Ketosis is a metabolic state similar to starvation in which energy is provided primarily by high fat intake, adequate protein intake (1 gram/Kg lean body mass) and low carbohydrate intake. The idea is to switch your body to using fat as fuel, instead of the usual carbohydrates. The keto diet has traditionally been used for weight loss, but now some athletes have taken up the diet as well. 

How does it work? 

Carbohydrates are initially restricted to 10 grams per day (15 to 20 grams per day in adolescents and adults), with patients counseled to increase their use of high fat foods (at the expense of protein). Traditionally, the diet consists of four parts fat to one part protein and carbohydrate (i.e., a 4:1 lipid to non-lipid ratio). Total calories are restricted to 80 to 90 percent of recommended values for age (Kossoff et al., 2009).  By eating a diet like this, the body becomes very efficient at utilizing fat for energy and produces higher levels of ketones (acetoacetate, acetone, and beta-hydroxybutyrate). 

What about athletes? 

Traditionally athletes have used carbohydrate sources such as maltose, dextrose, and others.  The entire industry of sports performance supplements has been geared to maximize carbohydrate absorption (max is about 240 kcals/hour due to GI function/absorption) and items are packaged in 80-100kcal/use servings.  So what happens to performance when you athletes switch to a keto diet?

Several studies have been completed looking at the short and longer (up to 3 months) use of keto-diets on performance. The results show ketosis seems to be better suited for endurance athletes than anaerobic athletes. In one study, short-term low-carbohydrate, ketogenic diets reduced exercise performance in activities that are heavily dependent on anaerobic energy systems (wroble, et al,m 2018). In another, a  low carb/keto-adaptated group of athletes had improved exercise training, lower body fat, improved fat oxidation during exercise, and better 100km time trial (McSwiney et al., 2018).

The bottom line is more research is needed, however, depending on the athletic activity, the keto diet may either help or harm athletic performance.

Contraindications: Individuals with inborn metabolic errors should NOT use the ketogenic diet.  Individuals with a history of documented myopathy or rhabdomyolysis should complete a more in depth workup for inborn errors prior to starting a ketogenic diet due to an increased risk of catabolic crisis.

References

• Kossoff, E. H., Zupec-Kania, B. A., Amark, P. E., Ballaban-Gil, K. R., Christina Bergqvist, A. G., Blackford, R., Buchhalter, J. R., Caraballo, R. H., Helen Cross, J., Dahlin, M. G., Donner, E. J., Klepper, J., Jehle, R. S., Kim, H. D., Christiana Liu, Y. M., Nation, J., Nordli, D. R., Jr, Pfeifer, H. H., Rho, J. M., Stafstrom, C. E., … International Ketogenic Diet Study Group (2009). Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group. Epilepsia, 50(2), 304–317. https://doi.org/10.1111/j.1528-1167.2008.01765.x
• Wroble, K. A., Trott, M. N., Schweitzer, G. G., Rahman, R. S., Kelly, P. V., & Weiss, E. P. (2019). Low-carbohydrate, ketogenic diet impairs anaerobic exercise performance in exercise-trained women and men: a randomized-sequence crossover trial. The Journal of sports medicine and physical fitness, 59(4), 600–607. https://doi.org/10.23736/S0022-4707.18.08318-4
• McSwiney, F. T., Wardrop, B., Hyde, P. N., Lafountain, R. A., Volek, J. S., & Doyle, L. (2018). Keto-adaptation enhances exercise performance and body composition responses to training in endurance athletes. Metabolism: clinical and experimental, 81, 25–34. https://doi.org/10.1016/j.metabol.2017.10.010

Most athletes love to win! Many factors impact your ability to perform at your best. Some factors are out of your control, such as heat, humidity, wind, altitude, terrain or playing surface, as well as the time of the event, amount of time between events, and perhaps jet lag. But nutritional factors are in your control, including what, when, and how much you eat. Simply put, to perform at your best, you need to know how to eat well enough to fight fatigue and be strong to the finish.

To address the how to eat to perform at your best issue, I looked to the highly respected sports nutritionist Louise Burke PhD. researcher at Australian Catholic University in Melbourne. Here are some key points from her journal article, Nutritional approaches to counter performance constraints in high-level sports competition. This information might inspire you to consult with a registered dietitian/ board-certified specialist in sports dietetics (RD CSSD) who can help you optimize your sports diet.

Eating

• Carbohydrate is a fundamental source of energy for your muscles. It is stored in your muscles as glycogen. Glycogen depletion (“hitting the wall”) is linked with fatigue.

• Carbohydrate is also a fundamental fuel for your brain. Carbohydrate in the blood, known as blood glucose, fuels the brain so it can focus on—and respond quickly to—the task at hand. To optimize athletic performance, you want to maintain adequate blood glucose levels during exercise, as well as start intense exercise with fully loaded muscle glycogen stores.

