Yup... I'd give it some time. Remember that your liver also puts out sugar... it may even be that by starving yourself you are encouraging your liver to put out extra... hence your high FBG.
Are you testing after meals or only on waking?
From everything I have read, eating too little will do you no favours... your body goes into "famine" mode, using food very efficiently and storing any excess as fat.
Moderation in everything... including moderation itself
