Its all personal preference. You can eat anything you want as long as you inject accordingly. But i find more injections, and higher doses (for me) lead to a greater variability in my readings and that lack of predictability leads to highs and lows i'd rather not have.
Consistency is your friend.
I have found its much easier to live with a diet that is lower carb (i try not to eat more then 60g of carbs in a meal). The lower the carbs the less insulin is needed and that usually means (at least for me) the chances of being high or low after a meal have significantly decreased.
Also, i find that having a fairly repeatable schedule works best. I try to eat the same foods at the same times (i have a day set for workdays, gym days, and weekends lol). This way once you nail down your basal and bolus rates your much more likely to have similar readings each day, and thus many more 'good' days.
I also make sure i write down everything i eat, when i eat it, my BG levels, and my injection doses in a book i carry around, so when i have to eat out or something new i can look back in the book to the last time i ate it and see how i handled that situation and adjust accordingly. So far it works fantastically.
As a preference I am a vegetarian as well.. but I have been for most of my life, years and years before i was diagnosed so that's neither here nor there lol