Initially, your workouts will feel a lot harder than before, but quite quickly your body will become more efficient as your muscles learn to use less glycogen and burn fat for fuel instead.
Once you get used to it, you might find there’s no going back. I’ve spent the past four years training fasted – and three of those were as a competitive sprinter, competing nationally. I hate the feeling of training with food in my stomach; I feel heavy, bloated and lethargic.
That doesn’t mean that I always exercise fasted, however. I still carb-load before a race, to maximise my performance on the day.
It’s also important to note that if you’re going to do a particularly strenuous workout, you should eat some carbs beforehand. That way, you’ll prevent your blood sugar levels from dropping too low, which can cause dizziness and nausea.
So should I avoid carbs completely?
While I recommend exercising fasted, that doesn’t mean I think you should always stay off the carbs. Indeed, issues can arise with fasted training when combined with very low carb diets. The problem here is that you can decrease the body’s ability to utilise carbohydrate. Ultimately, the goal should be ‘metabolic flexibility’ – that is, to prime the body to use both carbs and fat as and when required. Two energy stores are better than one.
Be strategic with your carbohydrate intake. Eat more on your training days and less on your rest days.
Can I have anything before a workout?
Yes – to an extent. I like to have a strong green tea or black coffee right before my workout. This spikes my metabolism, helping me to burn those fatty acids even quicker once I start working out.
I should also say that you should always drink water – before, during, and after a workout.