Weight management & fat distribution: Does Genetics have an upper hand over diet?

Weight loss- by name itself appears simple – you eat less, eat healthy, burn more & indulge in more physical activity both-exercise & non-exercise(NEAT) related. However, there are folks who may face challenges in burning that extra pounds &/or maintaining weight loss. To make the matter worse, people may regain weight after shedding that extra fat. So what is the reason behind it? Is it diet? Lack of physical movement? Genes or something which you are not very well aware of: Genes- Environment interplay?

Increase in obesity rate has become a cause of worry, specifically in the US, with one-third of adult being obese or overweight. Obesity can lead to a lot of other lifestyle diseases such as cardiovascular diseases, high blood pressure, etc. By indulging in healthy diet & consistent physical movement & workout, you can reduce body weight & improve your metabolism. A lot of weight loss plans focus on creating calorie deficit of 500 calories a day to drive weight loss of a pound per week.

When it comes to people who consume less to shed weight (which is actually a short term strategy), they generally revert to their original weight & body structure in 1 to 3 years. It is considered a great achievement if one can maintain 10% of weight loss.

Your ability to lose, maintain or gain weight is a function of genetics and environmental & behavioural factors. However the question arises what role does your genes play in weight loss as compared to healthy diet. What is the driving factor – genetics or diet?

The point is that extra pounds on your stomach has to come from somewhere! Are your weight problems during childhood inherited from your parents? Maybe or maybe not? Or it is a mix of both genetics & diet.

Genetics play a major role in your body composition when it comes to body fat. Your body is structured to store fat at different places depending upon gender, age & family genes. If you are a woman, you will have more fat than men since fat plays a major role in reproduction. Essential fat for men & women is 3% & 8%-12% respectively. Genes determine whether females will carry more fat on glutes & thighs or upper body. Men, on the other hand, tend to carry fat on their abdomen and also other places. Storage of fat irrespective of gender plays an important role in influencing health risk. Could genetics make your body to have set body composition? This theory suggests that your body may prefer a certain weight range. However ideal weight range can be genetically altered by environmental factors. A recent review published substantiates the fact that central adiposity, the fat around the abdomen area is inherited even after BMI is accounted for. Genetics influence gender specific fat distribution & DNA variants impact maintenance & predisposition of body fat as well as body shape.

Are there some specific genes impacting fat distribution & weight management? Let us dig into more detail!

Fat genes vs skinny genes: FTO gene (discussed earlier) is associated with fatness and plays an important role in determining body fat composition & obesity. FTO accounts for approx 1% of BMI heritability & is involved in food intake regulation. It is associated with increased total energy intake & childhood obesity. Certain studies have shown that FTO does not contribute to adiposity. In other words, the FTO gene responds well to weight loss interventions. Change in diet & exercise habits impact FTO’s role in obesity. Thus, we can say that genetics & its interaction with the environment makes a bigger contribution to where we store fat.
Although weight loss is simply calorie in vs calorie out, it is much more complex. When it comes to the impact of your diet in body composition, the thermic effect of food is also to be considered. Diet induced thermogenesis describes the amount of energy expended above the resting metabolic rate to digest food. Protein has a higher thermic effect as compared to fat & carbohydrates. Therefore we burn more calories when we have high protein content in our meals. However this is not related to what we eat but how we eat that contributes to the thermic effect of food. Eating quickly reduces the thermic effect of food. This essentially means that when you chew less, we may decrease activation of important mechanisms in the nervous system that contribute to the digestion process.

In some cases, genetics do have influence on your weight management & body composition but chances are unless you are carrier of or devoid of chromosome 16, genetics alone aren’t keeping you from losing weight. It is interaction between your genes & environment that impacts your fat storage, weight management & body composition.