I do a lot of cycling these days and have been reading up quite a lot on how to fuel for exercise. Not sure how much of this is accurate, but it's the way I am leaning right now:
I do my daily morning exercise (45 mins to 1 hour on an indoor training bike) on an empty stomach - and normally keep my heart rate in the aerobic zones (although twice a week or so I'll do some high intensity interval training and push it right up to max). This trains the body to metabolise fat more effectively or so I have read - although the high intensity anaerobic work is not good for fat burning - and tends to improve carbohydrate metabolism rather than fat.
Afterwards, I'll typically have a pint of skimmed milk as a recovery drink as the protein:carb mix (approx 4:1) is meant to be almost perfect for muscle recovery. My typical BG first thing in the morning is around 5.4, after an hour exercise it's normally between 4.5 and 5.5 depending on the exertion, and 2 hours after a pint of skimmed milk it's almost exactly the same.
If I'm doing a long, heavy stint such as an 8 hour endurance ride, I'll fuel up with porridge and bananas at least an hour before the ride and then keep topping up every hour or so with carb rich foods like flapjacks, or energy bars/gels. I've never checked my BG during a long ride, but immediately afterwards it never seems to be over 8.5 or so - pretty much no matter how many carbs I have eaten. After a long heavy ride, I'll have a carb rich meal such as wholemeal pasta with plenty of cheese - aiming for the 4:1 carb
rotein ration again. 2 hours after that, my BG is normally still under 8 or so.
Long story short......I think that depending on your exercise intensity, your metabolism primarily burns more fat or carbohydrate. Lower intensity exercise is better for fat burning - and doesn't trigger an extreme of glycogen dump, whereas high intensity does, but you're also more likely to burn through the sugar - plus any that you add as fuel.
So....my thinking would be, if you are doing aerobic exercise, then do it on an empty stomach, whereas if it's anaerobic then you should fuel beforehand. Either type of exercise should be followed up by a recovery meal/drink with approx 4:1 carb
rotein ratio within 20 minutes of finishing up. In my experience, the speeded up metabolism caused by exercise will burn through the carb from the recovery meal pretty **** effectively.
This works well for me. Your mileage may vary
For the rest of my life, I follow a pretty strict low-carb diet with the only real exceptions being some home made sourdough bread once or twice a week and some basmati rice cooked in the Persian style (with a crispy crust) every couple of weeks (OK - maybe a popadom and chapati with a curry every now and again, although I now have lentil daal instead of rice with those!)
