Here’s How Your Genes Impact Your Ability to Lose Weight

A study looked at why some people seem to never gain weight no matter their diet.

Genetics can play a significant factor in a person’s ability to easily lose weight. Getty Images

A new University of Cambridge study may have an answer to the question asked by many frequent dieters: Why can some people eat anything they want and never put on any weight?

In a study published Jan. 24 in the PLOS Genetics journal, university researchers in the United Kingdom compared the DNA of 1,622 thin volunteers, 1,985 severely obese people, and a normal-weight control group of 10,433. They found that thin people have genetics on their side.

“Using genome-wide genotype data, we show that persistent healthy thinness, similar to severe obesity, is a heritable trait,” the researchers concluded in their “Genetic architecture of human thinness compared to severe obesity” study.

Dr. Eddie Fatakhov, a board-certified internist, nutritionist, and co-author of “The Doctors’ Clinic-30 Program” and “Dr. Fat Off – Simple Life-Long Weight-Loss Solutions,” said many studies have compared gene variants from obese patients to patients of normal body weight, but only two previous studies explored the genes of thin people.

“This study is the largest study that has compared the genetic variants among thin people to the control group of normal weight and severely obese patients,” he said. “Based on this study, researchers were able to create a genetic risk score for the development of obesity later in life.”

What did the study find?

Participants studied for their thinness had to have a body mass index (BMI) of less than 18, be in good health, and have no medical conditions or eating disorders. The researchers gathered saliva samples for DNA analysis. The participants were asked questions about their general health and lifestyle.

“I haven’t seen many studies looking at this population,” said Dr. Mir Ali, general and bariatric surgeon at MemorialCare Orange Coast Medical Center in California.

But despite the role genetics may be playing in obesity and slimness, the doctors stress the importance of other factors that can be controlled.

“Genetics does play an important role in determining somebody’s weight, but we don’t want people to think that that’s the only thing that determines somebody’s weight,” said Ali. “There are things that can be done.”