As many as 7.8% of overweight and 11% of obese adults have asthma, making breathing more difficult. For some people, asthma is easily controlled with lifestyle changes and medications. But many individuals who are overweight or obese struggle with severe asthma, a form of the condition that’s difficult to manage. Thanks to research efforts, new data is strengthening the link between weight and severe asthma. Fortunately, we’re also discovering how weight loss can help manage severe asthma symptoms. If you have severe asthma and are interested in losing weight, your doctor can help you develop a plan for losing weight while staying healthy. Severe Asthma and Weight Severe asthma is a form of the disease that is very difficult to control, even with control and rescue asthma medications. For many, severe asthma increases the frequency and seriousness of asthma symptoms. People living with severe asthma visit emergency rooms more often compared to people with milder forms of the disease. And those with the condition are more likely to use a combination of different asthma medications to try to control their symptoms. But research shows people who are overweight or obese don’t respond as well to asthma medications, making symptom control more difficult. While data suggests a link between higher body weight and asthma severity, it’s not fully understood why overweight or obese people are more likely to have severe asthma and a poorer response to asthma medications. Doctors have several theories to help explain the relationship between obesity and asthma. Inflammation’s Role Chronic, system-wide inflammation is common among people who are overweight or obese. Certain proteins, like leptin, are produced by fat cells. Since obese individuals have more fat cells compared to people who are not obese, they typically have higher levels of leptin. Leptin promotes inflammation and may make airways more likely to swell and narrow in response to allergens, leading to severe asthma symptoms. Additionally, obese individuals typically have lower amounts of proteins that help prevent inflammation. Decreased Lung Function Some researchers theorize carrying extra fat around the midsection crowds the lungs, preventing them from expanding fully each time a breath is taken. Studies also suggest obese individuals typically have a lower functional residual capacity (FRC), which is the amount of air remaining in the lungs each time someone breathes out normally. It’s thought that lower FRCs may cause small airways in the lungs to close, making breathing harder. Some researchers speculate smooth muscle tissue in the airways may also be more sensitive to allergens in overweight or obese individuals. Lifestyle Factors and Related Medical Conditions Certain lifestyle factors and other medical conditions that are common among overweight or obese individuals, like lack of adequate daily exercise, may play a role in the severity of asthma. While it’s unknown which, if any, factors increase the likelihood of severe asthma, some factors, like poor diet, gastroesophageal reflux disease (GERD), and obstructive sleep apnea may all make it more difficult to control asthma symptoms. Weight Loss for Better Asthma Control Losing weight is difficult, but research shows it’s beneficial for helping control severe asthma. According to some studies, people who lost between 7.5–10% of their body weight over 6 months achieved better symptom management and visit emergency rooms less frequently compared to those who don’t lose weight. Severe asthma may make it more difficult to exercise as part of a weight loss program, but eating a healthy diet and avoiding foods containing high amounts of fats may be helpful. Less intense forms of exercise, like walking, may help boost weight loss along with dietary changes. Before beginning any weight loss program, especially if you have severe asthma, talk with your doctor about staying as healthy as possible while you work to lose weight. The link between weight and severe asthma is strengthening. As we learn more, maintaining a healthy weight to help achieve better asthma symptom control is becoming a more important factor for people with the disease. Your doctor can help you develop a plan for healthy eating and exercise that allows you to lose weight while controlling your asthma symptoms as much as possible.