Eating for Endurance

What’s the best way to fuel for the Boston Marathon?

Should I eat a high fat diet to train my body to burn more fat and less glucose?

What percent of calories should come from carbohydrate? protein? fat?

When it comes to eating for endurance, today’s athletes are confronted with two opposing views:

  • Eat a traditional carbohydrate-based sports diet, or
  • Eat a fat-based diet that severely limits carbohydrate intake.

What should an eager marathoner, Ironman triathlete, or other endurance athlete eat to perform better? Here’s what you want to know about eating for endurance, based on the Joint Position Statement on Nutrition for Athletic Performance from the American College of Sports Medicine, the Academy of Nutrition and Dietietics, and Dietitians of Canada.

  1. Eat enough calories.

Most athletes need ~21 calories per pound (45 cal/kg) of lean body mass (LBM). That means, if you weigh 150 pounds and have 10% body fat, your LBM is 135 pounds and you require about 2,800 calories a day. That said, energy needs vary from person to person, depending on how fidgety you are, how much you sit in front of a computer, how much muscle you have, etc. Hence, your body is actually your best calorie counter—more accurate than any formula or app!

If you eat intuitively—that is, you eat when you feel hunger and stop when feel content, you are likely eating enough. If you find yourself stopping eating just because you think you should, if you are feeling hungry all the time and are losing weight, you want to eat larger portions. Under-fueling is a needless way to hurt your performance.

If you can’t tell when enough food is enough, wait 10 to 20 minutes after eating and then, mindfully ask yourself “Does my body need more fuel?” Athletes who routinely stop eating just because they have finished their packet of oatmeal (or other pre-portioned allotment) can easily be under-fueled. Even dieting athletes want to surround their workouts with fuel. Their plan should be to eat enough during the day to fuel-up and refuel from workouts, and then eat just a little bit less at the end of the day, to lose weight when they are sleeping.

  1. Eat enough carbohydrates.

According to the Position Statement on Nutrition for Athletic Performance, the optimal amount of carbohydrate on a day with one hour of training is 5 to 7 grams carb/kg. On high volume days, you need about 6 to 12 g carb/kg body weight. For a 150-pound (68 kg) athlete, this comes to about 350 to 800 grams carb a day—the equivalent of about one to two (1-lb) boxes of uncooked pasta (1,400 to 3,200 calories). That’s more than many of today’s (carb-phobic) athletes consume. You want to make grains the foundation of each meal: choose more oatmeal for breakfast; more sandwiches at lunch; and more rice at dinner to get three times more calories from carbs than from protein. Otherwise, you set the stage for needless fatigue.

  1. Eat adequate­—but not excess—protein.

Protein needs for athletes range from 1.4 g/kg (for mature athletes) to 2.0 g protein/kg (for athletes building muscle or dieting to lose fat). For a 150-pound (68 kg) athlete, protein needs come to about 95 to 135 grams protein per day, or 25 to 35 grams protein four times a day. That means 3 eggs at breakfast (with the bowl of oatmeal), a hearty sandwich at lunch, portion of lean meat/fish/chicken at dinner, and cottage cheese (with fruit) for an afternoon or bedtime snack.

For vegetarians, generous servings of beans, hummus, nuts and tofu at every meal can do the job; a light sprinkling of beans on a lunchtime salad will not. By consuming protein every 3 to 5 hours, you will optimize muscle building and deter muscle breakdown.

  1. Fill in the calorie-gap with fat.

Include in each meal and snack some health-promoting, anti-inflammatory fat: nuts, salmon, peanut butter, avocado, olive oil, etc. Fat adds flavor, offers satiety, and is a source of fuel for endurance exercise. Training your muscles to burn more fat for fuel happens when you do long, steady “fat burning” exercise. By burning more fat, you burn less of the limited carbohydrate (muscle glycogen, blood glucose) stores. You will have greater endurance and avoid or delay hitting the wall.

