Fasting glucose can be low on high-carbohydrate diets (fruit, honey) but elevated above 100 on keto or carnivore diets due to physiological insulin resistance and gluconeogenesis.

“my fasting glucose is 89 remember that I eat upwards of 300 grams of carbohydrates primarily in the form of fruit and honey every day and My fasting glucose is still very low um often when I get a fasting glucose it's even lower than that previous blood work it's been lower 80s sometimes High 70 s this one was 89 but from my carnivore days when I was strictly carnivore and keto My fasting blood glucose was above 100 and I've seen other people in the keto and carnivore space when they do share their blood work note that their fasting glucose is often above 100 this is physiologic insulin resistance and the fact that your body is always making some glucose probably through gluconeogenesis when you are not giving your body carbohydrates”