Wondering what to eat to easily get through a marathon or ultra race?

Before you binge out on pasta dinners and bagel breakfasts, you might want to take a serious look at what researchers are reporting about “carbo-loading” before a marathon or long endurance event. The days of high-carb diets may be over – well, make that modified — for athletes who want to perform their best on race day, or so says the March 2013 issue of Competitor magazine. New research is suggesting that a low-carb diet may actually have benefits because it trains an athlete’s muscles to be better fat burners.

When muscles can access fat as fuel during a race, glycogen stores are spared and saved for use later down the road – this means “hitting the wall” or “bonking” can be delayed and perhaps even avoided completely. But don’t swear off pancakes just yet. Training day after day on a low-carb diet can leave a runner feeling sluggish and slow because glycogen stores never get topped off. Plus, there hasn’t been any irrefutable, one hundred percent conclusive proof that removing carbs from the diet improves endurance performance. In fact, one study at the University of Birmingham in England found that low-carb runners (41% carbs) reported more fatigue and showed reductions in performance than their high-carb counterparts (65% carbs) during intensive training runs.

Good fat-loading choices on left. Good carb-loading choices on right.

A new pre-race nutrition paradigm that combines the two ‘loading’ approaches is being recommended by experts in the sports performance field.  Here’s the plan in a nutshell. About two weeks out from an endurance event, aim to get about 65 percent of calories from fats and continue this high-fat intake for 10 days. This “hall pass” to eat fats doesn’t mean you can pig out on pizza and ding-dongs all day, or really any day. Quality fats from healthy oils, nuts, meats, avocados, whole milk, cheese, eggs, and fatty fish are what should be on the table. During this phase, your body will learn how to tap into fat stores for fuel; and, your training won’t suffer much because you’ll be tapering down anyway.

After 10 days of eating low-carb, high-fat foods, switch to a traditional “carbo-load” diet that incorporates 70 percent of calories from carbohydrates for the next three days. This ensures that your glycogen levels are as high as they can be and are raring to go on race day. Stay away from processed carbs and too much sugar. Instead, top off your tank with high-quality, healthy carbs including whole-grain pastas, breads, and rice along with plenty of fruits and veggies (but, of course, cut the fiber intake 24 hours before event).

A study conducted by the University of Cape Town in South Africa implemented this 10-day ‘fat-load’ followed by 3-day ‘carbo-load’ plan on a group of experienced cyclists. After a moderate two-hour warm-up, the athletes were able to complete a 20k time trial 4.5 percent faster following the new diet protocol. What do you think? Is it worth a try?

To recap:

• Day 14 through Day 5 before event: High-Fat, Low-Carb
• Day 4 through Day 2 before event: High-Carb, Low-Fat
• Day 1: Race!

 To give you an idea of what a “High Fat, Low Carb” and a “High Carb, Low Fat” days look like, I’ve come up with a sample menu based on an approximate 2,500 calorie diet.