Why ‘Clean Eating’ Isn’t Enough: A Scientific Look at Performance Nutrition

As a bodybuilding coach and nutritionist at Unified Strength Methods, I often work with athletes who are doing everything “right” on paper - chicken, rice, veg on repeat, but are still struggling with energy, body composition, or adherence. The problem? Their nutrition is often too rigid and not scientifically aligned with their physiological demands.

While clean eating is well-intentioned, it often oversimplifies what high-performance bodies actually need. Let’s unpack the science behind why eating “clean” doesn’t always equate to eating smart - especially for strength athletes and physique competitors.

1. “Clean” Doesn’t Mean Sufficient

The concept of “clean eating” typically refers to unprocessed, whole foods. While these foods are nutrient-dense, focusing exclusively on them can lead to inadequate energy intake, particularly for athletes with high training volumes.

A 2021 review in Nutrients emphasized that energy availability (EA)—the amount of dietary energy remaining for physiological function after accounting for exercise—is critical for performance and health (Mountjoy et al., 2018). When EA is too low, athletes may experience hormonal disruption, decreased muscle protein synthesis, and impaired recovery. In other words: a clean plate doesn’t always mean a full tank.

2. Macronutrient Distribution Matters

Athletes need specific ratios of carbohydrates, protein, and fats depending on their goals, training phase, and body composition targets. Over-prioritizing lean protein and vegetables - common in 'clean' eating - can leave an athlete under-fuelled with respect to carbs and fats.

According to the International Society of Sports Nutrition (ISSN), carbohydrate needs for strength athletes typically range from 4–7g/kg/day during heavy training blocks (Kerksick et al., 2017). Carbohydrates are essential for glycogen replenishment, neural function, and muscular endurance - not something to fear or eliminate.

Dietary fats also play a critical role in hormone production, especially testosterone, which is vital for hypertrophy (Volek et al., 1997). Over-restriction of fats in pursuit of a “clean” low-fat diet can impair strength gains and long-term recovery!

3. Adherence is a Cornerstone of Success

The best diet is one an athlete can stick to over time. Numerous studies highlight dietary adherence as the most significant predictor of fat loss and performance improvement - regardless of diet type (Hall & Guo, 2017).

Overly restrictive eating patterns, even if comprised of nutrient-rich foods, are less likely to be maintained long-term. Flexible dieting approaches that emphasize energy balance and macronutrient targets - not food moralization - tend to produce better results in both athletic and general populations (Tinsley et al., 2019).

4. Processed Foods Are Not the Enemy

While ultra-processed foods (UPFs) are often associated with negative health outcomes, not all processing is harmful. In fact, strategically including minimally processed or even moderately processed foods can support performance by improving palatability, energy density, and meal compliance - especially during high-volume bulks or intense prep phases. For example, fortified cereals, whey protein, and rice cakes can be functional, digestible, and highly effective for pre- or post-training nutrition!

5. Food Variety Improves Micronutrient Coverage

Eating the same five foods on repeat, even if “clean,” increases the risk of micronutrient gaps. Dietary variety is vital to support immune health, antioxidant defense, and recovery pathways (Thomas et al., 2016). Flexible approaches to food selection help ensure coverage of key nutrients like zinc, magnesium, selenium, and B-vitamins - all essential for high-performing athletes!

Final Thoughts

Nutrition for athletes isn't about perfection - it’s about precision.

Eating “clean” might look good on social media, but it often fails to deliver on the physiological demands of strength training and body composition changes. Performance nutrition needs to be strategic, data-informed, and personalized to each athlete’s training, goals, and metabolism.

At USM, we help athletes go beyond clean eating. We build evidence-based nutrition systems that are sustainable, measurable, and adaptable - so you can focus on what matters: showing up, training hard, and building something that lasts.

Need help aligning your nutrition with your training? Let’s build a strategy based on science, not fads. Reach out to chat about how we can work together.

References:

• Hall, K. D., & Guo, J. (2017). Obesity energetics: body weight regulation and the effects of diet composition. Gastroenterology, 152(7), 1718–1727.

• Kerksick, C. M., et al. (2017). International Society of Sports Nutrition Position Stand: Nutrient timing. Journal of the International Society of Sports Nutrition, 14(1), 33.

• Mountjoy, M., et al. (2018). IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. British Journal of Sports Medicine, 52(11), 687–697.

• Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501–528.

• Tinsley, G. M., et al. (2019). Time-restricted feeding plus resistance training in active females: a randomized trial. American Journal of Clinical Nutrition, 110(3), 628–640.

• Volek, J. S., et al. (1997). Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. Journal of Applied Physiology, 82(1), 49–54.