some people will say depends on what exercise
some people will say jog in morn on empty stomach is very
effective
But I don't agree. Breakfast is the most important thing in the
morning. It kick starts your metabolism for the day. Your body has
already fasted since the dinner the day before (unless you eat
supper, or take a cup of milk before sleeping like me, or take
casein protein supplement like Macro_Simone). This is why breakfast
is "Break Fast".
Sure, you will lose weight, but it may quite likely be more muscle
mass than desired. Muscles are the one that help increase your
resting caloric expenditure, and by losing it, your metabolic rate
will drop, and make it harder for you to lose fats. This is another
reason why diets do not work well, especially if there's a yo-yo
effect. Each time you diet extremely, you lose both fats and
muscle. You will then need to eat less and less to maintain the
weight loss, which is clearly not desirable. Your amount of
nutrients intake would not be sufficient.