What would you do after gorging on a meal of fries, cheese pizza, and a milkshake? You would probably spend an extra hour in the gym trying to lose all those calories you consumed. But there are a few lucky among us who would lose all those calories without breaking a sweat. How do they do that? Because they carry a rare genetic variant that enables them to reduce levels of certain types of lipids called triglycerides from their blood stream.

This new discovery was made by geneticists from the UK, who make up the UK10K Project, the aim of which is to identify the genetic link to rare conditions. The researchers collected the whole genome sequence data of around 4,000 healthy people and found an association between triglycerides and a gene variant called APOC3.

What are triglycerides?

Most fat in our body is stored in the form of triglycerides. These include fats that we consume through food. Carbs eaten are also converted to triglycerides. When fats or carbs are consumed in excess, it results in overproduction of triglycerides that are released into the blood stream. Generally, exercise rapidly clears these triglycerides from the cells in the form of energy. But lack of exercise causes accumulation, which in turn causes weight gain.

High levels of triglycerides, known as hypertriglyceridemia, have been associated with high-risk coronary heart diseases and inflammation of the pancreas. The APOC3 gene codes for the Apolipoprotein C-III protein, thought to delay catabolism of triglyceride-rich particles. When levels of this protein increase, it results in hypertriglyceridemia.

In order to further prove this theory, the current research scientists compared the whole genome sequences of 4,000 people with the data about their lipid levels. They found a strong correlation between the presence of the APOC3 gene and levels of lipids. The research suggests that people, just 0.2 percent of the population who carry this rare change, typically have lower levels of triglycerides, associated with reduced risk of cardiovascular disease.

Conversely, there are some people who have high levels of triglycerides even when their fat intake is moderate. This can be concluded as a faulty function of the gene APOC3.

The role of this gene variant was also studied in a targeted approach and through coding and analyses of only a part of the genome. These studies published in the New England Journal of Medicine also show how these genetic variants can impact heart disease.

"These three studies independently reporting this finding give us confidence that it is reliable and informative for clinical understanding," said senior author Professor Steve Humphries, from University College London, in a statement. "Once we can understand the mechanism of the protective function of this variant, we can try to use this information to develop novel therapies to help those at risk of cardiovascular disease."