"Breakfast is the most important meal of the day", they used to say.
That is one of many dogmas that don't stand any longer.
The notion was based on studies indicating that people who skip breakfast are more prone to resorting to snackfoods for lunch. Though that still may hold truth, far more convincing evidence has emerged this past decade. Thousands of studies have shown that temporary (or intermittent) fasting has great health benefits, due to the cellular effects of autophagy.

Our body can only utilise nutrients and energy by oxidizing them. For this we need oxygen from the air that we breath. Widely viewed as 'harmful compounds', oxygen radicals used to free up energy could not be more essential. The 'bad' side of these essential radicals stems from the fact that in the process of fulfilling their role, they cause collateral damage. Though reigned in by anti-oxidants, these side effects cannot be prevented. Every single second, collateral damaged is caused by the utilisation of oxygen. Utterly unavoidable. That collateral damage is done to the environment in which that oxygen is utilized; in our cells. All our cells are subject to collateral damage caused by essential oxygen radicals. As a result organelles ('cell-organs') are increasingly damaged on a daily basis. Eventually, the accumulation of the resulting 'garbage' hinders normal cell functioning, which results in cell death; 'apoptosis'.
Autophagy is an alternative route for apoptosis. Whereas apoptosis ends in a cell being broken down entirely, autophagy only clears out the garbage, extending the life span of that cell. Imagine a house with a broken window and a dysfunctioning door. In apoptosis, the house is broken down to the ground because of the broken window and dysfunctional door. In autophagy, the door and the window are chopped in pieces and utilized for energy, and a new door and window are created to replace the old ones. So, the house is fixed instead of replaced. Analogy aside, the cell is repaired instead of replaced entirely.

What difference does that make?
We are mortal because each type of cell may be replicated only a fixed number of times. Once we reached that final number, its done. If that happens in your heart first, you will die of heart failure. If it happens in your liver first, you will die of liver failure. And so on.
Autophagy extends the lifespan of cells by cleaning up the mess inside. And when cells live longer, you live longer. This theory has been supported by a great number of experiments in various species. It works in every specie, and in each individual.

What does this have to do with skipping breakfast?
If you do not consume any energy at all during the entire morning, you will create a lack of energy in many cells, evoking autophagy.
Of course you need to compensate for this lack of energy in the morning by consuming more energy later. As a result, skipping breakfast causes a shift in energy intake, resulting in a greater metabolic phase during sleep, which is better for muscle growth.