Athletes tend to do a good job of training their muscles, heart and lungs. But some of them (particularly endurance athletes and those in running sports) commonly fail to train their gut. As one marathoner reported, “I was so afraid of getting diarrhea during long training runs that I did not eat or drink anything beforehand. I really struggled after 14 miles…” A high school soccer player admitted, “I’m so afraid I’ll throw up if I run with food in my stomach.” He ate only a light lunch at 11:00 and then practiced on fumes at 3:30. No wonder he had a disappointing season.

An estimated 30-50% of endurance athletes (including up to 90% of distance runners) have experienced gastro-intestinal (GI) issues during and after hard exercise. They fear bloat, gas, nausea, stomach cramps/pain, side stitch, diarrhea, vomiting, and urge to defecate. These issues arise during long bouts of exercise because blood flow to the gut is reduced for an extended period of time. When combined with dehydration, elevated body temperature and high levels of stress hormones, normal intestinal function can abruptly end.

If you are an athlete with a finicky GI tract, restricting your diet before and during exercise will not solve the problem. You want to learn how to train your gut to accommodate performance enhancing carbs and water. That way, you can train better—hence compete better—without stressing about undesired pit stops.

Thankfully, the gut is trainable. Competitive eaters have proven this point. Google Nathans’ Hot Dog Eating Competition and watch the video of a champ who stuffed 72 hotdogs into his stomach in 10 minutes. Clearly, he had to train his gut to be able to complete that task.

Competitive eating is unlikely your goal, but you may want to be competitive in your sport. That means you need to fuel wisely in order to perform optimally. While some “keto-athletes” choose to train their bodies to rely on fat for fuel (fat is less likely to cause GI distress), training the gut is a far easier alternative for most of us.

The following tips can help you exercise with digestive peace.

• Drink enough fluids. Dehydration triggers intestinal problems. Your goal is to drink enough to prevent 2% dehydration (sweat loss of 2 pounds per 100 pounds of body weight from pre- to post-exercise). If you are a “big guy” who sweats heavily, this can be a lot of fluid. For example, a 200-pound football player could easily lose 4 pounds (a half-gallon) of sweat in an hour of exercise. He needs to train his gut to handle fluid replacement during training. He could need as much as 12 to 16 ounces every 15 minutes during a two-hour practice.

• Feeling “full” and “bloated” during exercise indicates fluids (and foods) have not emptied from the stomach. This commonly happens during really hard exercise, when reduced blood flow to the stomach delays stomach emptying. Hot weather and prolonged exercise in the heat can also reduce stomach emptying.

• You want to dilute highly concentrated carbs (i.e., gels), so be sure to drink enough water during exercise (i.e. 16 oz. water per 100 calories gel).This will help speed up gastric emptying.

• If you plan to eat a peanut butter on a bagel before you compete, you want to routinely eat that before important training sessions. This helps train your gut to accommodate fat (sustained energy) as well as carbs (quick energy).

• Once carbohydrate (such as sport drink, gel, banana, or gummi bears) empties from the stomach, it enters the small intestine and is broken down into one of three simple sugars (glucose, fructose, galactose). These sugars need “taxi cabs” to get transported out of the intestine and into the blood stream.

• Too many gels or chomps without enough transporters can lead to diarrhea. By training with your race-day carbs, you can increase the number of transporters.

• If you typically eat a low-carb Paleo or keto-type diet and then on the day of, let’s say, a marathon, you decide to fuel with carb-rich gels and sports drinks, your body won’t have the capacity to optimally transport the sugar (carbs) out of your intestines and to your muscles. You could easily end up with diarrhea.

• When planning what to eat during extended exercise, choose from a variety of carbs with a variety of sugars (i.e., sport drink, gum drops, and maple sugar candy). This helps prevent the glucose transporters from getting saturated. Too much of one kind of sport food can easily create GI problems.

• “Real foods” such as banana, raisins and cereal, have been shown to be as effective as commercial sport foods. Your body processes “real food” every day and has developed a good supply of transporters to deal with the carbohydrate you commonly eat. By experimenting and learning what works best for your body, you can fuel without anxiety about undesired pit stops.

• For exercise that lasts for up to two hours, research suggests about 60 grams (240 calories) of carb per hour can empty from the small intestine and get into the blood stream. Hence, that’s a good target. For longer, slower, events, the body can use 90 g (360 calories) carb per hour from multiple sources,as tolerated. Again, train your gut!

