It’s no secret that America is in the middle of an obesity epidemic—we hear about it all the time. But experts say there’s one major element that isn’t being discussed: There are different types of obesity. That’s a fact several doctors note in a new article in the New York Times, explaining that it’s why two people can have the same amount of excess body fat, be the same age, of the same socioeconomic class, same race, and same sex, but a weight-loss treatment will work for one and not the other. Instead, like cancer, there are many forms of obesity—and Lee Kaplan, M.D., director of the Obesity, Metabolism, and Nutrition Institute at Massachusetts General Hospital, tells the Times that there are at least 59 types.

Beyond the differing types of obesity helping to explain why there’s no one-size-fits-all approach to combatting it, this might give a hint as to why obesity has become such a problem in the U.S. According to research published in the journal JAMA Internal Medicine in 2015, there are now more obese than overweight adults in America. Not only that, the majority of U.S. women and men are now considered overweight or obese.

Michael Russo, M.D., general surgeon specializing in bariatric surgery at MemorialCare Center for Obesity at Orange Coast Memorial Medical Center in Fountain Valley, California, tells SELF that obesity can largely be put into three different groups—patients who have obesity due to genetics, diet, or environmental reasons—and some may have obesity as a result of multiple factors. “It’s important to recognize that obesity is a kaleidoscope of contributions,” he says. “All obesity isn’t created the same.”

Fatima Cody Stanford, M.D., M.P.H., M.P.A., instructor of medicine and pediatrics at Harvard Medical School and obesity medicine physician at Massachusetts General Hospital, tells SELF that some of the most common forms of obesity are diet-dependent (meaning, changes to someone’s diet may impact their weight), exercise-sensitive (becoming more active may help someone lose weight), and stress-induced. Many women also have obesity that occurs as a result of hormonal changes, such as starting their period, being pregnant, or going through menopause, she adds. “These big hormonal shifts can be significant in terms of weight gain for women,” she says. Other forms of obesity are due to genetic syndromes and sleep or metabolic issues. And while some forms of obesity don’t respond well to medication, others do, Stanford says. “Some people change their exercise regimen or diet and lose weight,” she says. “Others may try several different things, get on one medication, and lose 100 pounds.”

While Marc Leavey, M.D., an internist at Baltimore’s Mercy Medical Center, tells SELF it’s important to encourage people to develop healthy eating behaviors and an active lifestyle, he says there are often other issues that impact their treatment and have to be addressed in order for patients to see weight-loss success. That may mean helping someone to get their diabetes under control or working to lessen the symptoms of other chronic conditions, while also providing education on making good food choices and exercise. “We have to treat those things as well,” Leavey says. “You have to address people where they are.”

Unfortunately, unless a person has a chronic disease or syndrome, there’s no blood test to tell what type of obesity they have. That’s why Stanford says she has a thorough conversation with patients during their initial visit to try to pinpoint what may be the cause of their obesity, including asking about when their obesity began, whether their parents also suffer from it, and how their parents responded to treatment. “If I hear a patient say that a parent had weight-loss surgery and responded quite favorably, I might consider that as a treatment,” she says, noting that the reverse is also true—if someone’s parent didn’t respond well to a certain treatment, it may not work for the patient either.

For people who are obese and want to lose weight, Russo says it’s a good idea to start by seeking help from a primary care physician for guidance. If that doesn’t help, he recommends seeking help from a weight-loss clinic. “They’re going to be able to provide the most comprehensive treatment,” he says. Stanford also recommends seeking out a doctor who is board-certified in obesity medicine—search on the American Board of Obesity Medicine’s website to find one near you.