So, can we really use that excuse that it is actually our genetic make-up that is making us look fat rather than our lack of exercise and healthy eating?
It may surprise you to know that (in terms of our genes), all human beings are 99.9% similar! This means that a tiny 0.1% of our DNA has the potential to be different and make us unique as individuals. Contributing factors will also include environment.
These tiny variants impact on many things in our bodies, including health and fitness. If we imagine that genes come in two variants, one being a ‘good variant’ and one being a ‘bad variant’, the ‘bad variant’ will be the one that could predispose some people to obesity or diabetes. In history, say 150 years ago, food was limited and most work was labour intensive, those people with the ‘good variant’ would quickly use up much of their energy from the food they ate and possibly would have struggled to consume enough energy as their bodies used it so quickly.
Those people with the ‘bad variant’ not only consumed enough energy from the little food they had, but in addition to this, their bodies were efficient as storing any occasional surplus food ready for times of hardship. 150 years ago, this group of people with the ‘bad variant’ would have found it much easier to survive because their bodies had the ability to store fat.
Fast forward 150 years and welcome to the age of having access to food 24 hours a day, seven days a week. The majority of people no longer have such labour intensive jobs like our ancestors did and our general activity levels are lower too. Therefore, it is people with the ‘good variant’ gene that will thrive more in our modern world, burning lots of energy quickly and providing protection from metabolic disease. The group of people with the ‘bad variant’ will continue to store extra energy effectively which can cause them to be overweight and could lead to metabolic disease.
So, considering the above, how does exercise interact with genetics to alter the amount of fat that our bodies store? The good news is that in the 0.1% of variable DNA, there is a gene that is involved in controlling the burning of fat. It does this in response to hormones known as catecholamines which increase with exercise, therefore the same amount of exercise should result in people with different versions of this gene burning different amounts of fat.
There you have it, although we may differ in the type of fat-burning or fat-storing genes in our bodies, exercise can help to even out the balance. By understanding the interation between genetics and exercise, maybe one day we will be able to predict who will benefit from which types of exercise depending on our genetic type.