Quick Hit Summary
In Part II of this installment of “Interview with the Expert” we once again pick the mind of the highly respected vegetarian sports nutritionist Dr. D Enette Larson-Meyer, PhD, RD, FACSM. This time we examine the process of writing a book, her academic background as well as her research on caloric expenditure, vitamin D, dietary fat and endurance performance as well as other exciting research studies currently being conducted in her lab.
About Dr. D Enette Larson Meyer & Part I Recap
Dr. D. Enette Larson-Meyer, PhD, RD, FACSM.8
In Part I of this interview Dr. Larson-Meyer discussed her experiences as an applied sports nutritionist, considerations for the vegetarian athlete as well as some research regarding dietary hemp protein. If you have not checked out the article, I highly encourage you to do so by clicking here
Now for a little recap on Dr. D Enette Larson-Meyer’s background…
Dr. Larson-Meyer is an assistant professor of Human Nutrition at the University of Wyoming, where she also serves as director of the nutrition and exercise laboratory. Her research focuses on how nutrition and metabolism influence the heath and performance of active people. One of Dr. Larson-Meyer’s studies was spotlighted in a previous article (The Effect of Caloric Restriction and Exercise on Weight Loss and Heart Health) that appeared here at CasePerformance.
Dr. Larson-Meyer earned a BS in Dietetics while attending the University of Wyoming in 1987. During this time period, she also completed an internship at the US Olympic Training Center in Colorado Springs. Dr. Larson-Meyer then went on to receive her PhD in Nutrition Sciences from the University of Alabama in 1998. Dr. Larson-Meyer served as a sports nutritionist for the University of Alabama at Birmingham Athletic Department from 1995 to 2000, and she has consulted with numerous athletes throughout her career.
Dr. Larson-Meyer is a fellow of the American College of Sports Medicine and is past chair of the Vegetarian Nutrition Dietetic Practice Group. She has published numerous scientific and consumer articles, has been featured in publications like Vegetarian Journal, and has served as a chapter contributor to publications including the American Dietetic Association’s Sports Nutrition: A Guide for the Professional Working with Active People and the International Olympic Committee Medical Commission’s Volleyball (Handbook of Sports Medicine and Science). She has also written a full length book, Vegetarian Sports Nutrition, aimed at helping both competitive and recreational vegetarian athletes obtain their training goals.
A serious recreational athlete for close to 20 years, Dr. Larson-Meyer enjoys running distance events, cycling, and dancing in her spare time.
And with that, we continue on with Part II of this interview…
Writing a book
{Note to audience… The remainder of this conversation will focus on Dr. Larson-Meyer’s book Vegetarian Sports Nutrition. Please be aware that I have never read this book nor do I receive any sort of financial compensation for mentioning this book. The focus of this conversation is not to promote the book as much as it is to explore the process of writing a book. }
I must congratulate you on writing a research based book dedicated towards teaching vegetarians how to eat for optimal sport performance. Although I have not read it myself, I see that a great amount of effort and research went into the process. Eighteen pages of mostly peer reviewed scientific journal references <— That’s awesome!!! How did the opportunity to write this book come up?
I was approached by my publisher, Human Kinetics. It was not the best time but it was hard to say no.
I see that a lot of research went into writing that book (18 pages of mostly peer reviewed scientific journal articles!!). After writing numerous research based sports nutrition/exercise physiology articles, I realize that it can take a while to churn out high quality writing. From start to finish, how long did it take you to write the book?
It took an intense 6 to 8 months. It is important to note, however, that I had previously written two book chapters and several educational handouts on the topic and that I knew the scientific literature very well.
Let’s pretend that you were coming out with a 2nd version of the Vegetarian Sports Nutrition Book. In the four years since publishing the book, is there any new research or topics that you’d like to address that weren’t covered in the 1st edition? If so, could you give us a quick peak as to what they’d be?
There is a lot of new information on the importance of the branched chain amino acids on stimulating muscle protein synthesis following exercise. While soy protein is high in the branched chain amino acids, they do not appear to be as rapidly absorbed as branched chain amino acids in whey or whole milk. Casein interestingly is not as good as soy which is not as good as whey. I would definitely include discussion of this topic. I would also update the vitamin D section because we know a lot more about how vitamin D deficiency may impair performance—although we still have a lot to learn. There would be a few more things I would update here and there based on new research but this research simply supports what is already in the book.
For athletes considering a vegetarian or vegan lifestyle, what resources, other than your own book, Vegetarian Sports Nutrition, would you recommend?
- Vegetarian Journal. Bimonthly publication by the Vegetarian Resource Group, PO Box 1463, Baltimore, MD 21203. ISSN 0885-7636. http://www.vrg.org.
- Meatless Meals for Working People. Quick and Easy Vegetarian Recipes, 5th edition, by Debra Wasserman and Charles Stahler, Vegetarian Resource Group; 2009. ISBN 0-931411-29-7
- Simply Vegan, 4th edition, by Debra Wasserman and Reed Mangels, PhD, RD, Vegetarian Resource Group; 2006. ISBN 0-931411-30-0 224.
