Americans who are overweight are at a higher risk of many diseases including heart disease, stroke, diabetes, and some cancers. Thankfully many of these risk factors improve as an individual returns to a healthy weight through changes in their nutrition and exercise habits. Patients often ask if weight loss is the key factor in this risk reduction or if an active, overweight individual is still at risk for these diseases. As with many questions on obesity the answer is evolving, but some researchers have provided valuable information on the topic.
The question of the impact of an individual’s weight and exercise levels was recently answered in a systematic review in 2010 (Obesity Rev). Fogelholm and colleagues analyzed the health risks and mortality rates between two groups: normal weight and poor cardiovascular fitness, as well as, obese and good cardiovascular fitness. Authors included 36 studies and reported the risk for all causes of mortality was lower in the group of participants who were obese with good cardiovascular fitness compared to their sedentary but normal weight peers. Conversely, in a more detailed analysis the fitness of the obese individuals was not able to lower their risk for all diseases. Authors reported the obese participants with good cardiovascular fitness remained at a higher risk for conditions such as diabetes and cardiovascular disease compared to their peers at a normal weight but poor cardiovascular fitness.
In a more recent review, Barry and colleagues reviewed the medical evidence on the relationship between body weight, exercise or activity levels, and disease risk (Prog Cardiovasc Dis. 2014). Specifically, authors included 10 prospective studies on the association between cardiovascular fitness, body weight (BMI), and risk of death. Participants were broken down into the following groups normal weight and fit, normal weight and un fit, over weight and fit, overweight and un fit, obese and fit, and obese and un fit. They reported unfit individuals had twice the risk of death, regardless of body weight, compared to the normal weight fit participants. This study highlights the importance of improving cardiovascular fitness regardless of body weight.
In summary, obesity is an evolving and complicated topic, but it is clear overweight and fit individuals have less disease risk compared to their overweight, sedentary peers. That being said, being overweight seems to have independent health risks regardless of cardiovascular fitness levels. Individuals are encouraged to maintain a healthy weight and remain active for the greatest reductions in disease risk.