Is Too Much Protein Bad for You?

As triathletes, we aim to optimise performance, recovery, and overall health. Your daily nutrition is vital to achieving peak performance. Protein is a critical macronutrient in this equation. However, recent media reports have raised concerns about the potential negative impact of high protein consumption. In the world of endurance sports, triathletes historically tend to under-consume protein. Does this mean consuming less protein is a benefit to you? Are there benefits of a moderate to high protein intake? In this article, I will explore the role of protein in training, review the scientific evidence on protein consumption, and highlight how Fuelin, using Scooter, our AI food tracker, helps Fuelin users optimise their protein intake for health, performance and recovery. 
‍

The Role of Protein in Training and Recovery

Protein is the building block of muscle tissue. It plays a critical role in muscle repair, recovery, and adaptation to training, essential components of a triathlete’s program—your muscles, whether swimming, cycling, or running, are continuously stressed and broken down. Without adequate protein, your body cannot repair these tissues effectively, potentially leading to reductions in lean mass, fatigue, decreased performance, and a higher risk of injury. Moreover, protein supports a range of other bodily functions crucial to endurance athletes, including immune function, hormone production, and enzyme activity. For these reasons, maintaining an adequate protein intake is essential for endurance athletes who place high demands on their bodies. Research suggests that athletes in endurance sports consume less protein than athletes involved in strength sports such as bodybuilding or weightlifting (1). Most likley, a historical hangover that protein will bulk you up as an endurance athlete. All of which is utter nonsense. The stimulus of hypertrophic resistance training combined with a surplus of calories, including a higher protein intake, would be required for that to occur. It's unlikely in most endurance/triathlete worlds. Given the sheer volume of training and the repeated stress on muscles and joints, triathletes need sufficient protein to aid in recovery and maintain performance throughout long training blocks and race seasons.
‍

Is a High Protein Diet Harmful?

The recent media buzz surrounding the potential dangers of high protein consumption has confused many athletes (2). Reports often suggest that excessive protein intake can harm the kidneys, liver, and bones, raising concerns that a high-protein diet could be detrimental to long-term health. However, most of these concerns stem from studies on individuals with pre-existing health conditions, such as kidney disease, rather than healthy athletes.
‍

The Science of High Protein Diets ‍

In healthy individuals, no substantial evidence exists that consuming a higher protein intake leads to kidney damage or other adverse health outcomes. The International Society of Sports Nutrition (ISSN) has stated that protein intakes of up to 2.0-2.2 grams per kilogram of body weight per day are safe and potentially beneficial for athletes engaging in intense training (3). Higher protein diets can benefit athletes who aim to enhance recovery, build lean muscle mass, and maintain body composition during periods of high training intensity. This intake level far exceeds the general recommended daily intake (RDI) of protein for the average population, 0.8 grams per kilogram of body weight. This recommendation is set to support life, not to enhance or thrive. Certainly not the amount required for continually stressing your body through training. Training status is irrelevant to this as well. Whether you are a novice or a highly trained professional athlete, your intake of protein will and should be higher than the 0.8g/kg/BW recommendation.
‍

The Impact of Total Protein vs. Timed Protein Intake

While total protein intake is essential, recent research has also highlighted the importance of protein consumption timing. Because we now know that large protein meals can benefit athletes (5), protein distribution also fulfils the practical element of allowing athletes to hit their total protein targets whilst training effectively throughout the day. It is possible to improve muscle protein synthesis (MPS) with a single, large intake of at least 100g of protein. Something that until 2023 was unknown; it is not so easy to go and do a threshold session with that in the gut! For triathletes, spreading protein intake across meals and snacks, emphasising post-workout recovery, for the most part, is about the practical elements of hitting total protein intake for the day whilst still being able to train and go about one’s day job. Spreading out the intake of protein will maximise the benefits of their nutrition plan, including enhancing muscle repair, growth and recovery. (4)  
‍

