Plant-based running nutrition
Evidence: moderate
A well-planned vegetarian or vegan diet neither helps nor harms endurance performance in itself; when energy and nutrients are adequate, it performs like an omnivorous diet. The “vegan makes you faster” claim is not supported and rests on confounded comparisons. The real work is planning: enough total energy and protein, and deliberate attention to B12, iron, omega-3, creatine and a few other nutrients.
Not medical advice
This is a general knowledge base, not medical or dietary advice. If you are injured, unwell or weighing up a supplement or a change to your diet, speak to a doctor, physiotherapist or registered dietitian who knows your situation.
A vegetarian diet is a viable, evidence-adequate choice for endurance runners. A systematic review found no difference in strength, power, or aerobic or anaerobic performance between vegetarian and omnivorous athletes (Craddock et al. 2016), and the dietetic profession’s formal position is that appropriately planned vegetarian and vegan diets are adequate for athletes (Academy of Nutrition and Dietetics 2016). The qualifier “appropriately planned” carries the weight.
The popular idea that going plant-based is itself an endurance advantage does not hold up. Where vegan or vegetarian runners look faster in surveys, the comparison is confounded by training, body mass and health behaviour; the large NURMI cohort’s authors caution against reading diet-group differences as causal (Wirnitzer et al. 2022), and controlled comparisons of performance markers show no diet effect (López-Moreno et al. 2023). The honest framing is neutral-with-conditions: no edge from the diet itself, no penalty when it is planned well.
What to plan for
- Energy and protein. Under-eating total energy is the main risk and feeds Relative Energy Deficiency in Sport. Plant proteins are lower in digestibility and amino-acid quality, so the same available protein needs a higher total intake; in one athlete sample vegetarians had to eat roughly 10 g more protein a day to match omnivores (Ciuris et al. 2019). Spread protein across the day from varied sources and aim a little above the usual targets (see protein and recovery and daily carbohydrate and energy).
- Vitamin B12. Effectively absent from unfortified plant foods, since plants do not make it. Reliable supplementation or fortified foods are non-negotiable for vegans; deficiency causes anaemia and fatigue that directly cut endurance (Niklewicz et al. 2023).
- Iron. Plant (non-haem) iron is less bioavailable, so requirements are higher, and female runners are the highest-risk group; pair iron-rich plants with vitamin C and have status checked rather than blind-supplementing (see iron).
- Omega-3. Conversion from plant ALA to EPA and DHA is poor, so an algal-oil supplement is the practical plant-based route to marine omega-3 status (see omega-3).
- Creatine. Vegetarians have lower resting muscle creatine and so respond more to supplementation than omnivores (Kaviani et al. 2020; see creatine).
- The rest. Vitamin D, calcium, zinc and iodine round out the at-risk list in a poorly planned plant-based diet (see vitamin D and calcium).
The bottom line: plant-based running works, and brings the general health-pattern benefits of such diets, but it asks for deliberate planning rather than delivering a performance shortcut. How any of it suits you is individual (individual variation).