Estimated reading time: 7 minutes
By Tiffany Bruno, MS, RDN, Director of Education at Switch4Good
When people consider removing animal products from their diet, protein is often a big concern. This is heightened in athletes, who generally have greater protein and calorie needs to support their training and recovery. Although we’ve seen plenty of plant-fueled athletes win Olympic medals and achieve other major successes in their sports, many people are still skeptical.
While research has shown the notion of plant-based athletes underperforming is false, we are always making sure to stay on top of the latest research. After all, new research can debunk previous thoughts. Three new modeling studies were published this year addressing different concerns of athletes following a plant-based diet. Spoiler alert: athletes can get everything they need! Keep reading to learn more about energy, protein, leucine, and micronutrient intake in plant-based athletes.
First Off, What is a Modeling Study?
Modeling studies are a form of original research, but different from other types such as randomized control trials; there are no participants who are altering part of their diet to test its effects. In modeling studies, the researchers use computer models to mimic real-world situations and run simulations that might otherwise not be possible. This allows for data analysis without using participants, which can be cost-prohibitive and have other flaws.
Modeling studies are considered theoretical evidence, and they can help answer scientific questions and provide supporting information. They are especially useful in nutrition studies where every food has a different effect on the body, making it challenging to account for all of the confounding factors. If a food is added to the participants’ diet, what is the control group getting to make sure their energy is still matched, and what effect does that addition have? By using computer models, the researchers are able to better control the inputs.
Athletes Have Higher Energy and Protein Requirements
There’s no debate that most athletes have higher energy, or calorie, needs. They need more fuel to keep up with their running, lifting, training, and overall physical activity. To put it simply (because there are many more factors to consider), the more activity performed, the more energy the athlete requires.
Protein is always a hot topic among everyone from fitness junkies to dieters. Although most people overestimate their needs, athletes definitely have higher needs than non-active folks. Depending on their intensity and other factors, athletes should aim for 1.0 – 2.0 g/kg/day to meet their needs.
What About Leucine?
For athletes who have taken a deeper interest in nutrition and optimal fueling strategies, leucine is another hot topic. Leucine is an amino acid that serves as a building block and signaling molecule for muscle protein synthesis. It’s found in all foods, but some sources are proportionally higher than others, similar to any nutrient.
Previous research suggests a minimum of 2 g of leucine per meal is required to maximize muscle protein synthesis, with plant- and animal-based sources having similar anabolic effects at this quantity. However, critics of plant-based diets are still disillusioned to think they fall short on leucine. This new research will suggest otherwise.
Breaking Down the Research
The three studies looked at male bodybuilders, football players, and rugby players. First, their energy needs were calculated to be used for scaling the model. Then, protein and leucine goals were calculated. All three studies used dietary data from the Adventist Health Study-2 for the modeling because it included the largest sample of participants following a vegan diet.
Determining Energy Requirements
The three studies used slightly different methods to calculate energy requirements based on available research in each sport. The bodybuilders used a newly developed resting metabolic rate (RMR) prediction equation determined to be most accurate in male bodybuilders (4239 kcal/day). The football players had different daily calorie goals based on position: defensive lineman (6250 kcal), offensive lineman (6350 kcal), running back (5850 kcal), tight end (6150 kcal), linebacker (6050 kcal), and quarterback (5300 kcal). Lastly, the rugby players’ energy needs were calculated from previous research using doubly labeled water in collision team-sport athletes (4587.5 kcal/day). The models were each scaled to meet these respective energy goals.
Meeting Protein Requirements
As previously mentioned, athletes typically have higher protein requirements. The researchers set a protein goal of 1.6 g/kg/day for all three types of athletes based on published guidelines form the International Olympic Committee, as well as the sports nutrition textbook published by the Sports, Cardiovascular, and Wellness Nutrition Dietetics Practice Group of the Academy of Nutrition and Dietetics. This amount appears to maximize gains in muscle mass and strength.
The studies found all three types of athletes met or exceeded their protein needs. The bodybuilders’ model calculated protein at 1.8 g/kg/day. The football players had a range from 1.6 – 2.1 g/kg/day. The rugby players came in at 1.68 g/kg/day.
These findings substantiate that scaled plant-based diets satisfy protein requirements for maximizing resistance exercise training-induced gains in muscle mass and strength. If athletes who follow a plant-based diet consume enough calories, they will naturally consume enough protein as well.
Meeting Leucine Requirements
Leucine is crucial for building muscle, strength, and recovering properly. The researchers used values based on previously published research that surpassed average requirements suggested for maximal increases in muscle mass, strength, and muscle protein synthesis. This was determined to be 2 g/meal, or 8 g/day split over four meals.
All three types of athletes were able to exceed their leucine goal. The bodybuilders’ model calculated 2.75 g/meal, the football players’ ranged from 3.8 – 4.1 g/meal, and the rugby players’ calculated 2.9 g/meal. These findings indicate the plant-based diets surpassed the leucine threshold for stimulating muscle protein synthesis.
Micronutrients
Micronutrients were also analyzed based on athletes’ scaled requirements. The bodybuilders and rugby players fell short of their needs for vitamin D (but football players met their requirements). Inadequate vitamin D intake is a common problem among athletes and non-athletes alike, as well as animal- and plant-based eating patterns. A supplement is often required to prevent deficiency.
All three types of athletes surpassed their sodium recommendations. While high sodium intake is linked to increased risk of cardiovascular disease, athletes also have higher sodium requirements to replace electrolytes lost through sweat. More research is needed to understand whether elevated sodium intake is problematic in athletes.
Modeling Study Limitations
Modeling studies are not flawless. When using computation modeling to quantify dietary consumption, rather than relying on direct laboratory methods, there is potential to introduce variations between theoretical and observed levels. For example, dietary fiber can increase satiety, which may lead to athletes naturally consuming less food. Physiological cues like hunger and fullness, as well as factors that can affect those such as stress and sleep quality, are not accounted for in models. In reality, athletes may face challenges meeting these needs (which is true when energy needs are high in any population, not just plant-based eaters).
What To Do With The Information?
We often discuss the health benefits of a plant-based diet, such as reducing your risk of cardiovascular disease and hormonal cancers, and improving your digestion and respiratory function. And of course, we talk about a plant-based diet’s benefits for athletic performance.
These studies further confirm that plant-based diets can meet an athlete’s requirements to fuel their performance and recovery, while simultaneously reducing their risk of chronic diseases. For anyone looking to improve their performance, whether in their everyday life or at the elite athlete level, they can benefit from switching to a completely plant-based diet and still meet their nutrient needs.
If you’re still not convinced, just take a look at some professional athletes such as Nimai Delgado (bodybuilding), Derrick Morgan (football), and Mirco Bergamasco (rugby). These champions will quell any of your outstanding doubts!
If you’re looking to continue digging into the nitty gritty science of a plant-based diet for athletes, check out our book: Let the Plant-based Games Begin!
