Vegan and plant-based diets are big news right now. Everyone seems to be eating less meat and more veg, part of the time at least, thanks to meat free Monday and other projects and hashtags. Several athletes, including the ultra-marathon runner Scott Jurek, have attributed their outstanding performances to their vegan diet. But just because a vegan diet works well for some athletes does that mean we would all be better off going vegan? What evidence is there that a fully plant-based diet improves athletic performance?
There has actually been very little research undertaken so far on the impact of vegan diets on athletic performance, though this is likely to change as Veganism continues to gain in popularity. From the studies done so far exercise performance does not appear to differ between dietary groups, despite some differences in macro- and micro-nutrient intake.
As with all things nutrition, what suits one person does not suit another. Genetics, training schedule and lifestyle all play a role in how well a plant-based diet suits each individual.
However, one important thing to acknowledge with a vegan diet is that it needs to be well-planned in order to meet the levels of essential nutrients needed. Research indicates that the average vegan diet has a higher nutritional quality than a meat-based diet, but only if well thought out. A poorly planned vegan diet could predispose athletes to deficiencies in protein and omega-3 essential fats as well as some vital micronutrients such as iron, zinc, B12, calcium and Vitamin D. The same research also found that less well-planned vegan diets can lead to reduced strength and endurance performance, depressed immune function, slower recovery and limited training adaptations.
If you do decide to follow a vegan diet there are some important nutritional considerations:
Consider your energy intake:
Weight loss commonly occurs in athletes transitioning to a vegan diet. Primarily due to the high fibre content which leads to feeling much fuller more quickly, in addition to plant-based foods taking up room in the stomach without providing many calories.
The solution is to eat more energy-dense plant foods such as olive oil, nuts and nut butters, seeds and avocados.
Sceptics of vegan diets always cite lack of protein as a reason not remove animal products from the diet. True, plant-based proteins are usually incomplete as they lack at least one of the essential amino acids, however this is easily resolved by eating pulses/legumes/nuts with grains.
Two examples are rice and beans or lentils and porridge with nut butter.
Good sources of plant-based protein include quinoa and oats, beans, lentils, pumpkin and sunflower seeds, and tofu.
Soaking or using sprouted beans, nuts, seeds and legumes reduces phytic acid content. This is important as phytic acid binds to magnesium, calcium, zinc and iron, thereby reducing absorption of these vital minerals.
Vitamin B12 is naturally found only in animal food sources. There are some fortified foods suitable for Vegan's, such as breakfast cereals, some plant-based milks and nutritional yeast, however many people who choose to eat a vegan diet do not consume processed cereals, choosing instead more foods in their natural whole state. Seaweed in the form of nori sheets contains some vitamin B12 and can be easily added to meals or eaten as a snack.
Vitamin B12 is important for well functioning nerve cells and cognitive function, in addition to benefiting heart health by lowering homocysteine levels. Raised levels of homocysteine, an amino acid, are associated with an increased risk of stroke and heart disease.
Studies show that vegans (due to not eating dairy products) do not generally consume sufficient calcium, which impacts bone mineral density and increases risk of stress fractures. However, there are some good plant-based food sources of calcium so with some planning it is perfectly possible to get your calcium requirements through plant foods.
Leafy greens (such as kale, broccoli and bok choy), beans and pulses, sprouts, tahini, calcium-set tofu and fortified plant-based milks contain good quantities of calcium.
In summary, a well-planned vegan diet could enhance health and athletic performance but there are no guarantees. Many factors and nutritional considerations need to be taken into account before deciding to follow a vegan diet, otherwise you run the risk of under-performance and reduced health.
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Helen Morton, registered Nutritional Therapist. sports nutritionist, runner, Level 2 Fitness Instructor and food lover, sharing latest nutrition research and recipes.