• Blood glucose gets supplied from your liver as well as from the banana, toast or other form of sugar or starch (carb) you eat before and/or during exercise. Some athletes avoid pre- and during-exercise carbs, fearing it will create intestinal distress. The better path is to train you gut to tolerate foods and fluids. By experimenting during exercise sessions with a variety of carbs (dried pineapple, granola bar, diluted juice) and/or a variety of flavors and brands of commercial products (sports drinks, gels, chomps, etc.), you can learn which fuels settle best. Choosing a variety of carbohydrates can increase the rate they are absorbed and might reduce the risk of GI distress. Having a well-tested fueling plan is helpful.

• Training enhances your ability to burn fat, and it can be further enhanced by adapting to a keto (high fat, very low carb) diet. Given fat stores are essentially limitless, a keto-adapted endurance athlete (theoretically) should be able to perform very well without having to consume additional carbs during exercise, reducing their risk of intestinal upset from drinking/eating during a race. Sounds good, but this theory doesn’t always work. Research shows that keto-adapted athletes can maintain their performance of moderate intensity exercise but experience a performance decline during real-life high intensity competitive endurance events. That’s in part because burning fat, as compared to burning carb, requires more oxygen and at high intensities, such as a break-away to the finish, oxygen supply to the muscle becomes a limiting factor.

Brain function

• Athletes need a well-fed brain to help them concentrate and make wise decisions. A well-fed brain can also help keep you motivated to exercise at a hard pace. To feed your brain, you want to embark upon exercise being well fed, with blood sugar in a normal range (blood sugar can drop overnight) and not be fasted and running on empty. Eat before you exercise!

• Caffeine is known to reduce the brain’s perception of pain, effort, and fatigue (even in athletes who regularly consume coffee). The recommended dose is 1.5-3 mg per pound of body weight (3-6 mg/kg) but one size does not fit all. Experiment to find the dose that’s best for your body.

• Athletes can consume caffeine via gels, caffeinated energy bars, pre-workout supplements, caffeine pills, and coffee. The problem with coffee is the variability of the caffeine content, which makes it hard to identify a specific dose.

• Some performance enhancers do not need to be absorbed into the body to offer beneficial effects. For example, simply rinsing the mouth with a sugar solution/sports drink (and spitting it out) stimulates reward centers in the brain, allowing you to work harder and enhance your performance.

• Rinsing the mouth every 5 to 10 minutes with a menthol-containing solution creates a perceived cooling effect that can help to increase power or speed during prolonged exercise in the heat. But be careful. If you feel cooler—but actually are not cooler, you might over-extend yourself and end up slowing down prematurely.

• Anti-cramping agents such as pickle juice, capsaicin, or spicy tastes might be helpful for athletes who experience muscle cramps. These pungent tastes are thought to “distract” the nerves involved with the cramping muscle and reduce the severity of the cramp. (More research is needed.)

Fluids

• You want to be sure you are optimally hydrated before you start competing. Your first morning urine should be light-colored, not dark and concentrated.

• Whether programmed drinking (according to a plan) is better than drinking as desired, according to your thirst, depends on your sport. For example, a marathon runner can develop a large mismatch between sweat losses and fluid intake. A 10-K runner is less likely to become severely dehydrated.

• The suggested goal is to lose <2% of your body weight over the course of the event (3 lbs. for a 150-lb. athlete). In lab-based research, a loss of >3% of body weight (4.5 lbs.) is linked to reduced performance. In real life, many athletes’ motivation to win over-rides the negative effects of being under-hydrated. Questions remain unanswered: Could underhydrated athletes have performed better If they were better hydrated? Or does being lighter due to dehydration offer an advantage? Stay tuned. Sports nutrition is an evolving science.

Nancy Clark, MS, RD counsels both casual and competitive athletes in the Boston-area (Newton; 617-795-1875). Her best-selling Sports Nutrition Guidebook is a popular resource, as is her online workshop. Visit NancyClarkRD.com for more info.

Reference: Burke, LM. Nutritional approaches to counter performance constraints in high level sports competition. Experimental Physiology, Nov 2021

As you may recall from nursery songs, Mares eat oats and Does eat oats—and so do many athletes. (FYI, the song is actually Mairzy Doats.) Questions arise about oatmeal:

• Is oatmeal beneficial for athletes? 
• Are steel-cut oats better than quick-cooking oats?
• Does oatmeal really “stick to your ribs”?
• And for some, “Why would any athlete even want to eat oatmeal?? It’s so gluey … yuck! 

Let’s take a look at what you might want to know about this popular sports food.