The bottom line  

• Train with relatively large volumes of fluid to get your stomach used to that volume.
• Routinely eat carbohydrate-based foods before training sessions to increase your body’s ability to absorb and use the carbs.
• During training, practice your race-day fueling. Mimic what you might eat before the actual competitive event, and tweak it until you find the right balance.
• If you are concerned about diarrhea, in addition to preventing dehydration, limit your fiber intake for a few days pre-event (fewer whole grains, fruits and veggies).
• Reducing your intake of onions, garlic, broccoli, apples, and sorbitol might help reduce GI issues during exercise.
• Meet with a sports dietitian to help you create a fueling plan that promotes intestinal peace and better performance.

Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875). She helps both fitness exercisers and competitive athletes create winning food plans. Her best-selling Sports Nutrition Guidebook, and food guides for marathoners, cyclists and soccer are available at nancyclarkrd.com. For online workshops:  www.NutritionSportsExerciseCEUs.com.

Nutrition misinformation and food confusion surrounds today’s health-conscious athletes. To arm myself with knowledge to better educate my clients, I (along with 10,000 other registered dietitians) attended the Academy of Nutrition & Dietetics annual convention to learn the latest food and nutrition updates. Here is some information that might help you on your health journey.

Stress fractures are a common sports injury. Among 42 Division-1 cross-country runners, 35% of the male and 41% of the female runners reported having had a stress fracture. Inadequate nutrition could have contributed to the problem. Their diets tended to be low in calories, calcium and/or vitamin D. If you are going to push your body to the limits, at least fuel it optimally!

If intestinal distress sidetracks you during exercise, try reducing your intake of apples, onion, garlic and broccoli —particularly for 2 to 3 days before a competitive event.These are just a few commonly eaten foods that are high in fermentable (gas-producing) carbohydrates; they might contribute to undesired pit stops. You could also meet with a sports dietitian to help you systematically discover triggering foods. The referral network at www.SCANdpg.org can help you find your local sports food expert.

Exercise increases harmful free radicals within muscles that can lead to oxidative damage and inflammation. Should athletes supplement with anti-oxidants to counter this? No. The better bet is to let the body adapt to these higher levels (and eat abundant anti-oxidant rich fruits and vegetables). Adaptation creates a change for the better in an athlete’s physiology.

Alcohol contributes to hypoglycemia (low blood glucose) by suppressing the release of glucose from the liver into the blood stream. If an athlete hasn’t eaten much food (as can easily happen after an event), alcohol in an empty stomach can easily lead to hypoglycemia (a lack of glucose for the brain) and a drunken stupor. The same happens when a person with diabetes has low blood glucose; he or she can get mistaken for being drunk (when the brain just needs food).

In contrast to recreational marijuana, which is used with the intent to impair normal functioning, medical marijuana (MM) is used to relieve pain, reduce nausea and vomiting, and to overcome loss of appetite (as with cancer). If you have parents or friends who are new to using MM, caution them about using edibles. When MM is eaten, its pain relieving benefits are delayed for 30 to 120 minutes, as opposed to smoked MM, which offers immediate benefits. The problem with the delayed response with edibles is that a patient can easily overdose while waiting to feel an effect…

Meal timing affects circadian rhythms —as well as weight management. A study (Garaulet, 2013)with 420 subjects who ate an early lunch or a later lunch reports the early lunch eaters lost more weight, despite consuming the same number of calories and getting the same amount of sleep. Your best bet is to eat more food earlier in the day. As you have undoubtedly heard before: Eat breakfast like a king, lunch like a prince, dinner like a pauper.

We compromise our well-being every time we have a mismatch between the environment and our internal biological clock. (Think jet lag, shift work, sleep apnea, and watching late-night TV.) Every cell has a biological clock; all these cellular clocks need to be synchronized. If not, bodies become unhealthy. For example, shift workers experience more high blood pressure, heart disease and diabetes than people who work 9:00 to 5:00. For athletes, jet lag means poorer performance.

Sleep is restorative and helps synchronize cell’s biorhythms. If you have trouble sleeping well:

• avoid caffeine at least 4 hours before bedtime and limit it to 2 mugs (400 mg. caffeine) a day.
• turn off your computer screen/TV an hour before bed.

