Obesity and asthma rates are both increasing. Obesity contributes to the increased incidence and severity of asthma. The mechanism of the influence of obesity on asthma is still unclear. However, there are currently two main theories to explain this mechanism: through inflammation and without inflammation. Airway hyperresponsiveness in obese people as a consequence of reduced functional lung volume. Adipose tissue is considered an endocrine organ, secreting many proinflammatory cytokines, chemokines, growth factors, and adipokines such as leptin, adiponectin, and resistin. Leptin and resistin cause inflammation, while adiponectin mainly has anti-inflammatory properties. Leptin is increased in obese patients, a factor explaining the association between obesity and asthma. Diets high in saturated fat and low in fiber are associated with both increased risk of obesity and poor asthma symptom control in obese and non-obese patients. Reduced physical activity is also associated with obesity and worsened asthma outcomes with a more rapid decline in lung function. Losing weight through diet and exercise controls asthma better than patients who lose weight simply through diet or surgery. Treating obesity means negative energy balance: energy intake is lower than energy expenditure. Therefore, to improve the quality of life in obese asthmatics, it is not possible to simply adjust weight by reducing energy intake; it also needs to incorporate physical activity.