In 1977, American nutritionist Ancel Keys’ colleague Margaret Keys continued the discussion on lower-fat, plant-based diets – part of a movement that emerged in the post-war period and has had a lasting impact on nutritional research. Concurrently, pioneering athletes like Kathrine Switzer demonstrated that endurance performance is not just about will and training, but also involves smart nutrition. Today, it is evident that plant-based proteins can provide more than just "enough" – they can measurably support endurance athletes.

Those who train for endurance continuously consume glycogen and put stress on their muscles, bones, and immune system. Protein not only provides building blocks for muscle protein synthesisbuilding and repair of muscle tissue, but also stabilizes energy homeostasisbalancing of energy intake, storage, and expenditure and supports recovery. Plant proteins differ: they often have lower bioavailabilityproportion of ingested nutrients that actually reach the body and a different amino acid profilecomposition of essential amino acids compared to animal sources. This is not a disadvantage when planned wisely: combinations such as grains plus legumes complement limiting amino acids (e.g., lysine vs. sulfur-containing amino acids) and enhance overall quality. Importantly, micronutrients like calcium, vitamin D, and zinc are essential for bone density, immune function, and performance stability – they warrant special attention in plant-based diets.

For endurance athletes, it matters whether plant protein contributes to performance and resilience. Meta-analyses show that plant proteins improve performance and strength compared to no or low protein intake; when directly compared to whey or milk protein, effects are slightly smaller but still positive and relevant in practice ^[1]. Specific sources provide additional benefits: quinoa proteins increased endurance time in experiments, improved energy metabolism, and enhanced antioxidant capacity – indications of anti-fatigue effects that are crucial for long sessions ^[2]. Lentil protein isolates, in contrast, show higher digestibility and reduced anti-nutrients compared to whole flour, which may facilitate protein utilization ^[3]. At the same time, evidence warns: insufficient calcium and vitamin D intake increases the risk of lower bone density – a critical point with high running volumes; the good news is that with better planning, vegetarian patterns increasingly compensate for this disadvantage ^[4]. Zinc is also relevant: frequent deficiencies weaken antiviral defense mechanisms; targeted zinc supplementation has been shown to restore function ^[5].

A recent meta-analysis of randomized studies compared plant protein supplements with low or no protein intake as well as with animal proteins. The result: Compared to low/no protein, plant proteins measurably enhance endurance performance and muscle strength; compared to whey, milk, or beef protein, the effects are slightly lower but consistently positive. For endurance athletes, this means: Plant-based strategies work – they do, however, require precise planning to secure amino acid quality ^[1]. Additionally, experimental research on quinoa protein shows that specific peptides activate both energy metabolism (gluconeogenesis and mitochondrial biogenesis) and antioxidant systems – mechanisms that can dampen fatigue and extend time to exhaustion ^[2]. On a practical nutritional level, an optimization analysis demonstrates how a smart blend of plant protein sources maximizes protein quality (PDCAAS) while simultaneously covering critical micronutrients like calcium, iron, and zinc; particularly effective are sufficient portions from legumes and soy, complemented by grains, nuts, and seeds ^[6]. Finally, clinical data on micronutrient supply indicate that zinc deficiency under purely plant-based diets can weaken the innate immune system; supplementation normalized interferon-mediated defense – relevant for athletes who are prone to infections and need training continuity ^[5].

- Increase quinoa intake: 3-5 portions per week as a base for bowls, porridge, or as a side dish. Use quinoa right after long sessions with fruit and a protein source (e.g., soy yogurt) to replenish glycogen and kickstart recovery. Evidence for anti-fatigue effects supports a place in endurance meal prep ^[2].
- Incorporate lentils daily: red lentils for quick soups, beluga lentils for salad toppings, lentil pasta for carbohydrate-rich recovery meals. If sensitive to FODMAPs, occasionally opt for lentil protein isolates or well-soaked/fermented products - better digestibility, fewer anti-nutrients, high protein utilization ^[3].
- Combine protein sources for a complete amino acid profile: pair legumes (lentils, chickpeas) with grains (quinoa, brown rice), plus soy or lupin. Aim over the week for mixes of 10-30% grains/nuts/seeds and 40-60% legumes, supplemented by 30-40% soy products – this enhances protein quality and micronutrient coverage ^[6]. This boosts training tolerance and performance, as suggested by the meta-analysis on plant proteins ^[1].
- Pay attention to micronutrients: cover calcium (fortified plant drinks, tofu with calcium sulfate, kale) and vitamin D (supplement in dark seasons) for bone health ^[4]. Check zinc (whole grains, beans, nuts) and consider moderate supplementation based on blood values during high-intensity or vegan diets – important for robust immune responses ^[5].
- Optimize timing and amount: target 1.6-2.2 g protein/kg body weight/day under high endurance load; distribute 3-5 portions of 0.3-0.4 g/kg throughout the day, including post-workout. Use processed, well-tolerated variants (e.g., fermented soy, lentil, or oat products) during intense training phases to increase bioavailability ^[7].

Plant-based proteins are transforming from a "stopgap" to a strategic tool for endurance performance – supported by smart combinations, functional sources like quinoa, and precise micronutrient management. In the coming years, improved plant protein isolates and fermented products will further enhance bioavailability and connect personalized nutrition plans with data from blood values and wearables. The result: sustainable performance with strong health.