Consumers are self-defining “healthy food.” It needs to be organic, natural, non-GMO, free of dyes/additives/ colors, and have a “clean” label with no strange words. Will this trendy definition lead to unintended health consequences as food producers try to meet consumers’ demands? Likely yes.

If you make your food decisions based on trends rather than science, you might want to take a step back and look at the whole picture. For example, enriched foods offer added nutrients that can make a label look “dirty” but the extra ingredients are good for your health. Added iron reduces your risk of becoming anemic; folic acid reduces the risk of birth defects; iodine reduces the risk of goiter. Preservatives that have been generally regarded as safe help bread stay fresh for longer, reduce the growth of mold on cheese, and reduce the amount of food you waste. These ingredients can be beneficial for you and for the environment.

Sugar-sweetened beverages are the biggest source of dietary sugar in the US diet. Hence, research on sugar and health has focused on soft drinks. The question remains unanswered: Is sugar added to nourishing foods a health hazard? That is, is sugar added to spaghetti sauce (to make it less acidic) bad for you? What about the sugar added to bread (to help make the dough rise) — Is that a cause for concern?

Doubtful. Yet, too many consumers freak out when a product lists sugar on the food label. Please note: sugar is just one of many nutrients listed on the label. Please look at the whole nutrient package. For example, chocolate milk has sugar (that refuels muscles) but it also offers protein (to repair muscles), sodium (to replace sweat loss), calcium & vitamin D to enhance bone health. Dietary guidelines say 10% of total calories can come from added sugar. That’s 200 to 300 calories a day for athletes. Do you really need to freak out about a little sugar that makes that spaghetti sauce taste better? I think you can find bigger things to worry about.

Reprinted with permission from Nancy Clark.

Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875), where she counsels both fitness exercisers and competitive athletes, teaching them how to eat to win. Her popular Sports Nutrition Guidebook, and food guides for marathoners, cyclists and soccer are available at nancyclarkrd.com. For online workshops, see NutritionSportsExerciseCEUs.com.

Food is fuel and food is medicine. Food brings people together and is supposed to be one of life’s pleasures. Shared meals are a vehicle for building relationships, enjoying conversations, and nourishing the soul.

Unfortunately in today’s society, too many athletes and fitness exercisers alike report they have no time to enjoy meals. Sports parents struggle to gather their student athletes for a family dinner; practices and games inevitably interrupt the dinner hour. And even when seated at the same table, some family members may be eating just salad while the rest of the family enjoys steak. So much for eating out of the same pot.

Today’s food conversations commonly refer to good food, bad food, clean food, fattening food. We all know athletes who don’t do sugar, gluten, white flour, or red meat, to say nothing of cake on birthdays, ice cream cones in summer, or apple pie on Thanksgiving.  We live with abundant food, but we have created a fearful eating environment with our words. This article invites you to pay attention to how you think and talk about food. Perhaps it is time to watch your mouth, so you can start to change the current culture that makes food a source of fear for many athletes.

Good food vs. Bad Food

“I eat only healthy foods —lots of fresh fruits and vegetables—and I stay away from stuff in wrappers with ingredients I can’t pronounce.“ While this may seem like a noble stance towards being a responsible caretaker for your body, it raises a few red flags for me.

• One, a diet of only healthy foods can be a very unhealthy diet. For example, apples are a healthy food, but a diet of all apples is a very unhealthy diet.
• Two, a diet with only unprocessed food eliminates refined or lightly processed grains that are enriched with vitamins and iron, nutrients of importance for athletes. For instance, “all natural” breakfast cereals like Puffins and Kashi offer only 4% to 10% of the Daily Value for iron, as compared to iron-enriched cereals like Wheaties, GrapeNuts, and Bran Flakes and that offer 45% to 100% of the recommended intake. If you eat very little red meat (a rich source of dietary iron), do not cook in a cast iron skillet (a meat-free source of iron), and eat only “all natural” grain foods, you could easily have an iron-deficient diet. This shows up in anemia and needless fatigue. A survey of female runners (ages 18-22) reports 50% had anemia, often undiagnosed.

Yes, many hard-to-pronounce and unfamiliar words like niacinamide, ferrous sulfate, and ascorbic acid are listed among the ingredients of many grain foods. These are the scientific names for the same vitamins in pills. There’s a reason why they were added to foods in the first place. Adding folic acid to grains has reduced the risk of having a baby with a birth defect. B-12 is important for vegans. Will the trend to avoid enriched and fortified foods come back to bite us? How about choosing the best of both?

