What's the deal with Fat Loading and Carb Loading?

Apologies to my non-marathon-running readers and friends, because this space is going to be monopolized for the next couple of weeks with posts on strategies for the couple of weeks before the marathon.

And they’re really big weeks!

We marathon runners (and half marathon runners, too) have been training for months, but now, we’re cutting waaaaaaay back on our mileage to rest and restore our bodies after all those pounding, runs. Sadly, that means we lose the benefit of the powerful endorphins we’ve been releasing during tough workouts, and we need those feel-good fuzzies more than ever because the impending race is weighing heavy on our minds and our nerves. Speaking of heavy, one of the biggest concerns for runners during this time is weight gain. For months we’ve been feeding ourselves to fuel intense runs, and now we’re not burning calories at the same level. Try and tell that to our appetites! And then we’re supposed to carb load carefully so as not to put on weight? It’s enough to push me—I mean, someone—over the edge!

But fear not.

In the next couple of posts, I’ll break down the carb load into easy to understand concepts.

Simply put, carb loading involves eating lots of carbohydrate-rich foods before an endurance event to load up your muscles with glycogen (aka stored carbohydrates). We can only store a small amount of carbs in our muscles—90 minutes to two hours at a hard effort of exercise. We have hours of fat to burn, but using fat for fuel is far less efficient than glycogen, so we need to maximize the carbs stored before we hit the start line, or we risk a very painful finish (click for a story on a particularly painful run I had last year).

For my half marathoners: Carb loading is only effective for events lasting more than two hours. Most half-marathoners don’t need to undertake a carb-loading regiment of several days, though they definitely benefit from enjoying carb-rich foods the day before their race and in their evening meal the night before the night before the event (that wasn’t a typo: that all important carb-filled dinner happens two days before the half marathon!).

The two-phased carb load for the full marathon is a widely accepted practice (Writer/Athlete/Coach/Nutritionist extraordinaire Matt Fitzgerald has written extensively on this topic and informs my process considerably):

Step 1 is adapting a low-carb, high-fat diet of about 65% fat for several days—up to 10 if you can manage it. Your body adapts to burning fat for fuel during this phase, especially during the short workouts you’ll be undertaking without the benefit of carbohydrates.

Step 2 is the carb load, a diet of 70% or greater carbohydrates for about three days to fill up then top off your bodies carbohydrate stores.

Marathoners can opt to skip fat loading, but they tremendously benefit from a multi-day carb load. If a marathon runner waits until the day before the race to carb load, it’s already too late! Most of us need more than a day to fill those stores. 

I’ve heard quite a few questions about how much more we should be eating to carb load. That’s actually a bit of a misconception. The carb load doesn’t necessarily require us to eat lots more food—don’t forget that our bodies can only store a relatively small amount of carbohydrate. If you over do it by forcing down significantly more calories than you need, you could be carrying extra poundage to your 26.2 miler.

Carb loading is more about shifting the proportions on your plate.

Allow me to illustrate what a healthy everyday dinner plate looks like:


Should a runner opt to try the fat load (again not a requirement for every marathoner), the plate shifts to more fat, a regular sized portion of protein, and a small amount of starch vegetable or whole grain.



And for the carb load (my personal favorite illustration!), the shift is toward a larger serving of carbohydrate rich food with smaller amounts of protein and fat.

The easiest way to jump into the carb and fat load is to think of the meals and snacks you already like and to make simple adjustments to proportions and ingredients. In my next post, I’ll share practical easy swaps you can make to meet the nutrition requirements of race week.

Need help developing a custom dietary plan for your race week? Let's talk: lauren@live-full.com

The Accidental 21.7 Miler and Tips for Carb Loading

Last September, while training to run the Richmond Marathon, my husband John and I rewarded ourselves with a desperately needed long weekend at Rehoboth Beach. We chose a weekend where our training plan had relatively low mileage, so we could kick back and relax a bit.

I glanced over a few maps and meticulously wrote up a route sheet that would give us about 15-16 miles around the beach and through a state park. We got a late start—hey, 15 miles is a short jaunt after tackling 20 miles the Saturday before!—and the sun was high in the sky when we headed out. I loaded up my fuel belt with a sports gel and a 12-ounce water bottle.

We ran toward the beach along the Coastal Highway, up the boardwalk and north toward Henlopen National Park, and a few miles later, we were hopelessly lost. I mean hopelessly. We were wading through waste-high weeds, getting eaten alive by bugs the size of my fist (I have small fists, but still!), running to the tops of hills to see if we could see anything familiar, zig-zagging and U-turning with no idea whether we were headed in the right direction. 


I believe this map very closely represents the actual route we took.


We found ourselves on trails, on sand, in a campsite that was definitely featured in a horror movie. We saw animal skulls. We talked to grounds-keepers in a trailer park who said “Whoa, how the heck did you get here from there?” My water was long gone and my gel was ancient history about 14 miles in, as we started making over/under bets on how many total miles we would end up running before we saw our B-and-B again.

As we finally made it back to proper roads with names we recognized, it happened. I bonked.

If you’ve ever trained for a marathon, you know what “bonking” is all too well. Marathoners train for months to build up their physical stamina to avoid a bonk. But no matter how well-trained you are, if you don’t fuel properly, a bonk is imminent. For the un-initiated, bonking is when well into a race, typically 2-3 hours in, the body runs out of stored carbohydrate, and it feels like you have literally been slammed into a wall. Your body realizes it’s about to run our of juice, and it directs all remaining stored carbohydrate to your brain and away from the rest of your body.

As I experienced on this run, not only do your legs feel like lead, you become confused and emotional. Your head throbs. You want to lie down. One may even, hypothetically, yell at one’s husband “Where the hell are we?” and “Oh my lord, I’m going to die in Rehoboth Beach!”