A (tougher) way to train your body to burn more fat is to severely limit your carbohydrate intake and push your fat intake to 70% of your calories. That could be 1,800 calories (185 g) of fat per day. This very high fat diet produces ketones and forces the body to burn ketones for fuel. Keto-athletes endure a tough, 3- to 4-week adaptation period as their bodies transition to burning fat, not glucose, for fuel. While some keto-athletes rave about how great they feel when in ketosis, the sports nutrition literature, to date, reports little or no performance benefits from a ketogenic sports diet. It might nix sugar binges, but it’s unlikely to make you a better athlete.

  1. Drink enough fluids.

A simple way to determine if you are drinking enough fluid is to monitor your urine. You should be voiding dilute, light colored urine every 2 to 4 hours. (Exception: athletes who take vitamin supplements tend to have dark colored urine.) You want to learn your sweat rate, so you can strategize how to prevent dehydration. Weigh yourself nude before and after one hour of race-pace exercise, during which you drink nothing. A one-pound drop pre- to post-exercise equates to 16 ounces of sweat loss. Losing two pounds of sweat in an hour equates to 32 ounces (1 quart). To prevent that loss, you should target drinking 8 ounces of water or sports drink every 15 minutes. Athletes who pre-plan their fluid intake tend to hydrate better than those who “wing it.”

  1. Consume enough calories during extended exercise.

If you will be exercising for longer than 60 to 90 minutes, you want to target 40 to 80 calories (10 to 20 g) of carbohydrate every 20 minutes (120 to 240 calories per hour), starting after the first hour (which gets fueled by your pre-exercise food). If you are an Ironman triathlete, long distance cyclist or ultra-athlete who exercises for more than three hours, you want to target up to 360 calories per hour. The key is to practice event-day fueling during the months that lead up to the event. By training your gut to tolerate the fuel, you’ll be able to enjoy the event without fretting about running out of energy.

The bottom line:

If you are going to train, you might as well get the most out of your workouts. Performance improves with a good fueling plan. Eat wisely and enjoy your high energy!

Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes at her office in Newton, MA (617-795-1875). Her best-selling Sports Nutrition Guidebook and food guides for marathoners, cyclists and soccer players offer additional information. They are available at For her popular online workshop, see


Thomas, T at el. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine: Nutrition and Athletic Performance. J Academy of Nutrition and Dietetics. 2016; 116 (3):501-28

Top 5 Training Mistakes and How to Avoid Them

No matter how many years we’ve been running or how many races we’ve done, there are still some mistakes we may be prone to.

1 – Avoiding the Magic Mile

Jeff Galloway has given us a great tool to determine how fast to run our long runs, race rehearsal runs, and speed workouts. It’s called the Magic Mile (MM), and when we know our MM time, we can run with a plan. When we don’t have a recent (or any) MM, we are just running by feel, which sometimes can get us into trouble.

Solution: Run a Magic Mile every 4 to 6 weeks and check the MM calculator at to see your recommended paces and run/walk ratios.

2 – Running the long ones too fast

Whether we let our friends set the pace or we “just feel good” when starting out on our long runs, it can be easy to fall into the trap of running these too fast. The long run should be at least 2 minutes per mile slower than race pace. You can’t be hurt by running the long ones too slow but running them too fast means you won’t be as recovered as necessary for the rest of your training.

Solution: Know your long run pace based on your Magic Mile prediction and don’t let anything pull you faster.

3 – Cutting the long run too short 

A marathon or half-marathon is a long way to run. Those who are best prepared for the distance will have the most fun during the race, but many runners balk at doing 14 miles in training for a half-marathon or 26 in training for a marathon. Whether they have difficulty carving out enough time for the long ones or they want to “save the real distance for race day,” they will be more likely to “hit the wall” because their bodies are not ready for the demands of the distance.

Solution: Put the long runs on your schedule months in advance and protect those days like you would an important appointment so there’s less chance you’ll be tempted to skimp on the distance.

4 – Not listening to your body when it needs to rest

Small aches and pains come with the territory, not the territory of running, but the territory of living. Not everything calls for time off from running, but when something is affecting your gait (the way you run) or is causing you to feel lethargic, you need some extra time off. Whether the condition was caused by running or some other stress like work, continuing to push yourself when your body needs rest can lead to injury.

