I am taking a continuing education course on male body sculpting. The test will be based on a book written by a gentleman with an MD after his name.
The author had a recommendation for weight loss: if you work out in the morning, do not eat beforehand so you lose more fat. He states that the body has to burn fat for energy in order to fuel the workout.
This is not a good idea.
I don't pretend to be more knowledgeable than a doctor. However, after a decade of personal training, I cannot vouch for that recommendation.
I never have to wonder if my early morning clients have eaten before their workout. I have had clients turn gray, get dizzy — one person even vomited. Each time I would say, "Let me guess: you didn't eat this morning, did you?" In every instance, I got a nod of admission.
My experience has shown me the body cannot properly fuel a workout without nutrition. (There are a few exceptions to the rule, but very few.)
Even if you do manage to get through the workout, your not going to have enough intensity in the workout to get the full benefits you seek.
A study from Britain suggests there is only a difference of one-tenth of a pound between working out before breakfast or eating first. For that little a difference, don't risk illness and low energy.
Eat first: you will feel better. Even if breakfast is only a piece of toast and a banana.