The role of liver function and glycogen should be included in this conversation.[1] There might be a lot more at work than just elevated blood sugar levels.
In most normal people, meaning without diabetes and other metabolism problems, the liver doesn't immediately convert sugar to fat. Rather extra sugar is converted to glycogen which can be easily accessed for energy. What happens when a runner carbo loads the night before a race? The pasta she eats is coveted to glycogen and stored in the liver not to fat.
However, when the liver storage of energy is full, it then converts the excess to fat. Think about this for a second. The glycemic index and load don't apply because most people convert excess blood sugar to a readily available energy stored in the liver as glycogen not fat.
The problem is that Americans culturally never deplete the storage of energy in the liver because of two reasons; first, Americans snack all the time and drink sugary drinks, and, second, which I don't understand, we have developed an idea that we should eat huge third meals at night.
A big dinner will completely replenish the energy stores in the liver leaving excess sugar that will be converted into fat during sleep. Perhaps, it is smarter to eat a decent breakfast that contains simple sugars which are absorbed faster into the blood stream, a big lunch which will provide energy for the rest of the day, and a small dinner to satiate hunger.
For a person who wakes up around 7am the fast should begin around 5pm in order to let the sugars deplete around bed time. There is no reason to have readily available sugars while sleeping. And then in the morning break the fast.
There is no reason to have big dinners which are ridiculous.
1. https://en.wikipedia.org/wiki/Glycogen