Why can you grow fatter by choice, but cannot grow taller or become shorter? – Innovita Research

Why can you grow fatter by choice, but cannot grow taller or become shorter?

We are shaped by our environment and our genes. If your parents are tall, you are likely to grow tall yourself. On the other hand, if you eat a lot of junk food, you are also likely to grow fat. But how do the genetic and environmental factors interact? How our genes and environment influence BMI and height? Scientists from the University of Queensland decided to figure it out.

There are genetic variations for both BMI and height, but only one of them is more heavily controlled by environmental factors. Image credit: Raimond Spekking via Wikimedia (CC BY-SA 4.0)

Scientists analysed data from more than 300,000 individuals with a known height and BMI. They looked for genetic variations associated with the variability of each of those traits. Researchers found that while BMI is influenced by genetic factors, it can vary widely even between individuals with the same genetic variation. This could be because environmental factors influence BMI by increasing or decreasing the effect of inherited genetic variations. However, the same cannot be said about the person’s height.

This study showed that height in this sense is opposite from BMI in a way that it the genetic effects that influence it are very stable from one environment to another. In other words, if you have genes making you tall, you will grow tall in virtually any environment.

And this is not that surprising – BMI is more easily controlled by behavioural factors, such as food choices and exercise. It is not surprising because it is also true for other health areas. For example, you may have genes for very healthy lungs, but you can mess it up completely by smoking. You may have genes for a healthy BMI, but you may ruin it by eating fast food for breakfast every day.

Jian Yang, leader of the research team, said: “Height can be affected by environment for sure, and height can also be affected by genes, but these things seem to be independent. It’s important to know this because it can enable us to search for elusive environmental factors that might be interfering with the function of a gene”.

This may seem obvious at first, but the subject of the relation between environmental and genetic factors has been elusive for some time. Of course, scientists know that BMi is easier to change than height. In fact, you pretty much cannot naturally control your height by means of diet and exercise.

But why is that? Why some factors are influenced by the environment while others are not? And this is why this research is important – it serves as a design for future studies that will help us understand why a genetic effect at a particular gene locus is sensitive to environment. This will bring advancements in biology and medical science.

Can you imagine a world where your height depended on your diet? You would get shorter as you would eat junk food and you would grow taller by choosing a healthy diet. Maybe then people would be more interested in a healthy lifestyle.


Source: University of Queensland