Why Are We Getting So Fat is on SBS Thursday August 10, 8.30pm
The war on obesity is at an all time high, with of Australian adults either overweight or obese and widespread comment in the press about our country getting fatter and unhealthier.
UK geneticist and presenter of Why Are We Getting So Fat (10 Auguat on SBS), Dr Giles Yeo, has been trying to make sense of this epidemic which, according to is now “worse than terrorism.”
While a lot of people say the solution is simple physics - eat less, move more - the actual findings in the lab are far more complex than handing a carrot to the co-worker who guzzles a 2.5 lt Coke at their desk.
Dr Giles Yeo meets with a group of dieters as he explores why the world is having such trouble with weight. Source: BBC
Sure, it doesn’t help that our evolutionary urge to eat is now acting in a developed world where we have so much food available that it outweighs our daily activities. Or that these kinds of culinary options are often highly processed, fried and fatty, with an increase of 45 per cent more take-aways cropping up in the last 20 years, with meals offering average of 1000 calories per burger, chips and soft drink combo or what have you.
But as Yeo discovers, those who have a BMI of over 25 aren’t always just a product of contemporary dining. In a large number of cases, eating more and being fat is also a result of a person’s biological make up which, like anyone with a gene mutation, makes them ‘different’ to the vast majority.
Understanding the FTO Gene
Although there are more than 100 genes that have been linked to obesity, the most common is the Fat-mass and Obesity related transcript (FTO), a protein encoded on chromosome 16 and something Dr Yeo has investigated throughout his career. Every person has FTO; however, some inherit a different version or copy of it, which and weight gain
As much as half of the world’s population has one change to a ‘normal’ FTO gene, making them about 1 - 1.5 kilograms heavier than the average person and 25 per cent more likely be obese, and at least 1 in 6 people carry double this change, making them likely to be 3 - 3.5 kilograms heavier and 50 per cent more likely to be obese.
...it alters your brain structure and function ... leading to people craving and liking the high energy foods much more.
Those with FTO variations are less sensitive to appetite hormones that are released from the gut and fat cells and then signalled to the brain. This has an impact on how hungry you feel by making the brain think that you have have eaten less than you actually, and have less fat on your body than you actually do.
Dr Tony Goldstone of Imperial College London explains the variant affects cravings: "We believe that if you have the double risk variant, it alters your brain structure and function and we know from our brain imaging and some other genetic studies that it may influence how the reward pathways in the brain work, leading to people craving and liking the high energy foods much more."
Dr Giles Yeo and Nathan Hewitt, who lost more than 63 kilograms despite possessing a double FTO gene variant. Source: BBC
Sounds like the gene lottery is bad news, but an experiment that Dr Goldstone conducts suggests that knowing about FTO can be a helping hand - by understanding how the gene can influence them, people with FTO variations can potentially find better ways to ward off obesity.
"It really helps to understand perhaps how for me as an individual, my biology is driving my weight and more importantly, what I can do about it," says one participant.
Exercise
While it's a no brainer that exercise keeps you physically trim, the combination of exercise and having an FTO variation put together has a significant impact on weight loss.
Scientists have discovered that FTO variants have up to a 30 per cent better chance of combating obesity through exercise than those with no risk variants.
Healthy parents
A mother’s nutrition and lifestyle has an impact on the growth and development of her unborn baby, and the intake during pregnancy of foods that quickly release sugar into the bloodstream - such as bakery treats, lollies and alcohol - can have a predisposing effect on the child’s DNA.
According to Professor Keith Godfrey, the path to obsesity is not only down to the genetics a child inherits but but also how genes are switched on or off during life in the womb.
"We’ve always known that mother’s nutrition and lifestyle is really important for the growth and development of her baby," he explains in Why are We Getting So Fat. "There are switches, chemical switches on the DNA which are influenced by the mother’s sugar levels in her diet which tell one cell to be a muscle cell and another cell to be a fat cell, and when there are excessive amounts of sugar coming across the placenta, then there is an excess of fat cells and that excess fat cell complement, it’s with you for ever."
According to Professor Godfrey, a mother’s nutritional intake can be associated with an fivefold increase of childhood obesity.
Okay, so it's too late for us to do anything about this one, but it may help explain a few things.
Encouraging healthy gut bacteria
The action of 'fat genes' isn't always to do with the brain. Recent studies have found that there's something happening down below - quite literally.
Out of the estimated 100 trillion microbes living in our gut, people can have varying levels of christensenellaceae, part of a network of microbes BMI. Those with high levels of christensenellaceae - 1 in 10 people - are and those who have inherited a lower percentage will find it more difficult to stay trim.
However, Professor Tim Spector of Kings’ College, University of London, believes that there are certain foods that people can eat to encourage the good bacteria to grow.
"The more diverse the foods, the more high fibre the foods, the more species of microbes you’re going to get and the more likely you’re going to get the good ones rather than the bad ones flourishing."
Spector recommends this should be based on an "old fashioned Mediterranean diet but without the pasta and pizza". Artichokes, for example, are "fantastic fertilisers for your microbes", as well as full-fat yoghurt and even dark chocolate.
