I didn't get my first dental cavity until I was 40 years old (diagnosed exactly two months to the day after my 40th birthday!) because I am so obsessive about personal health and hygiene. I do brush my teeth as soon as I wake up for a few reasons. It feels better to have minty fresh breath, that big ol' mintastic smooch I lay on the boyfriend lets him know I'm going for my morning jog (I do 6-8 miles every morning, depending on which route I run that day) so he knows if I'm not back by a certain time something has happened and he needs to call some of the other menfolk - or the police - and go looking for me and finally because I don't eat until after my jog and all of my animals have been fed and I have showered. (I also shower before I go to sleep. Dirty people are rather disgusting in my view.) So I may wake up around 2 am or so most days, but I won't actually eat my first meal until around 6 or 7 am. This means the mint toothpaste/nutella and croissant flavor clash won't be an issue.
I also brush my teeth every time I eat. Not just after a meal. EVERY time I eat something. I'm pretty sure the only reason I got that cavity (and the one right after it) is because I started taking cream and sugar in my coffee and don't brush after each cup of coffee. I drink coffee constantly, from the time I eat breakfast up until finishing my last cup as I'm heading into the bathroom to brush so I can go to sleep, so brushing after each cup would be difficult for me to do. My boyfriend says I should just get off the sugar and cream in each cup of coffee and start treating those as dessert items or special treats like I used to do and just take my coffee black. However, as I've gotten older, my tolerance for bitter flavors has gone down as my coffee consumption has gone up, so I don't see that happening any time soon. Maybe some enterprising young person out there can invent and then market a coffee flavored toothpaste. I'd buy your first case - guaranteed!
I really would buy a good coffee flavored toothpaste, btw.