It's scientifically established and also logical that to lose weight, we must consume fewer calories
than our bodies burn on any given day.
The feeding window is the time when you consume whole foods.On a longer therm this type of eating will create calorie deficit (eating less calories
than your body burns).
To gain weight you need to eat more calories
than your body burns.
In general, the consensus is that you'll need to create a calorie surplus (i.e. consume more calories
than your body burns) in order to successfully build muscle.
This is when you consume fewer calories
than your body burns (or burn more calories than you consume, it's the same thing).
A calorie restriction (eating less
than your body burns) is the only way to lose weight and fasting can have a profound effect on your ability to stick to said calorie restriction.