5 days keto diet is not enough time to make a definite conclusion. We all have our ups and downs which last sometimes days or weeks or months. BTW, it’s well known phenomena that any novelty in your body function can be beneficial for speech. Try modulating your speech with any accent, tone, speed, even loudness and you’ll see immediate results. Alas, these effects don’t last long. The same relates to acting. There are well known actors who do not stutter while they are acting. I stutter for 75 yeas but when I deliver lectures to students (I am an adjunct professor in college) I am almost 100% fluent. Aging also helps though can’t recommend it as a cure, lol…