Bad food vs. Fun Food

When athletes feel compelled to confess their nutritional sins to me (“I eat too many bad foods—chips, French fries, nachos… “), I quickly remind them there is no such thing as a bad food (or a good food, for that matter). Is birthday cake really a bad food? Is a hot dog at a baseball game going to ruin your health forever? Should you not make cookies with your children on a snowy day?

Those so-called bad foods are actually fun foods that taste yummy and can fit into an overall balanced diet. Rather than critiquing a single food, please judge your diet by the whole week, month, and year. Halloween candy is a fun treat in the midst of a steady intake of fruits, vegetables, lean meats and wholesome grains. So is pumpkin pie with ice cream.

Depriving yourself of fun foods creates good and bad foods, as well as a really bad relationship with food. Eating a fun food is not cheating. The problem arises when you restrict fun foods, only to succumb to devouring not just one cookie but all 24 of them. Binge-eating burdens you with not only excess body fat, but also (self-imposed) guilt for having broken your food rules, and disgust with yourself for having pigged out.

Eating the whole thing means you like that food and should actually eat it more often, rather than try to stay away from it. Contrary to what you may believe, you are not addicted to cookies. You are simply doing “last chance” eating. Last chance to have cookies (or so you tell yourself) because they are a bad food and I shouldn’t eat them at all.

There’s a more peaceful way to live. Try balancing a cookie or two into your daily menu. After all, you need not have a perfect diet to have an excellent diet. A reasonable goal is 85-90% quality foods; 10-15% “whatever.”

Healthy diet vs. A single ingredient

Salt, sugar, and saturated fat seem to be today’s food demons. Rather than look at each ingredient, I cannot encourage you enough to look at the entire food (and your entire diet). Take sugar, for example. Are the 3 grams of sugar in Skippy peanut butter really a source of evil? What about the 10 grams of refined sugar in chocolate milk? That (“evil”) sugar quickly refuels muscles after a hard workout. That’s why chocolate milk is an effective recovery food. After a hard workout, when you are tired and thirsty, but not yet hungry, the sugar in chocolate milk offers a quick energy boost that normalizes your low blood glucose and replenishes depleted muscle glycogen. While some athletes focus on chocolate milk’s 10 grams (40 calories) of added sugar, I invite you to welcome its high quality protein (needed to repair muscles) and abundant vitamins and minerals that invest in your good health. The fit bodies of athletes can metabolize sugar much better than the unfit bodies of couch potatoes.

The bottom line

You want to enjoy an excellent diet, and not strive for a “perfect” (but very strict) diet. You can win good health and perform well with a balanced diet, filled with a variety of foods, and enjoyed in moderation.

Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875), where she helps both fitness exercisers and competitive athletes create winning food plans. Her best-selling Sports Nutrition Guidebook, and food guides for marathoners, cyclists and soccer are available at nancyclarkrd.com. For online workshops, see www.NutritionSportsExerciseCEUs.com.

In this era of highly competitive sports, more and more runners, cyclists, soccer players and other serious athletes are eagerly seeking information on how to fuel optimally. Performance nutrition is also of interest to Marines, special operations troops such as the Navy Sea, Air and Land (SEAL) teams, and others in the military who need to perform at a very high level to both survive and to carry out their missions. Hence, effective fueling practices are a topic of great interest and research for the US Armed Forces.

At this year’s annual meeting of the American College of Sports Medicine (the nation’s largest group of sports medicine professionals, exercise scientists, and sports nutrition researchers; www.acsm.org), civilian as well as military exercise scientists presented the results of their recent nutrition research, some of which I have highlighted below.

This information might be of interest to you, whether you are a competitive athlete or soldier who trains for hours in the summer heat, winter cold, at high altitude, or for in preparation for a strenuous event—be it a military mission, Ironman triathlon, or an adventure race. Regardless of your reason for exercising, fueling your body wisely and well can greatly impact your ability to perform optimally today as well as invest in your future health and well-being.

