Men with the highest sugar intake (more than 67g a day) had a 23% increased chance of suffering from depression and anxiety after five years than those who consumed the lowest levels of sugar (less than 39.5g a day). While this is an interesting association and the study does account or some other lifestyle factors, it still does not establish causation. Other studies have shown that men that drank a refined sugar beverage for 3 weeks had a 100% increase in biomarkers for inflammation. Inflammation has been shown to play a causal role in depression. Check out my short animated video that explains how inflammation has been shown to play a causal role in depression. Video: https://www.youtube.com/watch?v=fqyjVoZ4XYg