Plant-Based Sports Nutrition

In Plant-based Sports Nutrition, registered dietitians Enette Larson-Meyer and Matt Ruscigno combine evidence-based research with personal experience working with – and as – vegan and vegetarian athletes to offer a complete explanation of how, when and why you need to plan your nutrient intake.

In the book Plant-based Sports Nutrition, you will learn how to get proper amounts of all essential macronutrients, vitamins and minerals while taking into account your personal calorific needs. It includes information on keto diets, tips for optimising bone health and iron intake.

Introduction
This book is designed to help you optimise your training, performance and health through better food choices. The book reviews the latest information on fuelling athletic performance and offers suggestions on how you – as a busy athlete – can easily

meet your energy, carbohydrate, protein, fat, fluid, and vitamin and mineral needs through a plant-based diet. It contains sections that allow you to assess your current diet and tailor your food choices according to your training and wellness goals.
In this extract we are looking at Chapter 5: Building Muscle Without Meat.
Although protein does play a critical role in an athlete’s health and performance, it can be adequately supplied by plant-based diets, including vegan diets. This chapter reviews the role of protein in the diet and discusses how you can easily build muscle strength and mass without meat.

Protein primer Dietary protein is necessary for sustaining life. It provides the amino acid building blocks needed to form the structural basis of most of the body’s tissue, including skeletal muscle, tendons, hormones, enzymes, red blood cells and immune cells. Amino acids also serve as a source of energy, and certain amino acids can be converted to blood sugar in a process called gluconeogenesis, which is important during both prolonged exercise and starvation. Chemically, each of the 20 different amino acids is structurally distinct, but all contain at least one nitrogen containing amino group attached to a similar skeleton of carbon, hydrogen and oxygen.

Our body’s requirement for protein is really a requirement for amino acids and nitrogen. As humans, we cannot produce nine of these amino acids – called the essential amino acids – but are able to make the remaining 11 or so as long as enough nitrogen is consumed in the diet. Together, the 20 essential and non-essential amino acids are arranged in various combinations to build the many proteins in the body. The arrangement of these amino acid building blocks is unique for each protein in the body as well as in the foods we eat. Closely related species, such as humans and animals, tend to make proteins with a similar spectrum of amino acids, and those of very different species, such as plants compared to mammals, tend to have quite different spectrums. Protein building is initiated after a signal – typically from a hormone or growth factor – to the cell’s genetic material (DNA) is communicated to initiate gene transcription and ultimately protein synthesis. In the case of exercise induced increases in skeletal muscle protein building (or synthesis), a key signal is a molecule called mammalian target of rapamycin (or mTOR), which is stimulated by both resistance exercise and the ingestion of dietary protein.
Although the body can make the nonessential amino acids, the essential amino acids must be obtained through the diet. If the mixture of the essential amino acids consumed in the diet does not match that required by the body, the amino acids found in the shortest supply, relative to the amount needed for protein synthesis, are referred to

The once-held belief that vegetarians needed to eat specific combinations of plant proteins in the same meal was dispelled in the 1990s.

*Guidelines established by the American College of Sports Medicine, the Academy of Nutrition and Dietetics, and Dietitians of Canada.

as the limiting amino acids. In general, diets based on a protein from a single plant food do not foster optimal growth because the single plant sources do not typically supply enough of all of the needed building blocks for human protein synthesis. For example, maize is low in tryptophan, rice is low in lysine and threonine, wheat is low in lysine, and most legumes, except soy, are low in methionine or tryptophan or both. Diets based on combinations of different plant proteins, as well as soy, dairy, fish, poultry or meat protein, however, can easily supply enough of the right amino acid building blocks for human growth and muscle development.

Determining protein needs
As an athlete, your protein needs are most likely – but not necessarily – higher than those of your inactive friends. Whether they are higher, and how much higher, depends on your sport and current training programme. For example, if you are a fitness enthusiast or a recreationally active athlete who exercises or plays sports several times a week, your needs are likely met by the recommended dietary allowance (RDA) of 0.8g of protein per kilogramme of body mass per day. The same may be true if you are taking time off from training or performing light maintenance training during the off-season. This is because the RDA is set two standard deviations above the estimated average requirement for protein of 0.6g of protein per kilogramme of bodyweight and is thought to meet the nutrient requirements of 97.5% of healthy individuals. If, however, you are training intensely for eight to 40 hours a week, your protein needs may be about twice the RDA, particularly during the start of the season or a new training regimen, or when muscle mass gain is important.
The consensus of sports nutritionists – which is based on published research on the protein needs of mostly male athletes – suggests that athletes need 1.2-2g of protein per kilogramme of body mass per day. While there is some thought that female athletes may require

