Envious of those naturally thin types who never set foot in a gym, while you’re battling the bulge daily and working up a sweat on the treadmill? You may have reason to be the smug one: Some evidence suggests that thinner isn’t necessarily better.For years, health experts have been trying to figure out if fitness trumps weight when it comes to living a long and healthy life. A 2007 study in the Journal of the American Medical Association found that people who are overweight and fit are less likely to kick the bucket prematurely than those who are sedentary and skinny. However, other research suggests that exercise can’t undo the damage of carrying too much body fat.Now, the most recent study to weigh in on the controversy provides some silver lining to those who work out but never see their scale go down. According to the findings, published in the Journal of the American College of Cardiology, being fit helps defend against—but not completely erase—heart disease risks, even if you’re overweight.But with all of this back and forth, what’s the final word on the fit-and-fat debate? We asked top experts to pick apart the science and give us the lowdown on what it means.MORE: Lose Fat With Body Confidence!Keep the Focus on FitnessPeople pile on the pounds and fall out of shape as they get older, upping their risk for all kinds of diseases, explains Duck-chul Lee, Ph.D., the most recent study’s author and a post-doctoral fellow in the department of exercise science at the University of South Carolina. What his study found was that simply maintaining your middle-aged weight and fitness levels will help lower your disease risk. “Many people start exercising to lose weight and will stop because they didn’t lose weight and were disappointed,” says Dr. Lee. He believes that working out to maintain your current fitness level is a much more attainable goal that provides plenty of health benefits.Cardiologist C. Noel Bairey Merz, M.D., director of the Women’s Heart Center as well as the Preventive and Rehabilitative Cardiac Center at Cedars-Sinai Heart Institute, who has also done research on the debate, agrees. Her message to patients is simple: Focus more on exercising than on the number on the scale. “We have this idea that if everyone looks like an underweight model, you’re going to live forever,” says Dr. Bairey Merz. “That’s not what our research shows. The most important take-home message is when people lose weight, we don’t find that they live longer, but when we people get more fit, they clearly live longer.”GALLERY: Healthy Foods That Satisfy Your Daily Cravings Lean and Fit Beats Fat and FitThat said, working out regularly doesn’t give you permission to eat whatever you want or ignore your scale altogether, cautions David Frid, M.D., a cardiologist in the Preventive Cardiology & Rehabilitation department at the Cleveland Clinic. Even if a patient is doing something that’s helping her health, another (bad) habit could negate those benefits. “If you’re overweight and you start exercising, you’re going to lower your disease risk,” says Dr. Frid. “However, somebody who is maintaining an active level of fitness and has a lot of body fat is still at a higher risk of diabetes, high cholesterol and high blood pressure.”That’s why your best-case scenario for good health involves a one-two punch: bringing your weight down and being active. If you can’t do both, says Frid, strive to come as close to your ideal weight as possible by increasing your physical activity.Bottom Line: For people whose sweat sessions aren’t making them any thinner, you’re better off than those who aren’t working out at all—but carrying extra body fat still comes with health risks. Likewise, if you’re naturally skinny (lucky you) that doesn’t grant you a “get out of the gym” free card, if you want to stay healthy. Regardless of the number on the scale, everyone needs to exercise.QUIZ: What’s Your Body Type?Your Get-Active PlanFrid recommends logging 30 to 45 minutes of aerobic exercise three to five times a week. If you’re having a hard time fitting your workouts in, divide and conquer with three 10-minute sweat sessions throughout the day.To stay motivated, focus on the here and now. Research shows that thinking about the short-term benefits of exercise, like a better mood and more energy, will keep you more motivated than long-term goals, like better health or living longer. Remember to make a mental note—or even keep a journal—of how you feel after your workout.Another smart move: Set goals that you can meet. It feels good and will empower you to keep going. Remember that any amount of exercise or weight loss is better than none at all, so celebrate even the small successes. Walked a mile today? Good for you! Just try to reward yourself with a manicure instead of a scoop of ice cream.COLUMN: Easy (Free!) Weight-Loss Plan