Obesity: an Answer in Your Genes?
If you've had the same experience as Donna Ridolfino, a clinical nurse supervisor for insurer Aetna who has been struggling to control her weight for more than 30 years, you might be both daunted and relieved by some of the latest obesity research. Daunted by news that the winds against you may be programmed into your genes; relieved that blaming yourself for faulty willpower may be the wrong response.
Ridolfino, 60, has tried everything from the Atkins diet to Weight Watchers, and every time she lost weight, she gained it back -- and more. Then, when the scale registered 354 pounds in 2015, Aetna offered what she considers a "life-changing" breakthrough: a program that would use her genetic code to determine the best weight-loss plan for her. Testing revealed a variant of a gene called MC4R, often referred to as the "appetite" gene, which normally triggers signals in the brain that it's time to stop eating. "I started looking at how other people eat and suddenly I realized this was the key -- my brain didn't know I was full," says Ridolfino, who lives in Myrtle Beach, South Carolina. Working with a weight-loss coach, she has adjusted her portion sizes and learned to pay close attention to signals of fullness coming from her stomach instead of her brain. Encouraged, she also started doing aerobics and strength training three times a week.
[See: 6 Ways Obesity Can Weigh on the Brain.]
"I now have the tools to overcome what was defeating me," says Ridolfino, who has lost 25 pounds so far. "It's not a diet. This is now my lifestyle for the rest of my life."
MC4R is one of hundreds of genes believed to play a role in how people gain weight -- their eating behaviors, how they metabolize fat -- and how effectively they lose it. And even though researchers still have much to learn about how these genes can be employed in battling obesity, there's little doubt that at least some of the propensity to gain weight is predetermined.
Despite ongoing debate about the value now of using genetic data to guide weight loss, several companies have started marketing gene tests to insurers and employer groups, and sometimes to consumers. Ridolfino's plan was created by Newtopia, a company that works with groups to develop personalized wellness programs based on each participant's genetic makeup and behavioral profile. Newtopia counts 10,000 participants so far -- a number it expects to triple by 2018. For consumers, 23andme sells a $199 kit online that promises to help people make the best diet and exercise choices. Dallas-based Genetic Direction sells a $349 test, GxSlim, that offers diet and exercise plans based on 16 genetic traits.
The tests look for mutations in genes that scientists have linked to body mass index, fat metabolism, addictive behavior and other factors underlying a predisposition for weight gain. In addition to checking MC4R, Newtopia's test screens for variations in the gene FTO, which governs how efficiently fat is converted to energy rather than simply stored, and DRD2, a gene believed to be associated with addictive behaviors such as overeating. Aetna found that over 75 percent of employees who pilot-tested the plan lost an average of 10 pounds over a year by focusing on genetically driven recommendations -- cutting fat instead of just calories if their FTO gene was the culprit, for instance, and finding pleasurable nonfattening habits to sub for eating if DRD2 was to blame. Someone who uses GxSlim and has a variant of a gene called GNPDA2 that has been tied to an increased body mass index might be prescribed strength training as a good way to burn fat. Someone who is shown to have certain variants of other genes governing how fat is stored might be told that simple cardio won't work off the excess pounds -- high-intensity interval training is called for.
Dr. Brian Rudman, a doctor in Dallas who specializes in weight loss and uses GxSlim in his practice, says the test results often come as a revelation to patients. "I have people who will say they work out three hours on the treadmill and don't see any weight loss," says Rudman (who is also an investor in Genetic Direction). If the test shows that "a patient is going to have a poor response to cardio," he advises a switch to a regimen of intense bursts of activity. Anyone can lose weight eventually by modifying their diet and trying different exercise programs until they hit on the right one, he says. But without the genetic data "we're working with incomplete information."
[See: 8 Weird Ways Obesity Makes You Sick.]
Maybe so, but some scientists who specialize in genetics argue that the link between genes and weight loss isn't strong enough to justify testing for most people. About 175 genetic variants have been associated with body weight to date, and most of them are still not well understood, says Ruth Loos, a professor of environmental medicine and public health at Mount Sinai in New York. What's more, studies of twins and families have suggested that body weight is determined half by genetics and half by lifestyle factors. "Even people who carry genetic variants that make them prone to gain weight are able to overcome them" with extra effort, she says.
Moreover, it's too early to be sure that the purported links between particular genetic variants and weight-loss strategies are solid. For example, a study published a few years ago in the journal Obesity reported no link between GNPDA2 and favorable changes in body weight in young women who underwent 12 weeks of strength training.
Still, some experts counter, simply knowing you have a genetic predisposition to struggle can be empowering. Blaming oneself for being overweight "actually makes the weight loss much harder," says Gary Foster, chief scientific officer of Weight Watchers International, whereas people who have their genes tested "can say, 'I know the deck is stacked against me. Now I feel resolved that I can do something about it.' " Most people know it's possible to lose weight by eating less and exercising more, says Jeff Ruby, Newtopia's founder and CEO. But "something is missing to spark that behavioral change." The genetic information, he argues, "makes it real -- it taps into their intrinsic motivation to change."
That's the case with Trish Brown, a genetic counselor in San Francisco who has learned from testing her genes that she has a rare genetic variant linked to a buildup of fat in the abdomen and a high risk of metabolic diseases like diabetes, as well as a gene that interferes with her ability to shed pounds in response to exercise. She took her results to a personal trainer, who developed a high-intensity workout designed to be performed three to five times a week. Though she temporarily is sticking to yoga and walking because of surgery, the combination of exercise and a low-fat diet has helped her shed 20 pounds so far.
[See: 7 Reasons to Choose a Plant-Based Diet.]
Brown, 50, is well aware that many questions remain unanswered, and that determined people can lose weight without testing. But knowing her makeup has made all the difference for her, she says. "I spent tens of thousands of dollars at medical weight-loss clinics. I went to Weight Watchers. And I was not progressing on those programs," she says. "When I got my genetic information, I knew it would just take me a lot longer to lose weight. It was very validating."
