how much of a difference does insulin response really make in daily nutrition?

[pSb]

if you took two identical diets, same source of proteins carbs and fats with identical calorie counts, but changed one meal from oats to dextrose, what would your net difference be in a month? a year?

this is not asking in regards to PWO nutrition. more of an overall daily effect in weight gain or maintenance over a period of time.

if someone posts a lengthy scientific explanation please give cliff notes. thanks