YouTube likely has millions…tens of millions?…of weight loss videos. Here is the simplest rendering of the science suffering yo-yo dieters should digest:
In short: to lose weight, don’t eat. It’s hard, but it’s simple.
Think of your body has having a refrigerator (glucose) and a freezer (fat). The fridge is easy to access. If it’s full, excess goes into the freezer.
When drawing energy from glucose, if insulin is high and glucose runs low metabolically the body preserves by drawing down energy. To draw down fat in the freezer, you must access it.
If insulin is low, fat stores are accessed.
Simple, and hard. When habituated to it, much easier. That path is easier on ketogenic diets and fasting.