Obesity: Genetics or Habits?
By: Hana ElShiaty
As of the year 2013, 400 million people around the world are classified as obese, that means they have a Body Mass Index (BMI) of 30 or higher (“Obesity:”). Obesity is now considered an epidemic that is rapidly spreading with its devastating repercussions on one's health. Over the past few decades, the attention has been centered around unhealthy food choices and lack of physical exercise as the major factors leading to obesity, and our means of prevention and treatment has ever since been changing our unhealthy habits into healthy
ones. However, in some situations, it seems as if habits are not an absolutely sufficient explanation like how some very skinny people consume thousands of unhealthy calories and don't gain weight; so, could there be other reasons to this obesity epidemic that we just might be unaware of? Well, according to a study done in the University of California, Los Angeles (UCLA), genes could actually be responsible.
New research, in UCLA, suggests that obesity is associated with the body's genetic makeup; in other words, how our bodies react to the food we consume is determined by our DNA. In the study, experimenters observed and measured several groups of newborn mice obesity traits, fat tissue, intestinal flora, and global gene expression over the course of two years. In their first eight weeks of life, the mice were fed a balanced diet. Then, they were switched on to a high fat and high sugar diet for another eight weeks. The researchers measured the effect of such a diet on the mice's BMI and discovered drastically diverse reactions between the individual mice that their body fat percentage increased from between 0 to over 600 percent. (Thomas) Although all the mice were given the exact same diet and daily routines, their bodies reacted in different ways; this entails that weight is dependent on each individual's own genetic makeup, regardless of the type of food consumed.
The idea that genes could lead to obesity is based on the fact that genes do determine how our bodies harness, use, and release energy from food. Human beings must maintain a balanced ratio between energy storage and energy expenditure in order to have a normal body weight, but variations in this process tend to occur. Whenever the scale is tipped off at one of the two ends, either excessive weight loss or weight gain occurs. Obesity occurs when the body stores food or energy much more than it consumes as is encoded in the body's DNA. Scientists have attempted to explain the widespread occurrence of this imbalance in favor of energy storage that leads to obesity between individuals with the “Thrifty Gene” hypothesis. This hypothesis explains how nature has favored, since ancient times, those individuals who can store energy more than the others who don't as the former are able to overcome times of famine and environmental challenges, and so are better at survival(“Obesity”). Therefore, through natural selection, these individuals that store more than they release reproduced more and passed on their genes to their offspring, causing a shift towards individuals carrying genes that lead to energy storage between humans (“Obesity”). However, now that we are living in societies where food is abundant, such tendency to store energy that is found within some people's genetic makeup is pushing us towards obesity, and genetic changes within a population occur too slowly to change such a phenomenon.