How Fuelin Optimizes Protein Intake for Athletes

At Fuelin, we optimize protein intake by focusing on the total amount of protein consumed combined with how and when it should be consumed. Our program is designed to tailor nutrition plans to each athlete, ensuring they get enough high-quality protein to support their training and recovery. We use cutting-edge tools like our Scooter AI food tracker, enabling athletes to track their food intake accurately and ensure they hit their protein targets. By analysing food choices in real-time, the Scooter AI food tracker allows athletes to quickly and easily assess and track their protein intake and compare it seamlessly to their recommended needs. Fuelin accounts for training volume, intensity and personal goals.
‍

Recommendations for Increasing Protein Intake

If you're concerned that you're not getting enough protein to support your training, here are a few strategies to increase your intake:

- Eat protein-rich foods at every meal. Lean meats, fish, eggs, dairy products, and plant-based options like tofu and lentils are excellent protein sources.

- Incorporate protein-rich snacks. Greek yogurt, chicken breast, cold cuts, cottage cheese, protein shakes, or nuts can help you hit your protein goals without feeling overly full.

- Consider fortifying protein-containing foods with protein powder (whey or plant). Milk, yoghurt, oats, and cereals can all be enhanced by adding protein powder.

- Prioritise post-workout protein. Consuming 30-40+ grams of protein within 60 minutes of completing your workout can significantly enhance muscle recovery. The total protein requirements of the individual athlete will determine this.

- Use protein supplements if needed. While whole foods should be your primary source of protein, supplements like whey or plant-based protein powders can help athletes meet their needs. Particularly for heavier athletes whose training volume is high and protein requirement is larger.
‍

Groups That Benefit from Higher Protein Intake

The benefits of a higher protein intake extend beyond active athletes to various groups with specific physiological needs, including:

Older Adults (>50 Years):
As we age, our bodies experience a natural decline in muscle mass and function, known as sarcopenia. This process can be mitigated by increased protein intake, which stimulates muscle protein synthesis and helps maintain lean muscle mass and physical performance (6-8). Higher protein intake is especially valuable for older adults, who often experience anabolic resistance, meaning their muscles respond less effectively to protein than younger individuals. By increasing protein consumption, older men and women can support muscle health, functional independence, and overall vitality.

Youth (Male and Female):
Adolescents in sports or physically active lifestyles require adequate protein to support their growth and physical training demands. Protein is critical in developing lean body mass and ensuring recovery from exercise, which is especially important during growth spurts. In particular, active youth can benefit from sufficient protein intake to support their developing bodies, aid in injury prevention, and fuel performance. Further research supports the idea that higher protein intake can benefit endurance athletes. Athletes with a protein-rich diet display improved recovery and less muscle damage than those with lower amounts of protein(1,2). Higher protein intake has also been associated with enhanced immune function and reduced athlete illness risk (1,2).

Menopausal Women:
Menopause brings about significant hormonal changes, including a reduction in estrogen, which affects muscle and bone health. Studies suggest that menopausal women are at increased risk of muscle loss, reduced bone density, and weight gain. Increased protein intake can help combat these effects by promoting muscle retention and supporting metabolic health. In addition, a higher protein diet, combined with resistance training, has improved lean muscle mass and maintains strength, offering essential benefits for long-term health and resilience (6-8). Interstingly, when menopausal women consume a higher protein diet, they tend to reduce their intake of fat and carb-containing foods. This reduction can lead to a reduced overall calorie intake, and thus, the benefits of a higher protein intake may be induced simply by a higher satiation.

Athletes in a Calorie Deficit:
When athletes are in a calorie deficit—aiming to lose weight or striving to maintain a lean body composition—protein becomes a critical component of their diet. When calorie intake is reduced, the body often turns to muscle tissue for energy, which can lead to a loss of lean muscle mass alongside fat loss. A higher protein intake can counteract this effect by promoting muscle protein synthesis, helping to preserve muscle tissue even in a calorie-restricted state. Furthermore, studies have shown that a protein-rich diet increases satiety, helping athletes feel fuller for longer and making it easier to adhere to a reduced-calorie diet without sacrificing muscle (2). For endurance athletes, maintaining lean muscle is crucial to performance, as it aids in power, endurance, and overall metabolic function. Thus, a high-protein diet during periods of caloric restriction can support body composition, athletic performance and recovery.

