Like a lot of folks, my favorite way to spontaneously fast is if I'm not hungry in the morning - just taking it a few more hours before eating.
But I am a very faithful morning toothbrusher and have started to wonder if my seemingly benign minty sweet toothpaste could be screwing with my physiology and thwarting my best intentions with fasting. So basically this spawned three questions:
Is that 30 sec.-1 min. hit of minty sweet (which is spat back into the sink) enough to mess with the ketosis and steady low blood sugar that I'd have first thing in the morning?
If you think so, would chewing a mint leaf (or something minty but not sweet) be a viable alternative so I don't have to wander around with skunk breath until my first meal of the day? Or do you have other alternatives to suggest?
Anybody actually observed this for themselves and have any n=1 observations to share about whether toothbrushing/toothpaste and intermittent fasting don't mix?
Brushing with even the sweetest of toothpastes has never interrupted ketosis for me, as per ketostix results.
Also, I don't believe a bit of insulin would push you out of ketosis (assuming that toothpaste would raise your insulin more than a microscopic amount). In fact, can't exogenous insulin put you INTO ketosis?
Even if your body produced an insulin response to the presence of a sweet taste in the mouth (some clinical evidence suggests this is possible, but does not necessarily happen), there's no way you would interrupt the actual energy pathways that have been mobilized to supply your needs.
In other words... if you are fasting for no more than 16-18 hours, your energy needs are being met by stored glycogen (taken from the liver into the blood for the brain and used in the muscles for movement) and by fatty acids mobilized from the adipose tissue (for the muscles).