Oatmeal (aka porridge in parts of the world) refers to de-husked oats (groats) that have been cut into small bits (steel-cut) or steamed (to soften the groats), then flattened with rollers (rolled oats). Regardless of the way the groat is processed, all types of oatmeal are 100% whole grain and offer similar amounts of protein, fiber, vitamins, and minerals. What differs is the cooking time, shape (rolled or steel-cut), texture (chewy or smooth), and whether or not they are all natural or fortified with B-vitamins and iron.

Which type is best? The answer depends on your taste preference and available cooking time.

Steel-cut oats take 20 to 30 minutes to cook. They have a chewier texture than rolled oats. Some athletes use a crockpot to cook them overnight. Despite popular belief, steel-cut oats are nutritionally similar (not superior) to rolled oats.

Old-fashioned oats (rolled oats) cook in 5 to 10 minutes and have a firm texture. They can be eaten uncooked with milk, like any dry cereal, or in the form of muesli or overnight oats.

Quick-cooking oats are ready in a minute on the stovetop. Because they are rolled thinner than old-fashioned oats, they cook quicker and have a smoother texture.

Instant oats cook quickly in the microwave. They are pre-cooked, rolled thin, dried, and then rehydrated to be eaten.  They can be fortified (or not) with B-vitamins & iron. Some flavors are sugar-laden and perhaps best saved for dessert.

Benefits from eating oatmeal

• Oatmeal is one of the most affordable whole grains, perfect for hungry athletes on a budget. At least half your daily grains should be whole grains. Oats for breakfast give you a good start to reaching that whole grain goal for the day.
• Oats are a “safe” choice for a pre-event meal. They are low in certain fibers (referred to as FODMAPS) that send some athletes to the porta-toilets.
• Oats contain a type of soluble fiber (beta-glucan) that makes cooked oats gluey—but can be beneficial for endurance athletes. Beta-glucan slows the absorption of carbs over 2 to 3 hours, helping you feel satiated for a long time. Hence, oatmeal sticks to your ribs; it’s a good pre-exercise choice for sustained energy.
• Beta-glucan helps reduce the risk of heart disease if you eat oats in the context of a heart-healthy diet. To achieve this benefit, the daily target is 1 cup dry rolled oats or ½ cup dry steel-cut oats most days of the week.
• Oats have about 5 grams of protein per ½ cup dry serving. A good protein target for breakfast is at least 20 grams, so cook the oats in 1 cup milk (dairy milk, 8 g protein, or soy milk, 7g protein) and stir in 2 tablespoons of peanut butter or ¼ cup of nuts (8 g pro), and you’ll have a super sports breakfast!
• Fortified oats offer extra iron, a mineral important for athletes who do not eat red meat. A packet of plain Quaker Instant Oatmeal offers 40% of the DV for iron; regular oats offer only 6%. Read the Nutrition Facts label for information on iron in the oats you buy.
• Oats have some fiber, but only about 4 grams per serving (1/2 cup dry rolled oats, 1/4 c dry steel-cut oats). Given the daily fiber target is 25 to 38 grams (achieved by only 10% of women and 3% of men), oats make a small contribution—but more fiber than if you were to have just eggs for breakfast.
• Oats contain an antioxidant called avenanthramide (AVA). AVA can reduce the oxidative stress created by vigorous exercise. New research hints pre-exercise oatmeal might have a protective effect that could potentially reduce inflammation and muscle damage. Stay tuned.
• While naturally gluten-free, oats are often processed in a factory that also processes (gluten-containing) wheat. If you have celiac disease, you want to make sure you buy gluten-free oats (Bob’s Red Mill Oats, Quaker Gluten-Free Oats).

How to boost your oat intake

• Oats are versatile. You can cook them in water —or preferably in milk— to add protein, calcium, and creaminess. The suggested ratio is 1 cup (8 oz) of liquid for each half-cup rolled oats or ¼ cup steel-cut oats.
• For a savory option, cook oats in broth, season with soy sauce, or top with sriracha. Or add some cheese and spinach when cooking, then top the oatmeal with a poached egg.
• As an athlete, you lose sodium in your sweat, so don’t be afraid to make oatmeal tasty by sprinkling on some salt. A quarter teaspoon salt per ½ cup dry oats really helps change the bowl of glue into a yummier breakfast.
• Add sweetener, if desired, to make the oatmeal taste even better—honey, maple syrup, raisins, chopped dates. These extra carbs offer fuel for your muscles. According to the US Dietary Guidelines, 10% of daily calories can come from added sugar. That’s perhaps 200 calories (50 grams) of added sugar for an athlete—guilt‑free!
• Don’t have time to cook oats in the morning? Make overnight oats the night before! There’s no wrong way to make overnight oats. In a 16-ounce glass jar (such as a peanut butter jar), combine ½ cup old-fashioned oats, ½ cup milk, ¼ cup Greek yogurt, fruit-of-your choice (banana, berries), and optional add-ins, such as chia seeds and maple syrup. Refrigerate at least 2 hours for the oats to soften, if not overnight.
• Add rolled oats to a recovery shake or fruit smoothie for a thicker texture, as well as for more carbs to refuel your muscles.
• Bake with oat flour (blenderized oats). The Peanut Butter Chocolate Chip Muffin recipe from my Sports Nutrition Guidebook is a good pre-exercise energy booster and fun way to boost your oat intake. Enjoy!

