Today's typical cut off for beginning diabetes is 120 fasting...
And typically doctors will take several tests before evaluating that.

A1C is not always about weight it is about age, and spiking sugars after eating large meals, or alot sugar.

By eating smaller meals, you get fewer spikes. Also avoiding sugar is a good idea. But complex carbs are ok in moderation.

I find peas, soy, nuts, black beans all provide carbs but very slowly to the body.

If you skip meals entirely, your liver will kick in when sugars get low and as we age this tends to overshoot and read higher on fasting.

Much of insulin resistance involves low sugars most of the day, and until you get pancreatic burn out, then the fastings will go up.

In the not so distant past 140 was the cut off for fastings.

If you have a glucometer you can test yourself during the day, and see how certain foods impact you.
And be aware that certain testing strips use different technologies. One Touch can give false highs when uric acid is elevated in the body, or one is using alot of aspirin.
FreeStyle uses another system that reads ALL --ose sugars (not just glucose) as elevated. So false highs can occur if you consume carbs with maltose, ribose, or other sugars ending in -ose.

Infection, and activity will raise blood sugar at times also.

The home glucometers are also not that accurate and + or - 10pts is always possible. There is a control solution made to test your meter and it is a good idea to use it every 3-6months to see how the meter is working.

Also any kind of severe stress will raise blood sugar. Chronic pain, fear, trauma, etc.