One thing that many people who have diabetes have benefitted from is lowering or eliminating grains, carbohydrates and sugar.
Research "wheat free". Many people don't know that wheat (or white or wholewheat bread) for instance will raise your blood sugar up by as much as a can of soda or a candy bar. This has been documented in scientific literature. Add to that a few biscuits, a slice of cake or more during the day and you have multiple spikes of insulin occuring during the day.
Also carbohydrate foods like too much fruit or root vegetables will raise insulin levels.
Gluten free foods contain many starches which also will raise insulin levels way too high so are very bad for diabetics.
Many people who have cut out grains and only had less than 50 grams of carbohydrates per day are able to get their problem under control, many are reversing all diabetic symptoms (type II). Some type 1's have been able to get off insulin (some).