Does it seem like, no matter how hard you try, you just can’t lose your excess weight?
It’s a common story – you have those skinny friends who can eat everything in sight and still stay in shape, yet you just have to look at a cookie and the scales nudge up a pound or two.
Most people assume that you sit at home scoffing processed and junk foods but that couldn’t be further from the truth. It’s so unfair – yet it’s just one of those inexplicable things…isn’t it?
Well actually, there may well be something else in play!
Over the last number of years, a growing body of research has been linking our genetics with obesity.
Does this mean that, for some people at least, their weight is outside of their control? Let’s find out.
Being Overweight or Obese
Firstly, here’s a really quick overview of the obesity situation today.
The World Health Organization defines being overweight or obese as having “abnormal or excessive fat accumulation that may impair health”.
Studies have highlighted an increased risk between excess weight and cardiovascular disease, type 2 diabetes, gallstones, gout, osteoarthritis, asthma, other respiratory difficulties and certain cancers.
Children are seriously suffering from excess weight too – with almost one third of under 18s classed as being overweight or obese.
These shocking statistics show that childhood obesity has more than doubled in children and quadrupled in adolescents in the past 30 years!
Is Weight Gain Outside Of Our Control?
It’s controversial to say that weight gain is out of our hands but some studies have shown that could well be the case.
In a study of 540 adopted children, researchers wanted to discover if genetics or environment had the most impact on weight.
If environment is most important, then their weight should be in line with their adoptive parents’. But if it’s genetics, they would be a similar weight to their biological parents.
The results of the study show a strong correlation between the weight class of the adoptees and their biological parents, while there was “no relation” with their adoptive parents!
Another study looked at identical twins who had been brought up in separate homes and did not know each other. It’s surprising to think that there were enough twins out there to fit this profile – but there were!
93 sets of identical twins raised apart, and 154 sets raised in the same home, were studied – with the weights of all sets found to be extremely similar.
These findings led researchers to claim that genetics plays a substantial role in weight whereas childhood environment has “little or no influence”.
In fact, their work showed that up to 70% of the variation in weight was down to genetics. That’s huge!
But more recent research casts doubt on this high figure.
When both adoptive parents are overweight, an adopted child is up to 21% more likely to be overweight than if they are raised by healthy weight parents.
Biological children of overweight parents are 27% more likely to be overweight – just 6% more than adopted children, a much lower number than the 70% posited by the twin study!
How Genes Can Make You Fat
While it’s unclear to what extent our genes influence our weight, it’s accepted that genetics do indeed play a role in body mass index. Here are a few of the ways it can do this.
Some genetic conditions can directly affect weight levels as in the case of those with Prader-Willi syndrome, Bardet-Biedl syndrome, Cohen syndrome, Ayazi syndrome or MOMO syndrome.
However, these conditions are extremely rare and count for only a miniscule fraction of cases of obesity in the United States.
The ‘Obesity Genes’
However, there are other, more common, genetic traits that can be linked to obesity.
In 2007, researchers first identified an obesity-related gene variant known as FTO, which is said to be “fairly common”. Those who have this variant have a 20% to 30% higher risk of obesity than people who don’t have it.
Since that breakthrough research, studies have identified over 30 genes on 12 chromosomes that are thought to affect body mass index – although FTO seems to have the greatest influence on weight.
It should be noted that 40% of Europeans and 42% of Southeast Asians carry this obesity-risk variant, while just 5% of Africans do.
Clearly, there is some disparity among those carrying the gene and those who are actually obese.
It seems that not all those with the obesity gene will become obese, and that many cases of obesity have environmental (or other) origins, rather than genetic ones.
Genetics and Fat Type
According to recent research, published in August 2015, our genes can indirectly affect our weight levels in another way.
The scientists behind the study found a ‘genetic switch’ that determines whether we burn extra calories or save them as fat.
This switch causes our fat-producing cells to become energy-storing white fat cells instead of energy-burning beige fat.
In tests on normal-weight mice, the researchers found that, when they disrupted one of the genes in question, the mice lost over 50% of their body fat, although they ate and exercised as much as other mice did.
Even when fed a high-fat diet, the mice failed to gain weight because the cells became beige fat, rather than white fat.
Interestingly, in this study, the FTO gene appeared to have no link with obesity!
Hormones and Obesity
Hormones play a huge role in our health, which is why it’s so important to keep yours balanced.
What has genetics got to do with this hormone you ask?
An inherited condition known as congenital leptin deficiency exists – where the body has low levels of this hormone, leading to early-onset (childhood) obesity.
In fact, a 2015 paper, which looked at two siblings – a 9 year old girl and her 6 year old brother who were severely obese – found that congenital leptin deficiency was to blame.
Treating the two children with leptin led to “rapid improvement of eating behavior and weight loss”.
But, if you’re struggling with your weight, it’s unlikely that this is your issue.
Congenital leptin deficiency is usually diagnosed in the first few months of life and is an incredibly rare disorder with only a few dozen cases being reported in medical literature.
Am I Destined to Be Fat?
If you’re one of those people who is genetically predisposed to gaining weight you may be feeling hard done by.
But you should know that, just because you have a certain gene, you’re not necessarily destined to be overweight.
Remember the 2015 study of adopted children I described earlier? In it, the researchers found environment and lifestyle choices play a far bigger role in weight management than genetics seem to.
“Despite obesity having strong genetic determinants, the genetic composition of the population does not change rapidly. Therefore, the large increase in obesity must reflect major changes in non-genetic factors”.
With that in mind, let’s look at two hugely important non-genetic factors you DO have influence over.
A 2014 study, which looked at the diets and weights of over 37,000 people, found that eating fatty and fried foods can interact with the obesity genes, increasing the risk of weight gain.
How much you eat matters too. It’s now easier than ever to grab a quick snack or meal on the go no matter where we are, but sometimes we don’t even need it.
So keep a careful watch over your food and caloric intake and you’ll find it a lot easier to maintain a healthy weight.
The Mayo Clinic recommends at least 150 minutes a week of moderate aerobic activity or 75 minutes of vigorous aerobic activity, along with strength training exercises at least twice a week.
When it comes to weight maintenance or weight loss, you may need to do more than this…but it will be well worth your efforts!
Research has shown that getting enough exercise can counteract some of the gene-related obesity risk.
A 2008 study, on over 17,000 people, found that inactive people with the gene had greater BMIs than inactive people without the gene.
But, people with the gene who regularly engaged in exercise had similar BMIs to those without the gene.
What’s more, an analysis of 54 studies, on nearly 240,000 people, discovered that while those with the FTO gene variant had a higher risk of obesity, exercise dramatically lowered their chances of becoming obese.
Active adults with the gene had a 30% lower risk of obesity than inactive adults who carried the gene.
Clearly, some studies have shown a strong link between genetics and body mass. But, many other cases of obesity are down to poor lifestyle and dietary choices.
Even if you are one of those that carry the obesity gene, a large body of research suggests that how these genes express themselves is mainly up to YOU.
Like the researcher J. Lennert Veerman said in a 2011 paper: “genes may co-determine who becomes obese, but our environment determines how many become obese”.
Eat right and exercise and you’ll be the healthiest version of yourself that you can be.
I’d love to hear from you – what’s your take on this research? Do you think we have control over our body weight?