- Becoming Vegetarian by Vesanto Melina, MS, RD and Brenda Davis, RD, Healthy Living Publicationss; 2003. ISBN 1-57067-144-3.
- Becoming Vegan by Brenda Davis, RD and Vesanto Melina, MS, RD, Book Publishing Company; 2000. ISBN 1-57067-103-6
Exercise and Nutrition Research Experiences
Let’s switch gears a little bit and discuss your experiences in the academia field as an exercise physiologist and nutrition researcher…Have you always been interested in the research side of sports nutrition and exercise physiology?
When I look back at my past and my interest in reading summaries of research studies as a high school and undergraduate student it is fair to say that I was always interested. I recognized this interest (or passion) during my dietetic internship at Massachusetts General Hospital in Boston. I was assigned to complete a one-week rotation at the General Clinical Research Center. When I arrived, the research dietitian was busy with a patient so she asked me to go in the break room and read through the current research protocol book. I got so involved that eventually she came in to find what I was doing. I was fascinated by all of the studies and knew right then and there what I wanted to do.
What’s your favorite area of research?
I enjoy all clinical research. My favorite, however, is research related to the health and performance of athletes, particularly female athletes. Most recently, my passion has been research on vitamin D and human health. With the IOM report that recently came out, it appears that there will be plenty of opportunity to continue vitamin D research in the future. While I was a little disappointed in the RDA they set for vitamin D, it was a step in the right direction. I do agree that more research on vitamin D is needed.
I’ve found your research looking at dietary fat intake (10% vs. 35% of kcal intake), intromyocellular lipids (ie- fat stored within muscle tissue) and endurance performance in highly trained athletes to be very interesting12. If you could discuss the results of these studies for the readers here at CasePerformance, it’d be greatly appreciated.
In the first study we had trained female runners run at 67% of their maximal aerobic fitness (VO2max) for two hours and then consume a very low fat (10% fat) or a moderate fat (35% fat) recovery diet for three days in randomly assigned crossover fashion. We found that intromyocellular lipids (IMCL) fell by ~25% during the endurance run, and that IMCL recovery was dependent on the fat content of the post-exercise recovery diet. Specifically, IMCL recovered by 22-hours following exercise on the moderate fat diet and overshot baseline by 70 hours post-exercise. In contrast, IMCL stores did not return to baseline even by 70 hours of recovery on the low-fat diet.
In our second study—which was conducted in trained female and male runners—we basically repeated the first study to separate the IMCL stores and then had participants follow the low-fat diet (which was also very high in carbohydrate) in attempts to normalize glycogen stores between the two recovery diet regimens. The runners then completed a time trial on the following morning which consisted of a 90 min run at 62% of VO2max followed by a 10-k time trial. We hypothesized that the higher IMCL stores on the moderate fat diet would spare muscle glycogen during the lower intensity run (at 62% of VO2max) which would then allow the runners to perform better in the more intense time trial. We found, however, that there were no performance differences between the recovery diet regimens. This suggested of course that low IMCL stores do not compromise exercise—like low muscle glycogen stores do—at least during events lasting slightly over 2 hours.
Both studies, however, did find that the low fat diet resulted in unfavorable changes in lipid values specifically increasing fasting triglycerides and the total cholesterol to HLD-cholesterol ratio.
In theory, I would expect that decreased intromyocellular levels (as seen with the low fat diet) would deplete glycogen stores faster. Therefore, endurance performance would suffer. However this was not found by your research group2. As mentioned in your paper, higher pre-exercise glycogen levels in the low fat diet confound the results. Thus, I was wondering what your “gut” feeling is on the impact of intromyocellular lipid levels and performance?
My gut feeling is that it is that IMCL stores are an important fuel source during prolonged exercise lasting longer than we tested, i.e.. longer than 3 to 4 hours. It would be hard to repeat the study, under these conditions, however. My hope is that someone else will eventually conduct this study.
Previously on CasePerformance, we discussed your recently published research examining the Effects of Caloric Restriction and Exercise on Weight Loss and Heart Health. In previous private conversation, you mentioned that this specific study was part of a much larger project which was dedicated towards examining the effects of caloric restriction and/or exercise on aging and markers of health. Can you give us a brief synopsis of the “sister” studies that were part of this much larger project?
It is probably better to refer to it as the “parent” study with multiple arms. I was involved in these studies when I worked as the research exercise physiologist at the Pennington Biomedical Research Center. The study was a 6 month intervention study that was designed to be a pilot project to a 2-year intervention study that is currently in process at PBRC.
In the pilot study, 48 overweight male and female subjects were randomly assigned to one of four groups. One group received 25% calorie restriction by diet alone, another group was calorie restricted by the same degree by diet plus exercise – increasing energy expenditure by 12.5% and reducing intake by 12.5%. A third group received an extremely caloric restricted diet (890 calorie/day) until they reached the projected weight loss of the first two groups and the final group received no intervention (ie – a control group).