Injury Rehabilitation:
Injuries are an unfortunate reality for many athletes, and recovery requires a carefully managed approach to nutrition. When the body is healing, it demands additional resources for tissue repair, with protein being a primary building block for regenerating muscle, tendons, and ligaments. Studies have demonstrated that increased protein intake can expedite the healing process by supplying the amino acids necessary for cellular repair and reducing muscle atrophy, a common issue during periods of immobility (9). This need for higher protein is especially relevant when an athlete’s activity is limited due to an injury, as a sufficient intake helps to prevent unnecessary muscle loss and maintain strength. By prioritising protein in their recovery nutrition, athletes can promote more effective healing, support faster tissue regeneration, and return to training stronger and more resilient.

By targeting these groups and optimising their protein intake, Fuelin’s approach can help meet the unique needs of different age groups and physiological stages, from active youth to older adults, menopausal women, athletes in a calorie deficit, and those recovering from injury. This ensures everyone benefits from a balanced, protein-rich diet to support health and performance goals at every life stage.
‍

The Potential Drawbacks of a High-Protein Diet

While higher protein intake is generally safe for athletes, it's essential to maintain a balanced diet. Excessive protein consumption, particularly from supplements or processed sources, can displace other vital nutrients, such as carbohydrates and fats, which are also critical for endurance performance. Moreover, excessive reliance on protein shakes or processed protein foods may lead to nutrient deficiencies, as whole foods provide a wide range of vitamins, minerals, and fibre that supplements often need more.
‍

Conclusion: Is Too Much Protein Bad for You?

In conclusion, while media reports may cause some to question the safety of higher protein intake, the evidence strongly supports protein benefits for endurance athletes, especially triathletes. With no substantial risks for healthy individuals, a moderate to high protein intake can improve recovery, muscle maintenance, and overall performance. At Fuelin, we help athletes optimise their protein intake, ensuring they get the proper amounts at the correct times. With tools like Scooter, our AI food tracker, we make it easier for you to stay on track and perform your best.

Are you ready to level up your nutrition and performance?
‍

References

1. Phillips, Stuart M, and Luc J C Van Loon. “Dietary protein for athletes: from requirements to optimum adaptation.” Journal of sports sciences vol. 29 Suppl 1 (2011): S29-38. doi:10.1080/02640414.2011.619204
2. Alberto et al. “High Protein Diets and Glomerular Hyperfiltration in Athletes and Bodybuilders: Is Chronic Kidney Disease the Real Finish Line?.” Sports medicine (Auckland, N.Z.) vol. 54,10 (2024): 2481-2495. doi:10.1007/s40279-024-02086-1
3. Jäger, Ralf et al. “International Society of Sports Nutrition Position Stand: protein and exercise.” Journal of the International Society of Sports Nutrition vol. 14 20. 20 Jun. 2017, doi:10.1186/s12970-017-0177-8
4. Areta, José L et al. “Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis.” The Journal of physiology vol. 591,9 (2013): 2319-31. doi:10.1113/jphysiol.2012.244897
5. Trommelen, Jorn et al. “The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans.” Cell reports. Medicine vol. 4,12 (2023): 101324. doi:10.1016/j.xcrm.2023.101324
6. Moore et al. “Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men.” The journals of gerontology. Series A, Biological sciences and medical sciences vol. 70,1 (2015): 57-62. doi:10.1093/gerona/glu103
7. Silva TR, Oppermann K, Reis FM, Spritzer PM. Nutrition in Menopausal Women: A Narrative Review. Nutrients. 2021 Jun 23;13(7):2149.
8. Greendale et al. “Changes in body composition and weight during the menopause transition.” JCI insight vol. 4,5 e124865. 7 Mar. 2019.
9. Tipton et al. “Assessing the Role of Muscle Protein Breakdown in Response to Nutrition and Exercise in Humans.” Sports medicine (Auckland, N.Z.) vol. 48,Suppl 1 (2018): 53-64. doi:10.1007/s40279-017-0845-5

‍