Ever wondered why certain people who consume lots of carbohydrates remain thin and skinny, while the others plump up into obesity?
It has got to do with your genes and believe and it or not, your saliva.
According to the journal Nature Genetics, a study published in March 2014 looked at the relationship between body weight and a gene called AMY1, which is responsible for an enzyme present in our saliva known as salivary amylase.
As soon as we eat food, it comes into contact with this enzyme which starts to digest the food, and this continues into the gut.
But here's the rub, and what could explain why some of us digest carbs more efficiently than others. According to the researchers at the Imperial College of London, we don't all have the same number of copies of the AMY1 gene. The more you have, the better you'll digest carbohydrates and the knock-on effect is that you are skinnier.
Professor Philippe Froguel, Chair in Genomic Health at Imperial College London, and one of the lead authors on the study, said: “I think this is an important discovery because it suggests thathow we digest starch and how the end products from the digestion of complex carbohydrates behave in the gut could be important factors in the risk of obesity.
The research showed that the fewer copies of the AMY1 gene you carry, the higher you are at risk of being overweight.
They believe that higher numbers of copies of the salivary amylase gene seen in some people have evolved in response to a shift towards diets containing more starch since prehistoric times.
They go on to say that the chance for people with less than four copies of the AMY1 gene to be obese was about eight times higher than those with more than nine copies of the gene.
The research could be a valuable tool for dieticians. By focussing on a person's digestive system, their genetic make-up and number of AMY1 gene copies they have, they could better recommend dietary changes to lose weight, including reducing carbohydrates as part of a healthy eating plan.
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