Marathon Fueling Q & A

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Hi, I'm Tina!

I’m the owner of Carrots ‘N’ Cake as well as a Certified Nutrition Coach and Functional Diagnostic Nutrition Practitioner (FDN-P). I use macros and functional nutrition to help women find balance within their diets while achieving their body composition goals.

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Remember when I asked you guys if you had questions for Lauren Antonucci from Team for Kids about marathon training and fueling? Well, I gathered up your questions, sent them to her, and she replied to them. Check out Lauren’s responses below. She provides a ton of great information! Thanks, Lauren!

I think that I’m refueling wrong as I’m always STARVING after my long runs! What and when should I eat to keep this from happening?

Take a step back to focus on your DURING run fueling, as that is most likely where you’re short changing yourself. Are you getting in 30-60 grams of carbohydrates (150-200 calories) per hour during your long runs? To find out, add up all the calories you ACTUALLY consumed during your last long run (from sports drinks, gels, blocks, crackers etc) and divide that number by the number of hours you ran for. If you are not consuming at least 150-200calories/hr add additional products/calories until you are comfortably in that range. Also ensure you get both carbohydrates and a little protein within 30 minutes after your run to help prevent that post run starvation feeling as well as to facilitate muscle recovery. (*see my answer to the next reader question for how to best get those calories in during your runs)

I’ve read the body needs 30-60g of carbohydrate per hour for any runs lasting longer than an hour. What time is the best to take in this fuel?

Good reading! I am glad to see you are focusing on optimal fueling as it will literally take you far! To best absorb and utilize the calories you take in while running and also best stabilize your energy level you should be taking in some calories every 15-20 minutes. I recommend thinking about breaking your calories into 50 calorie increments (8oz of Gatorade endurance, 1/2 gel or 2 shot blocks) and taking one 50 calorie unit every 15-20 minutes for even fueling.

How important is it to refuel with something like Gu or other energy gels mid-run?

Imperative! The goals of fueling while running include maintaining your energy level, pace and performance and  providing your brain with glucose while you run. I guarantee that once you find the right combination of products that work well for you logistically and in your GI track (leaving your stomach and intestines happy and preventing undesirably emergency port o let stops), you will feel better for less effort when you fuel properly. Additionally, studies show that “investing” in needed calorie intake during training can easily “save” you more than double that number of calories later in the day because you will not be as starving after your run (see reader Q&A one here).

What distance requires something extra versus just normal eating?

The answer to this question really depends on your normal eating and normal exercise routine as well as your desire to lose vs. maintain vs. gain weight. That said, I see many newly transformed runners training for a marathon who come to see me for nutritional analysis and meal planning because they had been GAINING weight while marathon training. How could this be? Well, exactly as your question implies, it is easy to eat more than you expend even while training for a marathon. The bottom line here is that you only need to fuel your increased training on days when your training has actually increased. Meaning that if you always exercised for 45 minutes 4x/week and are now training for a marathon by running 45 min 3x/week plus one longer run, your needs have only increased by ~100 calories x the number of extra miles you run on that fourth training day. If you are looking to achieve a (gradual, healthy) weight loss while training, you should of course cut back slightly in total daily calorie intake to achieve your weight loss goal.

What’s the best way to train for a marathon, but not lose lean muscle mass in the process?

Consuming adequate total protein and total calories will help ensure you are able to supply your muscles with what they require in order to repair, strengthen and rebuild after each long run. In doing so you will minimize/avoid loss of lean muscle mass while your training increases. I see countless runners/endurance athletes in my office each year who are under eating (either in an attempt to lose weight while training or inadvertently do to an inability to “keep up” with increased calorie demands during increased training). They usually complain of frequent injuries, recurrent illness and/or generally poor recovery following long runs. By measuring their Resting Energy Expenditure (REE), analyzing their food log and adjusting their daily meal plan they are able to get them back on track in no time. If you are having trouble keeping up with your daily calorie needs or think you are  losing muscle mass while training, a visit with a Board Certified Sports Dietitian (CSSD), for REE test and evaluation should help you meet your needs and allow you to train & stay strong.

When training for a marathon, what ratio of carbs/protein/fat should you aim for in your diet?