We hadn’t prepared for a 20-plus mile run. We hadn’t eaten well the day before, and we didn’t bring enough fuel to sustain us—not by a long shot. When events like this happen, I like to think that I can at least learn something from them. I would like to share what I learned with you:

I never, EVER want to experience a bonk in an actual race!

A bad training run is one thing, but I would hate to go through this sort of experience on race day—and I’d hate for it to happen to you, too! For those of you getting ready for a spring marathon, don’t put yourself at risk for a really lousy day. May I suggest…

•  Three days out from your event, begin carb loading (don’t wait till the day before your race to carb load—it will be too late). Aim for 70-90% of your calories from carbohydrates, eating small snacks frequently to top of the tank

•  During the carb load, if you can tolerate it, enjoy fresh fruit—including bananas, grapes, fresh dates—and dried fruit for snacks.

•  Avoid high fat snacks like nuts (which are a wonderful snack any other time of the year), since they won’t add to your carb stores and they will crowd out foods that will

•  Enjoy lots of starchy vegetables, like white potatoes, sweet potatoes, corn (making sure not to cook them in oil or heavy creamy sauces)

•  Enjoy juice and smoothies in small amounts—look for 100% real juice, avoid sugar-free options like the plague

•  Bread and pasta made with white flour is fine during these few days of carb loading

•  Avoid junk food like chips and cakes and fried foods—they’re not helpful fuel

•  When you hit your race course, don’t start out too fast—you’ve got to conserve your stored carbohydrate even if your stores are well topped off

•  Never assume that you’ll have your fueling needs met on the course. Bring the gels or “Gu” you have practiced with to your event so you can replenish carbohydrates during your race.

Looking for more one-on-one support? Shoot me an email at lauren@live-full.com or request a consult!

Carbo Loading: Fueling for your Fall Marathon (or Half!) Part 3 of 3

What do you think of when you hear the phrase “carbo loading?” You might have the image of a runner going to a nice restaurant the night before the race to eat a massive plate of pasta, two or three rolls and a dessert on top. Some runners may follow that stereotype. Many don’t, and frankly, most probably shouldn’t!

Do runners have to carb load for every race?

Actually, no. If you’re running in event that will take you LESS than 2 hours to complete, won’t get significant benefit from carbo loading.

So why would a longer-distance runner need to carbo load?

I explained in the first part of this blog series that stored carbohydrates are a very important fuel for the endurance athlete. You can access the fuel quickly, and it’s the primary fuel for hard efforts. In the 2-3 days leading up to your race, your goal is to continually top off your carbohydrate stores so that when you arrive on the start line, your stores are completely full. That means you should NOT wait till the day before your race to start thinking about carb loading!

In the 3 days before your race, you should be consuming somewhere between 70-90% of your calories from carbohydrates. That doesn’t mean that you should be eating more food over all, it just means that you should limit high fat and high protein foods and replace those foods with carbohydrates. It’s also important to remember that any foods you eat during this time should be foods that you are very familiar with and that you have eaten during your training—digestive surprises are not welcome! Some examples of how to easily incorporate more carbs into your day:

  • Do you like to snack on almonds, sunflower kernels or other seeds & nuts? Normally that’s a great option, but during this period, swap out those healthy fats for a banana or another fruit, or try crackers or pita bread
  • Do you like to put olive oil or pesto on your pasta? Again, not bad choices most of the time, but during this period, swap them out for sauces that are higher in carbs, like a tomato sauce. You could use a smaller-than-usual amount of sauce and just increase the amount of starch on your place to make up for the lost calories
  • Love a big portion of protein? Not during this time. Eat a smaller portion of protein and fill the empty space on your plate with more rice, pasta or other whole grains
  • Add starchy vegetables that you are comfortable eating to your menus, including carrots, baked potatoes, yams, squash, etc
  • Drink some of your carbohydrates in smoothies and juice using organic fruits and vegetables
  • White flour is okay in the 2-3 days before the race as long as you can tolerate it. Your body is going to snatch up those simple sugars quickly on race day.

Your biggest meal should be two days before the event and not the night before. You don’t want to start your race with a heavy feeling in your gut, and you most definitely don’t want to have to make pit stops along the course to…ahem…unload last night’s big dinner.

By the way, during these couple of days, it’s pretty broadly recommended that you should avoid alcohol (for so many reasons, I’m not even going to go into it—just avoid it!). And though I am a big fiber fan, don’t overdo it during this time.

By the time your race day arrives, you’ve had lots of practice eating breakfast before your long run. You know what works well and what doesn’t. You’ve also tested out gels and sports drinks, so you know their impact on your performance and on your gut. Don’t try anything new on race day. I cannot repeat this enough…NOTHING NEW ON RACEDAY! A few suggestions…

  • If your race is many hours after your breakfast, plan to take your breakfast on the road with you
  • 1-3 hours before the start, hydrate with 12-16 oz of water, sports drink or juice
  • Bring your own gels and/or sports drink to the event. Never expect that your fuel needs will be met by the event
  • If you can tolerate it, take a drink at every water stop, whether it’s a sip or a full cup of water or sports drink

During your race, your body will take somewhere around 30 minutes to assimilate any calories you introduce. That means you should be replenishing with carbohydrates before you feel like you need them. If you’re completely zonked at mile 24, it’s too late to get much benefit from downing a gel then. Don’t wait! Somewhere between 30 – 60 or more carbs per hour will go a long way toward pushing back the wall.

Got a question or need some more guidance? Leave me a message in the comments or get in touch through this website. Good luck, runners!! I can’t wait to hear the triumphant racing stories from running pals and clients!