Thanks for tagging me @sassy1
Erm, yes the more I learn about the role of carbs and insulin, the more I keep my carb intake down!
I think that there are three main culprits for weight gain that you can influence (ignoring genetics which you're rather stuck with): insulin, inflammation and stress (and possibly gut bacteria, plus a host of minor players too, such as protein intake, vitamin and mineral imbalances).
Insulin is the fat storage hormone so high insulin means high fat. As carbs drive insulin, keeping carbs down keeps insulin down. Insulin resistance raises insulin levels, and is driven by high carb intake, fructose intake (..and table sugar is half fructose) and also falling hormone levels with age. The older you are, the less carbs you can tolerate
Inflammation may also be triggered by high blood sugar (i.e., carbs), but also such things as fructose intake, industrial seed oils (i.e., vegetable oils that are extracted by chemical/heat as opposed to cold-pressing), trans-fats (not only in margarines and hydrogenated fats but also industrial seed oils), food intolerances (gluten, dairy, other components of wheat, MSG etc etc), environmental pollution and more.
Stress can be due to work/home stresses but also over-exercising, poor sleep, too much fasting, inflammation, and causes raised cortisol which messes up insulin, appetite, sex hormones, thyroid hormones, sleep patterns etc etc.
And all of these factors (and more) interact with one another.
So the answer to the question on how much you need to restrict carbs really depends on your personal situation and how you choose to fast (fasting lowers insulin more than low carbing but increases stress so you need to find a balance), what you eat apart from carbs. You need to experiment to find your best balance of fasting, carb intake, meditation, exercise, protein intake, and general non-fast day food. It can take a while...I'm still working on mine nearly 4 years after starting intermittent fasting!