Runners are always looking for an edge. Heidi Strickler, Seattle-based Registered Dietitian, Certified Specialist in Sports Dietetics and Metabolic Efficiency Training Specialist, was gracious enough to answer some commonly asked questions for us a couple of years ago, and she’s back with updated answers! If you have more questions or are interested in working more in depth with a Registered Dietitian, her contact info and bio are included below!

What is something you hear often by nutritionists or from athletes regarding nutrition that you disagree with and why?

Many of the common diets – keto, low-carb/high-fat (LCHF), intermittent fasting (IMF) – are not appropriate for athletes, especially female athletes. Is there a way to incorporate components of those diets in a way to boost performance and optimize overall health? Most definitely! That’s what we call “periodized nutrition” which involved shifting the type and amount of your macronutrients based on your training demands. Athletes really need to understand that the research in those diets comes from obese middle-aged men with chronic disease. Studies that do use athletes have found no performance benefits of the above-mentioned diets.

GI issues are one of the main reasons runners DNF ultra marathons. How do you go about solving this common problem for ultra runners?

I spend a lot of time on this topic with my athletes, especially my female athletes. One of the reasons for this gender difference is that women absorb less fructose molecules than men; fructose is one of the primary sugars used in many sports nutrition products. So we need to look at the ingredients of the fuel the athlete plans to use. Beyond that, we look at things like the source of carbohydrates: e.g. gels are oftentimes malabsorbed because the load on the gut is so high, so too many gels can just sit in the gut a wreak havoc, drawing water into the intestines and causing diarrhea.  Compare this to blocks/chews which athletes can regulate more easily, and the load is less. When it comes to real food, we ask similar questions, and we need to also look at the fat and protein content, the type of fiber (if any), or any artificial sweeteners or sugar alcohols that can cause GI distress. Finally, especially for my ultra-endurance athletes, we need to address flavor fatigue – e.g. because most drinks, gels, gummies, chewy candy, etc., are fruity flavored, athletes can get flavor burnout which can actually lead to nausea and prevent them from getting adequate fuel. Real food can play a critical role with this.

On another note, an area that athletes oftentimes neglect regarding GI function is hydration. Consuming a drink that is too high or too low in its osmolarity (the concentration of the drink e.g. sugar, electrolytes) can end up causing diarrhea and/or dehydration.

Regardless of your race distance, event type (cycling versus running), your gender, and your digestion, it is crucial to trial nutrition strategies in training that mimics the race duration, intensity, and climate.

What is one or two big changes a runner could make with their day to day eating that could have the biggest positive impact on performance? (of course we’re all different, but think about the general runner population and one or two changes or tweaks we could all benefit from making)?

For women: no fasted training

For all athletes: even if your daily nutrition is not ideal, prioritize your nutrition around training – go in fueled for training and according to the goals of the training session, fuel & hydrate during training as necessary, and get in proper recovery nutrition within 30-40 minutes afterwards.

What are your “go-to” fueling sources during competitions? (or recommendations). How do these fueling sources vary depending on the events you’re competing in or coaching?

My own go-to fueling strategies: I’ve been a dedicated UCAN user since 2018. UCAN’s products are really unique in that they use hydrolyzed corn starch as their carbohydrate source. This Superstarch© molecule releases into the system like a drippy faucet, rather than most sports nutrition products using simple sugars which are more like a fire hose. The result? Zero GI distress, and really stable and long-lasting energy. I don’t feel those big highs and lows that are typical for a simple sugar-based fuel, and I can take in fewer grams of carbohydrates per hour, which also reduces the risk for GI upset late in a race, run, or ride. UCAN has electrolytes (UCAN Hydrate©), carbohydrate powder (Superstarch© Energy), bars which also use their patented Superstarch©, and protein powders in both whey- and plant-based options. One of my favorite things about UCAN is that they offer Cinnamon and Cocoa-flavored carbohydrate powder, which really helps with the flavor fatigue I talked about above. I use a combination of UCAN bars, UCAN Hydrate, and their Cinnamon or Cocoa Energy for my trail runs or bike rides.

I have run several ultras using solely UCAN. But beyond UCAN, I like the Skratch chews, which I save for the last 1/3 or ¼ of my race/training when I might be craving some simple sugars, and there is less likelihood I will develop GI issues. They use as their primary sugar, and they are a bit tart, rather than overbearingly sweet. They have a lemon-lime with matcha (thus caffeine) that I love.

I also always like to have salty stuff on me for events >3 hours. I will usually have Base Salt on me as a backup, just in case my stomach turns south. Otherwise I like olives, pickles, Larabars, or flour tortillas with almond butter & salt or melted cheese. For bike rides (road or MTB) I am HUGE fan of PayDay bars – since they don’t have chocolate, they won’t melt in the heat or from the body heat coming off my back, and they are the perfect blend of sweet & salty, with carbs, protein, and fat.

