What is good to eat to sustain high blood sugar ?

Hi, I've noticed a lot of posts regarding LC and Keto? to prevent high blood sugar. I work quite a physically demanding job, being on my feet for up to 10 hours a day, usually I turn my basal down to 20% during this time and eat chocolate/peanut bars, ham sandwich (Brown bread), sweet potato cakes and a banana, drinking nothing but water. Is there anyone out there who can help with advice about what to eat/drink when exercising for long periods of time with type 1 diabetes (preferably without gaining a few lbs)? I'm about to Google the answer, but I like first hand information from people on the sub. Thanks.