Good question. Athletes often ask me questions about the ideal macronutrient ratios, likely because there are numerous books and articles written on the subject. Ratios, however, are NOT the best way to determine your nutritional needs because three are MANY factors which alter one’s individual needs. I always calculate each individual’s absolute protein needs first. I do this as grams of protein/KG of body weight. Protein needs can vary widely from 1.2 grams/kg to 1.6-1.8 grams protein/kg for a vegetarian female marathoner in heavy training desiring moderate weight loss. Thereafter, I calculate each athletes total carbohydrate needs. Total carb needs can range widely, from 3-10grams of total carb/kg body weight/day, based on training volume and weight maintenance/loss/gain goals as applicable), then last but not least, I calculate total fat needs. Based on my calculations of all three macronutrients (protein, carbs & fat), and total daily calorie needs, the ratios can vary widely. For example protein may need to make up 12-20% of total calories, carbs may range from 50-65% of total calories, and fat can comprise 20-30% of total calories depending on the individual factors. So as you can see, determining your  macronutrient needs involves looking at many factors, & requires much more than a simple ratio. 

Do women need more protein in their diets when training for a marathon? If so, how much?

If your question is, do women need more total protein per day during high volume training blocks vs times of lower training, then yes! Depending on other factors as I discussed in the last question (vegetarianism, weight loss goals) & other factors such as total training volume, cross training, strength training needs, the average range should generally be between 1.2-1.8grams of protein/kg body weight per day.

I’m wondering if I should just eat anytime I’m hungry during marathon training or if I should keep to a normal eating schedule? I want to eat properly and keep my body energized, but I also don’t want to overeat!

Another great question! Ideally, I instruct clients to eat when hungry and stop when comfortably full. That mantra still applies during marathon training as long as three factors are true. 1) You are choosing MOSTLY healthy foods. Aim for 90% healthy, nutritious choices, 10% “treats”. 2) You are adequately hydrated. Dehydrated often leaves us feeling hungry when we are in fact thirsty. 3) You are getting adequate amounts of each macronutrient (carbs, proteins, fat). If all of the above are true then by all means increase your food intake to meet your increased hunger due to increased training. If, however, too many of your food choices are empty calories OR you think you might be either dehydrated or short changing yourself of one of the 3 macronutrients above, then straighten that out first and then reassess your hunger once you are adequately fueling your body.

What is the best fuel for right before a run and the best meal to eat as a post-run recovery meal?

Your pre run meal should be mostly easily digested carbohydrates that you are familiar with and know you tolerate well. It is ok to include a bit of protein and/or fat in this meal, but just a bit. Ex, peanut butter on toast or 1 egg and oatmeal. For post run recovery aim to replace all fluids lost to sweet during your run as well as more easily digested carbs and a little protein. Ex include a sandwich & fruit smoothie or pasta with marinara sauce, salt and 3oz of chicken.

Are there specific foods that runners should focus on eating?

An overall well balanced plan full of complex carbs, fruits, veggies, low fat dairy and lean protein with “good fats” will optimally fuel you. Be sure to include a wide variety of foods and not to avoid/miss any particular food group. Focus on high antioxidant and anti-inflammatory foods to optimize health and recovery from training. And don’t forget to stay well hydrated.

Are some people just built for running and others not?

Nutritionally speaking this question really applies to physiology. Meaning, it is much easier for runners with a self proclaimed “stomach of steel” to fuel up before during and after long runs. That said, I work with numerous marathoners/triathletes with “sensitive stomachs”, IBS, type 1 & type 2 Diabetes etc that do very well once they understand their particular fueling needs. Bottom line, anyone can run if they figure out what works for them!

I hope this helps you all fuel better and  feel better in all of your running/sports endeavors!

Lauren Antonucci, MS, RD, CSSD, CDE, CDN


Lauren Antonucci, MS, RD, CSSD, CDE, CDN is a Registered Dietitian, Board Certified Specialist in Sports Nutrition, Certified Diabetes Educator, 3x Ironman Triathlete, 13x (and 3:09 PR) marathoner, mother of 3, and Owner/Director of Nutrition Energy; a nutrition consulting practice in NYC. You can find additional information about Lauren and her practice, Nutrition Energy, on the web: Follow her on twitter: @NutritionEnergy and look for NutritionEnergy on FaceBook.

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