Is being fat genetic? How is this proved?

Looking at Genetic Obesity Research & The Proven Impact of Genes on Weight Gain Susceptibility

When an individual accumulates too much body fat for their height and frame, they are considered to be overweight (25-29 BMI), or obese (30+ BMI) [1]. While many factors contribute to obesity, including physical inactivity, poor lifestyle choices, and the overconsumption of energy (food and drink), research indicates that your genetics are also partly to blame. Individuals with genetic obesity are more susceptible to gaining weight due to genetic changes that impact metabolism, appetite, and the ability to lose weight. Let’s take a look at the link between genes and obesity, how your genetics can impact fat accumulation, and what you can do about it.

What Do Genes Have to Do With Obesity?

When we take a look at the most common reason behind obesity, we see that it is a result of a chronic energy imbalance between how much energy (calories) we are taking in, versus, how much energy we are expending [2]. When we consume too much and are unable to or choose not to expend the excess via physical activity, it gets stored as fat for later use [3]. If we carry the excess fat for too long, it becomes a health problem as it increases our risk of developing health-related conditions such as diabetes, heart disease, strokes, and other serious diseases [4]. But what does this have to do with our genes?

Our brain responds to signals received from your pancreas, digestive tract, and fat tissue by releasing hormones that give our body instructions on what we should do next [5]. For instance, if leptin is released (produced by fat cells), our appetite becomes suppressed (satiety hormone), but if ghrelin is released, we are encouraged to eat more (hunger hormone). Small changes or variants in the genes that release these hormones may cause someone to be more susceptible to obesity.

An Example of This is The Fat Mass Obesity Associated Gene

An example of how variations in your genes can account for a predisposition to obesity can be found with the Fat Mass and Obesity-Associated Gene (FTO). This gene, found back in 2007, is thought to increase the risk of obesity by around 70% if you inherit two high-risk “copies” of it from your parents. Studies show that FTO has a high impact on genetic obesity predisposition [6] and is related to a higher BMI, weight, and abdominal circumference [7], as individuals with the high-risk variant of FTO have increased circulating levels of ghrelin (hunger hormone) after eating [8]. As a result, their ghrelin levels were not being suppressed after eating, leading to a higher likelihood of overeating in future meals.

The great news with the FTO gene is that while it may be one of the strongest genetic contributors to obesity, it is also one of the most responsive to lifestyle and environmental changes. The odds of developing genetic obesity from carrying this gene drops by 27% if you’re physically active [9]. This means that although you may be more susceptible to weight gain, lifestyle changes can have a drastic impact on the overall outcome.

How Much Weight Is Impacted by Your Genetics?

Since 2006, studies looking at genome-wide association have found more than 50 genes associated with obesity [10], most of which have very small effects on overall obesity. However, the Genetics of Obesity: What We Have Learned Over Decades of Research, notes that genetic contribution accounts for 40-50% of the variability you see in body weight status [11]. This percentage drops among normal-weight individuals (30%), and increases to 60-80% in those who are severely obese [12]. However, just because your genetics may predispose you towards obesity, that doesn’t mean that you are destined to be fat.

Can You Overcome Genetic Obesity Predisposition?

Absolutely! The key here is to identify the impact your genes are having on your ability to control your weight. Do you?

• Have frequent hunger urges to eat large meals?
• Don’t feel nearly as full as you think you should after eating?
• Feel out of control when you eat your meals?
• Are you not as active as you should be during the day?
• Find that you store excess energy as fat, easily?

Knowing where you lie within the predispositions above will help you develop strategies for overcoming these issues. For example, if you know that you have a harder time feeling full after meals, try eating smaller portioned meals throughout the day that are filled with protein and fiber-rich foods. Or, if you have a hard time being physically active, consider adding structured exercise into your week via classes that you can attend with a friend (accountability).

The key here is to understand that genetics may predispose you to obesity, but it’s not the whole story, and it doesn’t mean that you’re fated to be fat. As long as you commit to weight loss, understand your current physical status, and then set realistic goals to help you offset any genetic predispositions you may have, you can overcome genetic obesity.