This is opinion, I can’t prove the conclusion. It’s based on years of considering a very large number of studies and coming to overall opinion rather than actual proof of why adult-onset diabetes is so drastically more prevalent today than in the past.
As adult-onset diabetes, as well as metabolic disorder, are so drastically more common today than previously, most likely – but not necessarily – your early stage problem isn’t genetically inevitable for you, but is caused by actions particularly with diet. (For many inaction, lack of exercise, is likely a major part of their cause, but this doesn’t sound like it applies for you.)
I believe the four principal dietary causes are, the first two being in no particular order, and using the word “abnormal” in reference to the sorts of diet man had had for many thousands of years prior to the 20th century and the high rates of development of diabetes and cardiovascular disease:
Abnormal fructose intake, including from sucrose
Abnormal linoleic acid intake (historically under 10% of fat intake, now 20-30% or more)
Abnormal relation between phytonutrient intake and carbohydrate intake. In other words, it used to be that carbohydrates came along with various beneficial substances provided by the plant. For some time, the population has had high carbohydrate intake but low intake of these materials.
Abnormal relation between protective-fatty-acid intake and linoleic acid intake. (Low DHA/EPA vs linoleic acid.)
Your carbohydrate intake sounds very reasonable; the only area where it might be problematic is if fructose is over say 25 g/day (this is not a magic figure but seems a good general guideline.) If your extra 100 g is mostly pre and during workout and the remainder mostly post workout, then this sounds very suitable already. Some do benefit over a period of time from going still lower on non-training days but this may well not be necessary for you.
On linoleic acid, the amount in your body is likely too much if over the last few years a fairly large percentage of the fat in your diet has been from vegetable oils in prepared foods; from soy, corn, safflower, sunflower etc oils that you’ve purchased yourself, from nuts other than macadamia or hazelnuts; or from chicken or pork raised with today’s animal feed. It may help, slowly over time, to cut such intake. It’s certainly historically abnormal, and leads to oxidative damage.
On the third point, at your carb intake this balance is likely not an issue, but some concentrated phytonutrients might help.
A person of course has the same genetic code throughout life, but the gene expression – how much enzymes, signaling molecules, proteins, receptors etc they make – varies according to exposure. There are many changes associated with development of diabetes and metabolic disorder; some phytonutrients act towards reversing those changes.
The fourth point is simple, more intake of wild-caught cold-water oily fish and/or a quality DHA/EPA supplement.