Conference Highlights: PINES 10 Questions / 10 Experts Session at ACSM
Written by: Nancy Clark MS RD CSSD
At this year’s American College of Sports Medicine (ACSM) Annual Meeting (May 30-June 2, 2023, Denver, Colorado), PINES hosted its annual lively 10 Questions / 10 Experts session. Each speaker concisely addressed a current trend, myth, or misinformation. Below is a summary of the key points.
Continuous Glucose Monitors
Jamie Whitfield, Mary McKillop Institute of Health Research, Australian Catholic University, Australia
A continuous glucose monitor (CGM) can help athletes determine the best fueling tactics to maintain their blood glucose levels within an energizing range and ideally reduce needless bonking. This can be very helpful during endurance exercise such as marathons or long cycling events.
Unfortunately, CGMs have yet to be perfected for athletes. The monitors can easily get dislodged from the body and some studies show a >15% failure rate. The monitors measure just what’s happening with the blood, but not what’s happening in the muscles. The sport of cycling has banned CGMs during events, but many cyclists use them during training, to learn how to “read” body signals.
Pre-sleep protein
Michael Ormsbee, Florida State University and Institute of Sports Sciences & Medicine, USA
While extra evening protein is unlikely to offer a winning edge, it also will not cause harm, nor will it convert into body fat. Research to date shows that pre-sleep protein simply allows another opportunity to meet daily protein goals. In addition, pre-sleep protein has been shown to improve body composition index when used to simply add more total daily protein to the diet. More research is needed to determine if consuming pre -sleep protein will help enhance muscle recovery and repair, sleep, or performance.
Free amino acids, bioactive peptides and collagen
Stu Phillips, McMaster University, Canada
When compared to the protein in whole foods, free amino acids are slightly less effective for muscle protein synthesis. Consuming protein within its natural food matrix is best. Plus, free amino acids taste terrible (although they have improved over the years).
Bioactive peptides (2-3 amino acids linked together) are available to purchase but they lack research to validate any potential benefits.
Collagen research is commonly done by collagen companies. Research to date questions the effectiveness. When taken for skin and nails, just how does the collagen know where to go???
Bicarbonate supplementation
Jason Siegler, Arizona State University, USA
With high-intensity sports, sodium bicarbonate might offer a 1% to 2% improvement in performance. The standard dose is 0.3 to 0.5 g/kg body weight; the higher the dose, the greater the increase in performance—as long as the athlete can tolerate it. Capsules that bypass the gut help resolve gastro-intestinal issues, and potentially encapsulated in a gel may help even provide further protection form side effects.
Another option that bypasses the gut is sodium bicarbonate in the form of a lotion. The athlete applies it 20 minutes before high intensity exercise. The lotion is thick and feels nice, but recommending a specific dose is difficult because the amount that actually gets absorbed is unknown.
The lightest athlete is the best athlete (plus looks better in tight-fitting uniforms).
Nancy Clark, Sports Nutrition Services LLC, Boston, USA
While lighter and leaner “works” to a certain extent to enhance performance, the cost of being too light and too lean can take its toll. The less food an athlete consumes, the less protein, carbohydrate, fat, vitamins, and minerals the athlete consumes. This can hurt performance and recovery, while enhancing the risk of getting injured.
A study with elite race walkers reported no performance benefits (nor detriments) among the dieting athletes in a training camp who lost 2 kg the two weeks before a 10K race. The dieters and the non-dieting control group both carb-loaded in the 24-hours pre-race. They both performed similarly, with no significant benefit gained by having lost 2 kg pre-race. The moral of the story: athletes want to fuel well to support optimal performance, instead of dieting to be lighter.
Carbohydrates
Trent Stellingwerff, Canadian Sports Institute Pacific, Canada
Despite popular belief, endurance athletes who consume a sports diet rich in quality carbohydrate do not “get fat” nor become diabetic. The advice to limit carbs might be appropriate for unfit people, but fit athletes preferentially metabolize carbs and convert them into a winning source of muscle fuel.
Iron supplements
Alannah McKay, Mary McKillop Institute of Health Research, Australian Catholic University, Australia
Iron supplements are better absorbed at 6:00 a.m. than 11:00 a.m., and therefore taking iron first thing on an empty stomach appears best. That said, iron is known to contribute to stomach upset, and some athletes cannot tolerate iron if taken without food. For them, the best time to take iron is either prior to, or 30 minutes after exercise, before the post-exercise elevation in hepcidin (a hormone that hinders iron absorption) triggers a negative effect. If an athlete takes an iron supplement two hours after a hard exercise session, the elevated hepcidin concentration can reduce iron absorption by about 36%.
Sustainable sports diets
Nanna Meyer, Colorado State University, USA
Athletes need good food to perform, which depends on a healthy biosphere, including clean water. Sports dietitians can introduce athletes to global dietary guidelines that integrate the UN Sustainable Development Goals. By honoring those goals, athletes can become positive role models for living a sustainable lifestyle. That means: eating adequate but not excessive protein, consuming at least one-third of protein from plants, minimizing food waste (for example, after team buffets, by taking home the leftovers for the next day’s lunch), eating locally-grown foods (to reduce transportation emissions), and choosing foods with minimal and bio-degradable packaging (no Styrofoam, please). A sustainable athlete does not need to be vegan but does want to be mindful about dietary choices.
Vegetarian athletes
Enette Larson-Meyer, Virginia Tech, USA
Why do vegetarians have a reduced risk of chronic diseases? Is it because of eating less red meat? Or eating more plants? Plants are rich in phytochemicals (reduce inflammation), dietary nitrates (improve blood flow), and many other performance-enhancing nutrients. While a vegetarian diet imparts no obvious benefits for performance, it also imparts no detriments (as long as it nutritionally adequate).
On the other hand, meats-eaters have easy access to excellent sources of protein, B-12, iron, and zinc, all in a form that is easily absorbed. For meat-eaters looking for a path towards vegetarianism, enjoying a plant-based diet with just small amounts of meat (preferably that has been sustainably raised) can pave the way, as can honoring Meatless Monday (https://www.mondaycampaigns.org/meatless-monday). Small steps can have a big environmental impact.
Alcohol
Floris Wardenaar, Arizona State University, USA
BORG (Blackout rage gallon) drinking, in case you are not familiar with this trend, is a mixture of water, alcohol, sweet flavorings, and electrolytes (which supposedly offer the hangover remedy) in a one-gallon plastic jug. The concoction is popular on some college campuses, easy to drink, and easy to overconsume. An ounce of alcohol takes about one hour to breakdown; too many ounces can hinder training and performance, as well as sleep.
About the author: Nancy Clark MS RD CSSD has a private practice in the Boston-area. For information about her best-selling Sports Nutrition Guidebook and her online workshop, visit nancyclarkrd.com
