### The Importance of Physical Fitness vs. Body Weight A recent study sheds light on a significant health question: Is physical fitness or body weight more important for our health? The study, published in Obesity, found that higher physical fitness and maintaining body weight reduced the risk of chronic kidney disease in adults with obesity. Interestingly, losing weight alone did not lower that risk. This suggests that preventing weight gain and staying fit are more crucial. Obesity is a known risk factor for kidney disease, which is a leading cause of death in the United States. Extra body fat can lead to hormonal changes that increase body fluid volume, raise blood pressure, and promote insulin resistance. These factors force the kidneys to work harder, leading to damage and scarring. Once scar tissue forms, the damage is irreversible. However, regular exercise may help the body cope with this damage. The study used data from the Multi-Ethnic Study of Atherosclerosis, which followed 6,814 middle-aged adults in six U.S. cities over 10 years. Researchers focused on 1,208 adults who were obese but did not have kidney disease or diabetes at the start. They found that for every 11 pounds gained, the risk of kidney disease increased by 34%. However, losing weight did not decrease the risk, highlighting the importance of preventing weight gain. Fitness was measured by the participants' self-reported walking pace. Those who walked slower than 2 miles per hour were 57% more likely to develop kidney disease than faster walkers. The researchers believe that the anti-inflammatory effects of regular exercise and better cardiovascular health may protect the kidneys. This study reflects a shift in obesity research from focusing solely on body weight to considering other factors that link obesity and disease. For example, a 2022 study found that people who walked faster had a 36% lower risk of dying during the study period. Another study in 2021 showed that starting a regular exercise routine, regardless of weight loss, reduced the risk of early death linked to a high body mass index. It's important to note that intense workouts can be risky for patients with kidney damage. Kidney disease is associated with muscle loss and decreased muscle strength. Therefore, resistance training may be a better option. Recent research suggests that resistance training may improve walking speed in patients with muscle loss better than other types of training. People with kidney disease should consult their physician about their exercise goals. Future research aims to explore how individuals with obesity and kidney disease can lose weight while maintaining muscle mass.