Sports Nutritionist Nancy Clark, MS, RD counsels both casual and competitive athletes in the Boston-area. Her best selling Sports Nutrition Guidebook can help you eat for health and high energy. For more information about her books and online workshop, visit NancyClarkRD.com.

Did you decide to start eating a plant-based diet in 2022? No matter your reason—health, the environment, or animals—you’re making an excellent choice.

But now you may be wondering: How do I get stated? The good news is that eating a plant-based diet is easier than ever, and I’ve got a few tips to help you get started.  

Veganize your favorite foods

Going plant-based doesn’t mean you have to give up your favorite foods! Chances are, you’re already eating plenty of foods—like oatmeal, pancakes, burritos, chili, pizza, pasta, and even brownies—that are easily made plant-based by simply leaving out the meat and cheese and swapping dairy milk for plant milk. Prepared plant-based alternatives to burgers, chicken, sausage, cheese, eggs, etc., which you can find in many grocery stores, can also help ease your transition from animal products while you explore the wide world of plant-based meals.

Expand your palate

In addition to veganizing your favorite foods, make sure you have fun trying flavorful plant-based foods that may be new to you. There are countless plant-based cookbooks and online recipes to get you started. How about trying Thai Crunch Salad With Peanut Dressing, Farro with Miso Mushrooms, Kale, and Walnuts, or Lentil and Split Pea Soup with Fennel and Orange?

Stock up

Now it’s time to stock your shelves and refrigerator. Be sure to eliminate sources of temptation. It’s much easier to stay on track when you’re greeted by enticing healthful choices, rather than those you’re trying to leave behind. Use the recipes you’ve picked to make a grocery list of all the ingredients you’ll need. You might even find that you’ll save some money when you check out. Recent research shows that a vegan diet can reduce food costs by up to one third.

Dine out

Finding plant-based options while dining out is easier than ever. Happy Cow is an app and website that lists restaurants around the world with vegan options. You can also explore cuisines from around the world—like Chinese, Ethiopian, Indian, Japanese, Latin American, and Middle Eastern—many of which feature plant-based foods as staples. But if you end up at a restaurant that doesn’t appear to have a plant-based option on the menu, politely explain that you don’t eat meat, dairy products, or eggs, and ask the server if it’s possible to modify a menu item or for the chef to make something. They’re often glad to, depending on the ingredients they have. 

Take B12

Eating a variety of fruits, vegetables, grains, and beans provides all the essential nutrients your body needs. It’s also important to include a reliable source of vitamin B12 in your diet. You can easily meet your B12 needs with a daily supplement or fortified foods, such as vitamin B12-fortified breakfast cereals, plant milks, and nutritional yeast.

Talk to your doctor

At your next appointment, let your doctor know that you’re following a plant-based diet. If you’ve made improvements in your health, your doctor may be keen to hear what you’re doing! 

Get support

Dietary changes are more effective when you have consistent support or even a friend making the same changes along with you. Try reaching out to friends and family, meetup groups, social media groups, mentors or allies, or co-workers. 

Stay inspired

Keep learning about the benefits of a vegan diet with books, documentaries, and podcasts. I’ll share a few of my favorites. Book: The Vegan Starter Kit. Documentaries: Forks Over Knives, What the Health, and They’re Trying to Kill Us. Podcasts: Rich Roll and The Exam Room.

Take a class

The Physicians Committee has a wide range of classes. If fact, we’re launching One Healthy World on Jan. 13. The free program—taught in English, French, Spanish, and Mandarin—will revolutionize your health in six sessions, all free and on demand. We also offer in-person and virtual Food for Life classes around the world.

Download an app

The 21-Day Vegan Kickstart, developed by doctors, dietitians, chefs, and experts in vegan cuisine, features meal plans, recipes, and advice from nutrition experts.

Join Dr. Cullimore for his free webinar on this topic, Veganism 101: How to Eat a Plant Based Diet

Josh Cullimore, MD, MPH is director of preventive medicine for the Physicians Committee for Responsible Medicine, a Washington, D.C.-based nonprofit organization dedicated to promoting preventive medicine, especially better nutrition, and higher standards in research.