Was naughty yesterday and had hot chips and a pluto pup. Reading was 8.0.!

Just wondering...last time I went to my check up, the diabetes educator said Im doing well but just re-think my diet. So, even though I know I am slipping up by eating 'bad' foods and I get the high reading - will they put me on insulin? Or do they put u on insulin if you had low GI and get high readings?