In this episode of Ask Coach Parry we chat about how the body uses fat for energy as opposed to carbohydrates. Patrick Kongsilp submitted his question, and it says:

“Hi Coach.  So I’ve come to the realisation that I’ve been too dependent on carbohydrates for the past few years to fuel my training runs.  My weight remains steady at 72.5 kg’s, yet high for my height.  Despite the fact that my weekly mileage has increased since August, from 56 km per week to 80 km per week.”

He suspects that during the majority of his training runs his body was consuming carbohydrates and not properly trained to utilise fat.  Hence, he was basically wasting energy carrying dead weight fat, which was slowing him down.

His marathon PB was a 3:08”10 back in 2004, so ten years ago, where he weighed 64kg.  It was about 8 kg lighter than he is now.  The best he’s been able to do since then was a 3:19 back in 2012.

He’s got a Comrades Marathon PB of 8:52 in 2012 as well.  Looking back, he thinks he was eating a lot less carbohydrate, and his body was trained to utilise fat.

Recently he’s cut down on his carbohydrate intake to normal levels, and stopped using energy gels during his training runs, although his weight is slowly decreasing.  He’s now down to 70.8.  He’s been able to do long runs at a much slower pace.

Is this normal, as he’s training his body to rely more on fats to power his runs, as opposed to carbohydrate?  Is his theory sound?

Brad Brown: In this episode of Ask Coach Parry we chat about how the body uses fat for energy as opposed to carbohydrates. Patrick Kongsilp submitted his question, and it says:

“Hi Coach.  So I’ve come to the realisation that I’ve been too dependent on carbohydrates for the past few years to fuel my training runs.  My weight remains steady at 72.5 kg’s, yet high for my height.  Despite the fact that my weekly mileage has increased since August, from 56 km per week to 80 km per week.”

He suspects that during the majority of his training runs his body was consuming carbohydrates and not properly trained to utilise fat.  Hence, he was basically wasting energy carrying dead weight fat, which was slowing him down.

His marathon PB was a 3:08”10 back in 2004, so ten years ago, where he weighed 64kg.  It was about 8 kg lighter than he is now.  The best he’s been able to do since then was a 3:19 back in 2012.

He’s got a Comrades Marathon PB of 8:52 in 2012 as well.  Looking back, he thinks he was eating a lot less carbohydrate, and his body was trained to utilise fat.

Recently he’s cut down on his carbohydrate intake to normal levels, and stopped using energy gels during his training runs, although his weight is slowly decreasing.  He’s now down to 70.8.  He’s been able to do long runs at a much slower pace.

Is this normal, as he’s training his body to rely more on fats to power his runs, as opposed to carbohydrate?  Is his theory sound?

Lindsey Parry:  Look there’s some sense in what he’s saying. But what people often fail to realise is that our body uses fats and carbohydrates.

I’m not going to complicate it more than that.  But it uses those two things interchangeably when producing energy.  We tend to use more carbohydrates when we exercise at higher intensities, but we tend to still continue to burn the same amount of fat.

Do we burn more fats or more carbohydrates on long runs?

So, we get to a point where at certain intensity we’re burning a certain amount of fat, and when we go above that, we’ll continue to burn that amount of fat, but we need more carbohydrates, okay.

It is true that by consuming heaps and heaps of carbohydrates you will promote the use of carbohydrates a little bit above fats.  But for me, what it really boils down to is making sure that you are doing your training at the correct intensity.

So he’s already talking there about running slower, okay.  So by running slower he’s going to burn more fat, okay.  But he’s also going to be at a low risk for injury, and he’s also going to be able to run for a longer period of time.

So, in a very simple equation, if energy in is less than energy out, you should be losing weight.  So for me the problem has probably got less to do with the fact that he was taking too much carbohydrates during exercise, and probably more to do with the fact that there’s too much processed carbohydrates or hidden sugars in his normal diet.

Okay, and I’ve answered this a few times, particularly in response to questions on Tim Noakes’ stuff, where Prof. Noakes is 200% on the money, is if you actually take note of what you’re putting into your body, anything in a box, in a can, in a bottle, in a jar, your so-called healthy Woolworths meals, bread, if you look at these things, all of them have got a high sugar content.

And sugar is empty calories. I would, take a step back, and I would look at how much sugar I’m having throughout the day, and worry a little bit less about the amount of sugar that I’m taking during my long runs.

Having said that, we train on very few carbohydrates while we’re exercising, and, I’m not actually advocating that as good or bad.  It’s situational.

I don’t, I would never carry gels with me while I’m on a training run, purely because I don’t want to have gels every day when I’m training, or every long run that I’m training, every race that I do through the year.  It won’t be long before there’s not a gel in the country that I refuse to eat, because you will just get sick of them.

So I take gels often enough that I know that they’re not going to upset my stomach come race day, and then what we do is we run petrol station to petrol station.

And if you do that, sometimes you have water, sometimes we’ll share a Coke, but in doing that without actually actively stopping yourself from eating sugar, you’re also probably never going to completely run out of energy. But you’re probably not going to overdo it on the day that you’re training either.