“This Genetic Mutation Makes People Feel Full — All the Time”

The journal Cell, published two studies on the biological reasons that some struggle with weight, having to do with appetite, not metabolism. People who gain too much weight or fight to stay thin are hungrier than their thinner counterparts.

Researchers in Britain have discovered that some humans carry a genetic mutation that mutes their appetite. The participants of the study had been thin their whole lives but not because of an unusually fast metabolism.

The study was published in the journal Cell which analyzed data from the U.K Biobank. The Biobank has collected the DNA samples and medical records of over half a million people the ages of 40 – 69 years old.

The same study developed a genetic risk score for obesity.

The two studies help support the genetic factor of weight control vs. metabolism. Many people may struggle with their weight not because they lack will power, but due to their genetic predisposition of feeling hungrier more frequently.

“The study of the appetite-dulling mutation was led by Dr. Sadaf Farooqi, professor of metabolism and medicine at the University of Cambridge, and Nick Wareham, an epidemiologist at the university. “

The gene in question is MC4R, which is often tied to obesity. “Researchers have recorded as many as 300 mutations in this gene, and they are the most common single-gene cause of obesity. Mutations in the gene account for 6 percent of children with severe obesity.”

The mutations kill satiety, or the feeling of fullness. “Normally, when people eat a meal, the gene is switched on and sends a signal telling people they are full. Then the gene turns itself off. But some people carry a rare mutation in MC4R that prevents the gene from working.”

Those with the mutation never feel full, therefore often overeating during and between meals. Their risk of obesity and heart disease is 50% higher than those with the gene.

Dr. Farooqi found that those who have the MC4R gene often feel full. For 6% of the population, the gene is always turned on, therefore, making them feel full constantly.

The study also gauges a person’s risk of obesity by their lower or high “score” of mutations in the genome. The higher the score, the more likely to struggle with weight control. Of course, having a high score doesn’t mean you will be overweight but that you will likely struggle with weight control.

In our society, there is an almost constant temptation to eat. Processed, pre-packaged and calorically high foods are everywhere, including schools. However, scientists believe that you can make a difference in the first eight years of life.

There may be a way to counteract the high score, but how? In the study, 10% of the population with the highest risk scores for obesity are somehow still lean. Does this mean that there may be genes that help counteract this mutation?

“The bottom line is that this opens up a whole new list of questions that can be asked and answered,” Dr. Kaplan said.

Another study found that the benefits of exercise may last longer than many of us might expect, even for those who exercise less later.

To learn more: This Genetic Mutation Makes People Feel Full — All the Time – The New York Times


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