Go from a lunch time to another lunch time so you’re sleeping through most of it. Also, make sure you eat normally and don’t overcompensate when you break the fast. Fasting isn’t anything special when it comes to weight loss, it’s just a method of cutting calories. Yes, there are hormonal changes and all that other stuff, but really, it’s still about cutting calories. (And when I mean nothing special, I really mean that. You can read old Greek dialogs debating whether it’s more proper to eat one meal a day or two. The idea we need 3 or more is a modern thing).
For me, eating only one meal a day (I don’t consider it fasting until it’s several days, personally) helps me avoid taking in excess calories. You have more opportunities to mess up if you eat more frequent meals.
If you have a lot of weight to lose you’re going to need to do more than 24 hours once a week. You can start with that, since you’re new to fasting, and build up your fasting muscles. But you will need to increase those fasting hours, even if you just do it a little at a time.