As the exercise physiologist, I monitored the exercise group and also performed measurements of liver and muscle lipid stores. Basically my collaborative work on this project found that calorie restriction, whether it included exercise or not, produced significant reductions in liver lipid and serum triglycerides3. While liver lipid stores and fat cell size were correlated with insulin sensitivity at baseline (before calorie restriction), the improvements in insulin sensitivity following six-months of calorie restriction were related to changes in total fat mass and visceral fat mass and not liver lipid stores4.
In a study published in Medicine and Science in Sports and Exercise at the beginning of this year, we reported data which showed that the calorie restriction plus exercise had greater improvements in blood pressure, lipid profile and insulin sensitivity than did the other treatment groups5. Specifically, significant decreased in diastolic blood pressure, total cholesterol and LDL-cholesterol and significant increases in insulin sensitivity were found only in the calorie restriction plus exercise group and not in the calorie restriction by diet alone group. By study design, weight loss in both groups was identical. Therefore these results highlight the importance of including exercise as part of weight loss of calorie restriction. Unfortunately the 2-year study calorie restriction did not include an exercise group.
Can you give us a sneak peak at the topics that your lab is currently studying?
Recent work in my laboratory has focused on vitamin D status in relation to illness and inflammation in athletes. Our work has shown that distance runners living in the southern part of the US (Baton Rouge, 30.5° N latitude) had a surprisingly high prevalence of deficiency6 —which was most likely related to the time of day they train—whereas college athletes living in Laramie (41.3° N) had a surprisingly low prevalence of insufficiency in the fall and spring (7). In the college athletes, serum Vitamin D stores (25-hydroxy vitamin D) dropped significantly during the winter months (when cutaneous synthesis of vitamin D is negligible due to the zenith angle of winter sunlight). Of greatest interest was that vitamin D insufficiency was correlated with increased serum concentrations of the whole body inflammatory marker tumor necrosis alpha, and an increased prevalence of wintertime illnesses (including upper respiratory tract infections, and gastritis).
Other work in my laboratory is focusing on how the hunger hormone ghrelin and the appetite suppressing hormones glucagon-like peptide (GLP-1) and peptide YY (PYY) are altered by exercise. We recently finished a study which evaluated whether ghrelin, GLP-1 and PYY were altered by a 1-hour bout of running or walking (at 70% VO2max) in habitual female runners and walkers, respectively. Preliminary findings suggest that increases in PYY following running but not walking may over-ride increases in ghrelin thereby at least partially explaining why appetite is commonly suppressed following certain types of exercise.
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That’s all the questions I have for you today. I realize that thoroughly answering these questions takes a lot of time and effort on your part. Thus, on behalf of the readers here at CasePerformance, I want to thank you for taking time out of your busy day to join us.
References:
1 Larson-Meyer DE, Newcomer BR, Hunter GR. Influence of endurance running and recovery diet on intramyocellular lipid content in women: a 1H NMR study. Am J Physiol Endocrinol Metab. 2002 Jan;282(1):E95-E106.
2 Larson-Meyer DE, Borkhsenious ON, Gullett JC, Russell RR, Devries MC, Smith SR, Ravussin E. Effect of dietary fat on serum and intramyocellular lipids and running performance. Med Sci Sports Exerc. 2008 May;40(5):892-902.
3 Larson-Meyer DE, Newcomer BR, Heilbronn LK, Volaufova J, Smith SR, Alfonso AJ, Lefevre M, Rood JC, Williamson DA, Ravussin E; Pennington CALERIE Team. Effect of 6-month calorie restriction and exercise on serum and liver lipids and markers of liver function. Obesity (Silver Spring). 2008 Jun;16(6):1355-62. Epub 2008 Apr 10.
4 Larson-Meyer DE, Heilbronn LK, Redman LM, Newcomer BR, Frisard MI, Anton S, Smith SR, Alfonso A, Ravussin E. Effect of calorie restriction with or without exercise on insulin sensitivity, beta-cell function, fat cell size, and ectopic lipid in overweight subjects. Diabetes Care. 2006 Jun;29(6):1337-44.
5 Larson-Meyer DE, Redman L, Heilbronn LK, Martin CK, Ravussin E. Caloric restriction with or without exercise: the fitness versus fatness debate. Med Sci Sports Exerc. 2010 Jan;42(1):152-9.
6 Willis KS. Vitamin D status & immune system biomarkers in athletes. Laramie: Family and Consumer Sciences, University of Wyoming; 2008.
7 Halliday T, Peterson N, Thomas J, Kleppinger K, Hollis B, Larson-Meyer D. Vitamin D Status Relative to Diet, Lifestyle, Injury and Illness in College Athletes. Med Sci Sports Exerc. Jun 11.
8 Image obtained Dec 11, 2010 from: http://uwadmnweb.uwyo.edu/family/Faculty/Larsen-Meyer.asp