity. THSD7 is a neural N-glycoprotein which promotes the formation of new blood vessels (angiogenesis). Angiogenesis, in turn, modulates obesity, adipose metabolism, and insulin sensitivity. Dr. Thangaraj explained that the gene is present in everyone, but when there is a mutation in the gene then there is a likelihood that person carrying the mutated gene will end up being obese. Obesity is a multigenic condition. Despite being a multigenic condition, people having the mutation can take measures to avoid obesity.
Another skilful work was done by Dr. Joseph Majzoub and his colleagues to explore why most people gain weight too easily while others eat much and do not gain an ounce. They observed that deletion of the MRAP2 gene leads to fat mice who gained more weight due to fat accumulation in the body than their siblings while eating the same amount of food. According to them, MRAP2 is a helper gene which acts on the brain and giving a signal to another gene which is responsible for controlling appetite. So if the helper gene is deleted then the whole signalling would be disturbed and the mice would crave for food. Hence, this is not just because you eat a lot of food, in fact, it is the slow metabolism of the body which is storing more unprocessed fat and making you look fat. As the scientist said, this discovery would definitely change people’s perspective of seeing obese people as those who lack self-control.
So, after referring to these studies we can conclude that there are some genes in our body that either alone or by participating together in signalling pathways control the process of fat metabolism in our body. Too much food intake is not the only reason for people being overweight. These discoveries have paved the path for many therapeutic strategies to target problems like obesity and diabetes. The studies done so far are like pieces of a puzzle. More pieces like these need to be discovered and arranged together to have a breakthrough in the field of health and medicine. The idea of anti-obesity drugs can be a success story in coming years. Many people can feel happy about the fact that it is not always your fault if you are overweight but it is something in your genes. There may be the metabolising gene, the fat gene, the regulatory protein or something else in your genes that are playing their games well and succeeding in storing unprocessed fat in the body. So next time when someone taunts you about being fat you can explain your point outside diet.