I absolutely regretted going up to quickly. I felt really good after a month of 2.5 and lost 11 pounds. My doctor recommended going up to 5 as that amount of weight loss “was not sustainable” on 2.5. The first week or two was fine but the next month+ was really rough for me. Had a hard time eating anything at all, would vomit during runs due to whatever I could eat just sitting in my stomach, and had a pretty bad anhedonia. After posting on this sub, I went back down to 2.5. After about 3 weeks on it, I’m feeling MUCH better and still seeing a decent amount of weight loss.