Its not really worth the benefits. Some people will say it will slightly help you burn fat rather than any food/nutrients your taken in recently but if its true its makes such a little differnce that your just better off eaten and youll have the energy to burn off far more calories.
If you want to loose weight its as simple as eating clean and doing exercise atleast every other day.
Things like green tea, running on empty stomach, fat burning supplement are only of any use to people already at 8/9% body fat who want to get even lower.
I used to go to the gym at around 9am after only being awake half an hour or so sometimes!
I never had breakfast and i could never do much i just felt drained, so now i have something like scrambled egg beans and toast or jacket potato and tuna an hour before the gym, doesnt bloat you up and gives you an energy boost
First thing in the morning, a bit silly depending on when you had your previous evening meal.
Just before dinner, not too bad as you should have had lunch and breakfast earlier in the day.
I've done a bit of cross-country and tried to make sure that I ate no later than 1 hour before a race. As that was usually in the afternoon I'd go for a chicken salad sandwich and a couple of bananas and drink plenty of water in small amounts throughout the morning and up to 30 mins before the start.
Running on empty just made me feel drained and lacking in energy.
Personal preference really, try some trial and error.
It worked for me as a few years ago I won the Cyprus Interservices X-Country as a veteran.
Personally, i prefer to run on an empty stomach, whatever the distance, although for long distance tabbing the more scoff the better.
I think it's because i run at a fast - ish pace (well, it seems feckin fast to me!) for 5 miles and do a sub 40 minutes ..that's with 35lb of kit in a daysack btw, not bad for a 48 year old i keep telling myself.
I've just got into the habit of eating a good size bowl of pasta within 20 - 30 minutes of exercise and think if i ate before running i'd want to chuck, but that may just be a mind thing? i heard about needing fuel i.e eating, before a run but i can only say what works for me.
Maybe there's scientific proof that i'm doing it all wrong? but i feel ok with my method.....it helps that i use some good fast choons to keep my legs moving and do struggle if i run without music to pace myself. I guess a lot of it is all in the mind, but we've all known that for years.