Stop Overeating Question about Diet Sodas & Zero Calorie Arizona Arnold Palmers

I have just completed my first week of No Sugar No Flour, and I’m excited I’ve lost 4 lbs. I’m 5’8″ tall & currently weigh 137 lbs. I’d like to get down to 130 lbs. I don’t drink diet soda, however now that I can’t have my frozen Icee when I go to the movies, would it be okay to substitute a diet soda? I also love the Arizona Arnold Palmer Zero Calorie Half Ice Team Half Lemonade. Will that affect my insulin levels, and is it okay to include in my protocol in addition to water?

Thank you.