slightly less protein per kilogramme of body mass than male athletes, more research is needed before sex-based recommendations can be made. The rationale for the additional protein required during training is based on the additional amino acid building blocks needed to promote muscle protein synthesis, repair exercise-induced microdamage to muscle fibres (endurance athletes know about this) and stimulate synthesis of enzymes and other proteins in our cell’s energy-generating powerhouses: the mitochondria. Thus, additional protein is needed for both strength and endurance training. Recent research has also suggested that protein may be needed not only as building blocks but also as a trigger to induce protein synthesis as a result of the signalling molecule mTOR. The amino acid leucine is thought to serve as this key signalling trigger.
In addition, inadequate intake of both energy and carbohydrate increases protein needs. During prolonged endurance activity, athletes with low glycogen stores use twice as much protein as those with adequate stores, primarily because amino acids are converted to glucose under these conditions to maintain blood sugar. This, however, can be halted by adequately supplementing with carbohydrate before or during exercise or both (as will be discussed in chapter 9). Furthermore, athlete or not, your protein needs are likely to be higher if you intentionally restrict calories to promote weight or body fat loss (as further discussed in chapter 13).
Although no research suggests that protein recommendations are different for vegetarian athletes, it has been suggested that vegetarians may need to consume approximately 10% more protein than omnivores to account for the lower digestibility of plant protein compared with animal proteins. However, the additional requirement to account for lower digestibility is not true for all plant proteins. The protein in most soy products, for example, is readily digestible compared to protein from whole, cooked legumes, which is not as easily digested.

Furthermore, in its release of the dietary reference intake (DRI) for protein, the Food and Nutrition Board of the National Academy of Sciences Institute of Medicine concluded that a separate recommendation for protein consumption was not required for vegetarians who consume complementary mixtures of plant proteins and certainly eggs or dairy products.
Finally, it is important to mention that not all scientists believe that the protein needs of athletes are higher than those recommended for the general population. Although many studies show that protein use, and therefore requirements, increases with the initiation of exercise training, most of these studies have been short term and may not have allowed enough time for adaptation to the training regimen. Hence, it is possible that the protein needs are only temporarily elevated and return to baseline at some point after training initiation and adaptation. For instance, a long-term study conducted in the early 1970s found that individuals starting a cycling programme experienced a negative nitrogen balance with initiation of training, indicating that their protein needs were increased above that of their sedentary state, but this negative nitrogen balance returned to neutral after 20 days of training with no change in diet. In the recent release of the DRIs, the scientists on the panel did not feel there was enough compelling evidence to suggest that additional protein is needed for healthy adults undertaking resistance or endurance exercise. An abundance of research conducted since the previous edition of this book was published, however, has underscored the importance of additional, well-timed protein intake in athletes to help build and repair muscle protein, which includes both muscle fibre proteins and mitochondrial proteins. The specific timing of protein intake relative to resistance or aerobic exercise is discussed further in chapter 9. You can estimate your overall daily protein needs using the calculations in Table 5.2.

Data compiled from the Diabetic Exchange List for Meal Planning, 2003; USDA National Nutrient Database for Standard Reference (https://ndb.nal.usda.gov/ndb/); and selected food labels, including those from Quorn, Calorie King Australia, and Impossible Burger.

Meeting protein needs
Despite the controversy over the protein needs of vegetarians and athletes, you can easily meet your protein needs – even if they are in the upper level recommended – on a plant-based diet. This, of course, is provided that your diet contains both adequate energy and a variety of plant-based protein foods.
The once-held belief that vegetarians needed to eat specific combinations of plant proteins in the same meal was dispelled in the 1990s, at least among non-athletic adults, and replaced with the recommendation to simply consume a variety of plant-based, protein rich foods over the course of a day. Emphasising amino acid balance at each meal is not necessary because the limiting amino acids in one meal can be buffered (at least over the short term) by small pools of free amino acids in the gut, skeletal muscle and blood. These amino acids come from the food consumed in the previous meal or snack and from the digestion of our own digestive enzymes and dead gut cells (which are sloughed off much like skin cells). Furthermore, although most plant foods tend to be low in certain amino acids (as discussed earlier), usual combinations of plant-based proteins consumed in the diets of most cultures –such as beans and rice – naturally provide complementary mixtures of the essential amino acids. As such, many combinations of plant-based proteins provide a source of high-quality protein (see Table 5.3). In addition, for vegetarians and semi-vegetarians, consuming small amounts of dairy, eggs, fish or poultry can also provide complementary essential amino acids, which can enhance the quality of plant proteins. If you are concerned about your own protein intake, you can check yourself by counting your protein intake for a day or two using the information provided in Table 5.4.

Reference

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