Highlights of research on nutrition for military performance:

• To become a Navy SEAL, you have to go through SEAL Qualification Training. A survey of 264 of these serious “military athletes” indicates their diets rated only 56 out of 100 on the Healthy Eating Index. This is slightly lower than the score of 59 for the general US population. To the disadvantage of these trainees, their dietary patterns were low in health-protective fruits, vegetables, whole grains and fish, but high in health-eroding refined foods with added sugar, fat and alcohol. This type of eating pattern promotes inflammation. By improving their food choices (more colorful fruits, vegetables, whole grains, healthy fats), they could reduce systemic inflammation, which could enhance recovery from training, boost immune response, and help them maintain better health. As you know, an injured or sick soldier or athlete is not an asset to any team.

• Marines in training for acceptance to Special Operation Forces exercise extremely hard during their training program. One might think they would suffer from long-term undesired weight loss. Not the case. After each period of intentional severe food deprivation, the trainees manage to restore the significant amount of weight they lost. For example, in the toughest part of the 261-day training program (days 115-123), the men burned about 6,400 calories a day. They had access to only 2,400 calories of food. That’s about 4,000 calories a day less than they needed! They lost, on average, 11 pounds (4.9 kg). The Marines intuitively returned to their baseline weights after that training period, when they had access to adequate fuel. As an athlete who has dropped weight, only to regain it, you may have seen first-hand how the body works hard to defend a genetic weight. Weight is more than a matter of willpower.

• Speedy recovery from strenuous exercise is of key interest to military personnel. Beta-hydroxy-beta-methylbutyrate (more commonly called HMB; a natural by-product of protein/leucine metabolism) has been shown to enhance muscle recovery from high intensity exercise. Would HMB with supplemental probiotics (gut microbes that enhance protein absorption) be a way to enhance soldiers’ muscle recovery? To find the answer, soldiers took HMB + probiotics during 2 weeks of intense military training (carrying ~77 pounds (35 kg) of equipment while marching 16-19 miles (25-30 km) per night in tough terrain). Results of this study suggest that HMB supplementation reduced the inflammatory response to intense training. Combining HMB with the probiotic Bacillus coagulans was even more beneficial than HMB alone in maintaining muscle integrity during the intense military training.

The question now arises: Can athletes who eat a high quality diet with leucine-rich food (meat, fish, chicken, cheese, whey) + probiotic-supporting fiber-rich food (vegetables, fruit whole grains) reap the same benefits? Sounds like a winning combination to me!

• Staying healthy is important for soldiers and athletes alike; neither have time for illness due to upper respiratory tract infections (URTIs) such as colds. Would taking a high does of Vitamin D, which has been shown to improve immune function, offer protection? To answer that question, Marines in basic training received daily for 12 weeks either 1,000 IUs of Vitamin D-2 (the RDA is 600 IU) or a placebo. The majority (72%) of recruits reported getting a URTI during the 12 weeks. The high dose of Vitamin D did not offer a protective effect in this highly stressful environment. Perhaps you could instead focus on having clean hands and getting adequate sleep.

• Now that women can perform combat duty, a question arises: How well can the women perform physically compared to the men? To find the answer, 302 marines underwent comprehensive testing including strength, flexibility, balance, power, agility, and physical fitness tests (pull ups, push ups, sit ups, bench press, 2-mile run, etc). They then were stratified into three groups according to the test results, regardless of sex or body fat: best (all men), middle (mostly men), worst (mostly female).

When compared by sex, the men, understandably, tended to have less body fat—except when compared to the best performing women. The amount of the male or female marines’ muscle-mass determined athletic performance more so than their body fatness. The best-performing men and women in groups one and two had significantly more muscle than the men and women in group three. The researchers concluded that muscle mass may have a stronger association with performance during strength, aerobic, and anaerobic tests than does percent body fat. This is a good example of how the leanest athlete is not inherently the best athlete. For some athletes, building more muscle might be more important than losing body fat.

Sports nutritionist Nancy Clark MS RD CSSD has a private practice in the Boston-area (Newton; 617-795-1875), where she counsels both fitness exercisers and competitive athletes, teaching them how to eat to win. Her popular Sports Nutrition Guidebook, and food guides for marathoners, cyclists and soccer are available at nancyclarkrd.com, as well as information about her online workshop and teaching materials.

In my humble opinion, peanut butter (PB) is one of the best sports foods around. Not only is it yummy, it is also health-promoting and performance enhancing. A review of the research on peanuts validates why I routinely choose to enjoy two (!) PB sandwiches a day: one for lunch and the other to curb late-afternoon hunger.