Solution: Turn a run day into a walk day. Get out and enjoy the fresh air without any worry about how fast you are going. Even if you have to miss a long run, walking that same distance will give you the endurance you need. If you don’t feel better in a couple of days, see your family doctor.

5 – Ignoring nutrition

On race day you will have your socks picked out, your shoes well tested, and the rest of your outfit just right. You will have done the long runs and honed your pace if you have a time goal, but what will you have done for nutrition? If you haven’t practiced what you will have for dinner the night before, breakfast race morning, and during the race, you are ignoring an important factor that will impact your race day experience.

Solution: Use your long run weekends to practice race weekend nutrition, right down to the flavor of sports drink you intend to use. If something isn’t going to work for you, better to find out a month before race day than when it’s all out there on public display.

By Chris Twiggs, Galloway Training Director

Key Workouts

Welcome to Week #4.  Yeah, we “get to” workout!  It certainly is a privilege.

If at all possible, please do not miss the Saturday long runs.  Long runs are run at least 2 minutes per mile slower than your goal pace to reduce wear and tear on your body.  Reducing the impact on the body means you can recover quicker from training runs and can continue progressing with your training.  There are many physiological adaptations the body makes in order to meet the physical demands of distance running, and this is why slowing down is recommended.

If you’re new to distance training, many of your training runs are going to take you into new mileage territory.  When running a new distance, it should be considered a “long” run, regardless of the actual mileage.

Below is an explanation of the types of training we will be doing this session.  The goal is to improve the pace of your run through practice.

Cadence Drills (Wednesdays/Thursdays)

It’s an easy drill that improves the efficiency of running, making running easier.  This drill excels in how it helps to pull all of the elements of good running form together at the same time.  Studies have clearly shown that as runners become faster, their stride length decreases.  Therefore, the way to get faster is to increase the turnover of your feet and legs.  Even those who lack a fast bone in their bodies will benefit from cadence drills because they teach the body to find a more efficient motion.  Over the weeks and months, if you do this drill once every week, you’ll find that your normal cadence slowly increases naturally.

Acceleration-Glider Drills (Wednesdays/Thursdays)

This drill is a form of speed play, or fartlek.  By doing it regularly, you develop a range of speeds with the muscle conditioning to move smoothly from one to the next.  The greatest benefit comes as you learn how to “glide” or coast off your momentum.  The main object of the drill is to keep moving at a fairly fast pace without using much energy.

Hill Repeats (Mondays/Tuesdays)

Running uphill makes you stronger.  It’s actually the most efficient form of strength training for runners since it uses all the muscles you activate when running on flat surfaces but builds greater strength due to the increased resistance.  Your legs are not used to being pushed to run uphill and downhill regularly.  Therefore, they may be a little sore at first as you get used to hill training.  They will adjust, though, and start to gain tone and definition.  Running uphill and downhill will also help get your entire body into better shape.  Unlike regular running, your heart rate will go up when you run hills because your body will need to work harder to do it.  This will get oxygen flowing through your body more quickly and help you build up more stamina.

Long Run (Saturday)

The long run is truly the bread and butter of an endurance training program.  It teaches your body how to spend time on its feet, how to utilize fat as a primary fuel source, and is a dress rehearsal for your goal race.

Rules of the Road

Welcome to Week #2!

Last Saturday, many of you did your Magic Mile (one-mile time trial) and received your individual training recommendations.  Accordingly, we will have pace groups on Saturdays.  During the week, you will practice your predicted race pace and intervals after the hill repeats and drills.  Don’t worry.  It all magically comes together on race day to make you stronger and faster.  Trust your training!

