I found when I was have a daily morning coffee, it would totally wreck my speech for the day. I never really thought about it until one day I decided to cut out caffeine and refined sugars from my diet, and my fluency improved significantly. Coffee surges dopamine in the brain by binding to and blocking adenosine receptors in the brain. Adenosine is what makes you feel relaxed. Coffee gives you adrenaline, which can’t wreak havoc for a stutterer who already has a high base level of dopamine. Start a food journal and take note of what makes you stutter more throughout the day. You might find out some interesting things.