Many people believe that drinking diet soda can lead to weight gain, but the science is not conclusive. Some studies suggest a link between diet soda and weight gain, while others do not. For example, research on rats has shown that artificial sweeteners might interfere with the body's ability to regulate calorie intake, potentially leading to weight gain. However, these findings are not definitive. Observational studies in humans have also shown mixed results. Some suggest that people who drink diet soda are more likely to gain weight, while others indicate no direct link. It's possible that people who are already gaining weight switch to diet soda without changing other unhealthy eating habits. Experts agree that more research is needed to understand the relationship between diet soda and weight gain fully. Meanwhile, maintaining a balanced diet and regular exercise remains the best approach to managing weight.