The only way that people with blood sugar issues, metabolic syndrome, pre-diabetes and diabetes can make huge progress is by cutting the carbs way down. Limiting carbs to under 50 grams/day, maybe even to 20 grams/day produces results.
Anyone who thinks low-fat diets work needs to take a look at the high percentage of people who gain all the weight back after going on a low-fat diet. The reason is that these diets are not sustainable in the long run.
I have been eating a ketogenic diet for over five years now and all my markers for health have been excellent: blood sugar, triglycerides, HDL, inflammation markers, even my thyroid levels have improved from being borderline low to being in the low normal.
Most important, my energy level and activity level are much higher, my muscle mass has increased, my body fat is at 18% while exercising only a very moderate 1 hour/day (mix of strength training/hiking/slow jogging. We eat the tastiest food on the planet, homegrown veggies and berries, and animal products from pasture-raised animals, in particular duck eggs and beef and yogurt every day.
It is now easy go gain muscle even after a break from exercise.
Another great benefit is that my body is naturally happy eating only twice a day and I often skip meals (intermittent fasting) without even noticing. This saves money,making up for the higher cost of quality animal-based proteins and fats and saves time with meal preparations as well.
There is more and more research showing the superiority of a ketogenic diet over a low-fat diet and I have every reason to believe that this will continue.
If your body has any trouble dealing with high blood sugar don't wait until it's too late. Reduce the amount of foods that will turn into sugar in your body. That is all carbohydrates, from sugar and from starch.