I came across this on the No Meat Athlete website the other day when looking for non sugar based fuel to run on for during my long runs:
Here’s an excerpt from it:
How You Can Train Yourself to Burn Fat for Fuel
It’s possible to change the way you run and eat so that your body learns to run on fat from the very start of your run, rather than waiting until sugar supplies are depleted, shifting to fat only as a last resort. Pretty exciting stuff, huh?
Hold it right there. Before you swear off sugar and start packing your old energy gels in your kids’ lunches, remember: This is a gradual process. If you currently take in a lot of sugar before and during your runs and you suddenly stop supplying it to your body, you’ll bonk, and it’ll be dangerous. Introduce these concepts slowly and gradually, and always carry a few gels with you for emergencies.
With that out of the way, let’s get into the nuts and bolts of what you can do to start burning fat.
First, note that we’re only talking about the long, slow run. Your body starts sugar-burning as your exercise intensity crosses the lactate threshold. (A good indicator of when this happens is when it becomes difficult to carry on a conversation, or when your mouth drops open to start taking in air while you run.) You can gradually increase the level of intensity at which you cross the threshold, so that you can eventually run faster while staying in a fat-burning state. For speedwork and hill workouts, your body will still rely on sugar, and that’s fine, since they’re short, and sugar is great for hard, short runs.
Extend your warmup period. If you’re standing still and you suddenly bolt off running, your physiology changes. Your body senses something is up (perhaps you’re being chased by bears and zombies?) and starts burning the sugar fires, since sugar is great for short bursts of energy. But that’s exactly what you don’t want to happen on your long run.
So warm up extremely slowly. Walk for the first few minutes. Then start running so slow that you have to hide your face when you pass people you know. Relax everything and enjoy it. Over the course of 10 or 15 minutes, build up to your long-run speed. Speaking of which…
Run slow! You want to stay below your lactate threshold for as long as possible, so your body can get used to burning fat for fuel. So go really slow. If you use a heart rate monitor, stay at 60 to 70 percent of your max. Make sure you easily carry on a conversation while you run. Your goal is to do this enough that your threshold increases, i.e., you can run faster yet still stay in this aerobic, fat-burning zone.
Practice running in a carbohydrate-depleted state. Running coach Greg McMillan has a great article about depriving your body of carbs so that it learns to burn fat. This means restricting sugar intake both before and during your long runs.
Stu Mittleman personally told me that he would never even eat a banana while he was running, and instead carries raw almonds and vegetable purees with him. He recommends fatty, alkalizing foods and a little protein. So besides nuts, you might also try nut butters on vegetables, or perhaps avocados and even oils if you can stand taking them straight.
Again, be careful with this. I’ve found that it’s a slow process to transition to completely carb-free runs. I’m at the stage now where I’ve eliminated a lot of the sugar from my long-run routine, but I still eat some non-sugary carbohydrates. This is why I’m a big fan of pinole, and also things like whole-wheat pitas with hummus, or a wheat bagel with almond butter or peanut butter, though I’ve tried to limit gluten recently. Keep in mind that this is still very much a transition phase, as complex carbs are ultimately converted into sugar before they’re used for energy.
Interesting stuff! I think I’ll be trying out some of the recipes.