With nutrition on my mind pretty much all day every day, there are plenty of things I want to write about and plenty of things I already talk and write too much about (pressure ulcers anyone? PEG feeds? BMI of 12, please just drink some Boost? No? Bueller?). Even though I’m not doing much sports nutrition at my hospital or private practice jobs right now, I hope to change that as time goes on and I get more experience. I try to stay on top of the research, which is forever ongoing and never ceases to fascinate me.
Fueling an essential part of training for endurance athletes; it’s hard enough figuring out what works for you, never mind trying to sort through all of the information out there that may or may not be useful and correct.
some fueling go-tos
One thing I’ve been hearing more about lately is not taking fuel during long efforts in order for the body to burn fat instead of the fuel (carbohydrates) you may usually take in as glycogen stores in the liver become depleted. The potential benefit of these “depletion” runs is to make the body more efficient at burning fat while you still have glycogen stores left so they last longer and therefore, you’ll have more energy for a longer time period. This sounds like a win-win, no?
Well, let’s talk about it. First of all, in order for your body to go into fat-burning mode during a long run, you need to run slow and keep your heart rate below a certain level. If you do any kind of workout or progression in a long run, your body will likely need to dip into glycogen stores. Whether you like it or not, the primary fuel of choice for hard efforts is carbohydrate (glucose!), and the more intense your run becomes, the less likely it will be for your body will burn fat.
Second, have you ever “bonked” before? Either during a run or race, it sucks ass. Bonking is when your body is out of glycogen stores and it hasn’t been fueled properly with carbohydrates, and both the brain and muscles simultaneously say, oh hell no.
bonking here, can you tell?
If you run long on no fuel, this will probably happen. It takes time for the body to adjust to becoming more efficient at fat burning, and if that’s what your goal is chances are these runs will be mentally and physically tough before any progress is made. It will also take you longer to recover since the muscles have been completely depleted of fuel.
It’s not all bad, though! When and if you do adjust to these “no fuel” runs, it could be potentially beneficial because as I said above, your body will be more efficient at burning fat before all of your glycogen stores are gone and you may feel stronger for longer.
So do I think everyone should do it? Will I do it? No! Here’s why:
- fuel is still necessary - If you’re a marathoner, you will still need fuel for the big day no matter how great your “no fuel” long runs have gone. Chances are your race day pace is faster than your training runs, most likely putting your muscles into the must have carbohydrates mode.
- practice makes perfect – If you don’t practice fueling on your long training runs, race day could turn into a hot mess. Finding out that PowerGel Orange Cream pisses your intestines off in the worst way (ahem) is not something you want to find out at mile 12 of 26.2
- recovery time increases - Recovery time is longer for un-fueled long runs, which may be a hard thing to get used to and can affect your other weekly runs
- the benefits can vary – It takes time for the body to become more efficient at this fat burning process, and it’s different for everyone. So, even if you put in the work, it may not make a noticeable difference come race day
- it’s also mental – Like I said above, mentally, un-fueled long runs are tough (your brain needs carbohydrates too!) and hard to get through. If you’re a newer runner, this may put a negative spin on training in general, which is totally unnecessary!
Even though I’m not motivated enough to try a no fuel long run – heck, I look forward to that mile XX delicious gel snack – I think this topic is pretty interesting and I’ve read about pros who have successfully done it and have become more efficient with their fueling. That said, it’s important to note that even if you do reach this “efficiency” point when it comes to fat burning, you cannot expect to run and race without fuel. Your body will be more efficient at using what it’s got, but glycogen stores will still run out and you can’t rely solely on fat for energy.
When it comes to fueling, the ~30-60g of carbohydrate, repleting electrolytes and hydrating with 6-12 ounces of sports drink or water every 45-60 minutes of running is the golden rule. My personal plan is slightly different, and I usually start taking in carbohydrates around 90 minutes into a training run and about an hour into a marathon, mostly gels because I suck at trying to chew and run at the same time. But everyone is different! Practice makes perfect, so using your long runs to figure out what works is key.
Thoughts on fueling (or not fueling) during long runs? Have you ever tried a “depletion” run? Favorite fuel of choice? I am really liking Hammer Gels lately!