Long runs are run 2 minutes per mile SLOWER than your predicted race pace to reduce wear and tear on your body.  We may further back down the pace if it’s hot or if people are huffing and puffing.  Reducing the impact on the body means you can recover quicker from training runs and can continue progressing with your training.  There are many physiological adaptations the body makes in order to meet the physical demands of distance running, and this is why slowing down is recommended.  These physical adaptations do not simply happen overnight.  The adaptation process is stimulated when the demands of training are greater than what the body is prepared to meet.  The physical overload triggers the adaptation process.  Each time we go above and beyond, which is known as progressive overload, we stimulate this adaptation process.  When we overload the body in gradual, incremental increases, it responds positively by becoming stronger.  If we overload the body too rapidly or too heavily too soon, it doesn’t have time to adapt and we risk poor performances, injury, illness, and/or mental burnout.

It takes discipline to run fast, to slow down, and to rest.  All three are important! 



Group Leaders will always do their best to look out for the safety of the group, but contrary to popular belief, they are not infallible.  SAFETY IS ULTIMATELY YOUR INDIVIDUAL RESPONSIBILITY.  Please don’t take up the whole road or trail – run no more than two abreast.  Please look both ways to ensure the road or trail is clear before crossing.  On the trail, if you alter your direction, look over your shoulder before crossing the trail to avoid a potential collision with an oncoming cyclist or passing runner.  On the road, be sure the driver of a car acknowledges your right-of-way before crossing in front of a vehicle.  Obey traffic signals.


Group Leaders will always carry a cell phone in case of emergency.  Additionally, we maintain a list of all members and their emergency contact’s name and telephone number.  Hopefully we never need to use this list.


If it’s just raining, we’ll run.  It might be raining on your race day, so training in the rain may come in handy.  If there is LIGHTNING in the area, we don’t run.  I will text everyone if training is cancelled for any reason.


Water bottles are REQUIRED on all runs over 10 miles.  We encourage everyone to find a water bottle and carry it with you, even on shorter runs.  Group Leaders may refuse to allow you to run with the group if you don’t carry water.  Dehydration is one of a marathoner’s worst enemies and can occur even before 10 miles, especially on particularly hot and humid days.  Like going out too fast, when one becomes seriously dehydrated, you cannot recover from it during a run.  Only rest and hydration will help.


Any time we’re running on a road with no sidewalks, we should run on the left side of the road, facing traffic.  By facing oncoming traffic, you may be able to react quicker than if it’s behind you.  When sidewalks are present, we may choose to run on the right side of the road based upon the quality of the sidewalks and depending on our next turn, but otherwise, LEFT SIDE PLEASE.


Group Leaders and everyone should call out “CAR UP” or “CAR BACK” (or BIKE, RUNNER, etc.).  If you see some other hazard, such as a “PUDDLE” or “ROCK” or “BRANCH” or “SPEED BUMP” in the path (you get the idea), please call it out.  We don’t need any injuries from someone tripping over something, especially when we’re bunched up a bit, as more than one runner could fall.


It’s important to let your Group Leader know if you start to experience any nagging aches or pains resulting from our runs.  By catching issues EARLY, we can usually avoid more severe injuries later.  Sometimes, it may be necessary to reduce your mileage or consider moving you to a slower running group to avoid injury – DO NOT TAKE IT PERSONALLY.  One of the major goals of this program is to RUN INJURY FREE.  The program incorporates the walk breaks and sets mileage in order to minimize the chance of injury during the training process.  Finally, as Jeff Galloway states in his “Galloway Training Programs” book, it is okay to be tired, particularly after a long run.  But, if you’re so exhausted that all you do for the rest of the day is lie on the couch, or are very sore, you probably have run too quickly.  So, PLEASE LET US KNOW AT THE FIRST SIGN OF INJURY – this is important for you and important for the group.


It’s never a good idea to leave someone behind or alone, even a veteran runner.  The Group Leader (or another responsible person) should drop back with the person having problems, and let the group run on, or the whole group can slow down together depending on the circumstances.  WE ARE ALL IN THIS TOGETHER, and supporting each other is part of the process.


As you will discover, there are a lot of aspects to that statement.  Successfully running long distance is not about speed, it is about building ENDURANCE.  You can have all the speed in the world, but if you have not built up the endurance to sustain it, it will not do you any good.