Sports nutrition products I recommend: low-fructose items without artificial sweeteners or sugar alcohols:

• UCAN
• Skratch chews and Super Fuel
• Nuun Sport & Endurance
• Tailwind Endurance Fuel
• Larabars or other whole-food based bars
• Spring Energy
• Base Salt, as needed

Real food I recommend: remember that real food is oftentimes just as good as packaged sports nutrition, and usually less expensive. Research studies have shown that bananas, PBJ, and chocolate milk are just as effective as sports bars and sports drinks.

• PBJ or PBH cut into quarters
• Trail mix (leave out chocolate if it’s warm outside) using any of the following: nuts, seeds, dried fruit, cereal, pretzels, chocolate
• Gummy candy or fruit snacks that don’t use high fructose corn syrup
• Candy bar such as PayDay
• Quesadillas, pierogies, salted potatoes, salted rice balls, mashed salted sweet potatoes
• Nut butter packets that include sugar, honey, or maple syrup
• Olives, dolmas/dolmates/stuffed grape leaves
• Homemade energy balls: mixing oats or cooked rice, liquid sweetener, nut butter, dried fruit (optional ingredients such as protein powder, coffee beans, spices)

We’ve seen lots of runners have low iron/anemia issues. What are some strategies for avoiding this?

There are a few components here:

• Get lab work regularly, and make sure you have a full iron panel (ferritin, transferrin saturation, TIBC, RBC, Hct, Hgb)
• Know if you are at risk for being low: female, heavy menstruation, endurance athlete, runner, vegan or vegetarian
• Consume iron-rich foods, such as fortified breakfast cereals, canned beans, tofu, baked potatoes, pumpkin seeds, unsulphured blackstrap molasses, red meat, organ meat, clams, mussels, oysters, and salmon or sardines canned in oil with foods rich in vitamin C, such as strawberries, citrus, kiwi, pineapple, mango, broccoli, bell peppers, hot peppers, and tomatoes
• Avoid calcium-rich foods when you consume high-iron foods. Calcium-rich foods include dairy (milk, cheese, yogurt, cottage cheese, ice cream) & dairy-substitutes (e.g. non-dairy milk), whey protein, almonds, edamame, calcium-set tofu, chia seeds, canned fish with bones, white beans, collard greens & kale, amaranth, calcium-fortified OJ
• Consume iron-rich foods at least 2 hours before or after exercise, rather than within 2 hours of training. This is because exercise increases the levels of hepcidin in the body; hepcidin is a hormone that reduces liver absorption by the body.

Along the lines of iron, do you recommend supplements? Any supplements that you think the general runner population should be considering? (again, I know we’re all different, but what are some generalities regarding supplements?)

This definitely depends on the individual – gender, age, ethnicity, geography, time of year, lab work/medical history, dietary habits, sport. I always advocate for “Food first, supplement second.” However, vitamin D is one I recommend to nearly all of my athletes, at least in the winter months (October-April); 400-2,000IU will do. If an athlete trains indoors or wears sunscreen during the summer months, I will recommend that they take it year-round. Depending on dietary intake and menstrual function, I oftentimes have female athletes include a Calcium-Magnesium-D supplement. Outside of that, it really does depend, and many athletes should periodize their supplements as well.

Help us make heads or tails in terms of “carbo loading”. What does it mean? Is it a myth? Is there anything in particular we should be considering in the days leading up to a big endurance event?

Carbohydrate loading definitely has a time and a place. First, carbohydrate loading should be considered ONLY if the event in question is >90 minutes. This comes down to the amount of stored carbohydrate (glycogen) in the body and how long those stores last during exercise. Second, once you have determined that carbohydrate loading is appropriate, you need to plan for the total amount of carbohydrates that should be loaded (8-12g/kg/d), the type of carbohydrates that should be loaded (low-fiber, low-residue), and the timing of carbohydrate loading (3 days prior to the event). Finally, to really benefit from a carbohydrate loading protocol, you should also be tapering your exercise in tandem with your increased intake of carbohydrate. And always be intentional about adequate hydration!

If you could give us endurance runners one piece of advice relating to food and diet, what is the mindset, mantra, advice that you would impart on us?

Put just as much consideration into your nutrition plan as you do your training plan. Your training does not look the same every single day, so neither should your nutrition. If you adopt a “fuel for the work required” mantra, you can experience both a boost in performance, but also improved daily energy and overall chronic health. If you have questions, hire a Registered Sports Dietitian who specializes in athletes like you!

For Heidi’s bio and contact info, visit: https://gritlink.net/provider/heidi-strickler