<<I came across the following quote in the "Medical Briefing" by Dr. Thomas
Stuttaford:
"..insulin resistance is much higher in the morning than later in the day."
This means that carbohydrates eaten at breakfast cause a greater insulin
spike,
than the same amount of carbs eaten later in the day. The implication is
that a carb-free breakfast, with any carbs postponed to the later meals, is
best both for health and weight loss>>

Cortisol levels are higher in the morning because both exercise and sleep
increase cortisol release from the adrenals.  Higher cortisol has the effect
of mildly increasing insulin resistance.

However, another explanation supports your assertion that carbs eaten at
breakfast cause a greater insulin spike, but not in direct terms of insulin
resistance.

When insulin is first released into the blood, it bonds to insulin receptors
on your cells.  Although insulin is cleared out of your bloodstream within
about 2 hours after eating, it continues its glucose transport work into
cells for about 8 hours (from the time of the original meal).  Since you
haven't eaten for the last eight hours first thing in the morning, there is
little bonded insulin carrying out its delayed effects.

As a result, breakfast will generally raise your blood sugar level much
higher than the identical meal later in the day.  This, in turn, will cause
a corresponding exaggerated release of insulin, which can manifest as low
blood sugar three to four hours after the original meal and preferential
storage of dietary calories as fat.

In addition to limiting carbs (but not necessarily excluding completely),
one would want to limit their total caloric intake (which can also have the
effect of raising blood sugar levels).

Rob