Zach Bitter's Periodized Nutrition Philosophy
Unlike many conventional endurance athletes, Zach Bitter does not follow a perpetually high-carbohydrate diet. His nutrition strategy is best described as a periodized high-fat, low-carb (LCHF) approach, which he adjusts based on his training load. The core principle is training his body to become highly efficient at burning fat for fuel, reserving carbohydrates for specific, high-intensity efforts. This system was developed over time after he experienced issues like inflammation and energy swings on a traditional high-carb diet. Bitter explains that his diet during a low-intensity recovery phase looks drastically different from a high-intensity peak training day. The flexibility of his approach is key to its success, allowing him to adapt his fuel intake based on performance rather than adhering to rigid dogma. He views carbohydrates not as an enemy, but as a strategic tool, much like caffeine, to be used for maximum effect.
The Recovery Day Diet
On days with low training volume, Bitter maintains a strict LCHF intake. Carbs may account for as little as 5% of his diet, with the majority of calories coming from healthy fats and proteins. The focus is on whole, animal-based foods. A typical day might look something like this:
- Morning: Coffee with electrolytes; eggs with bacon and spinach.
- Mid-day: A hearty salad or shredded chicken/ground venison with peppers and butter.
- Evening: Fatty fish like salmon or red meat with non-starchy vegetables.
Strategic Carb Refueling
When training intensity and duration increase, Bitter strategically reintroduces carbohydrates. He refers to carbs as “rocket fuel” for very strenuous sessions. This might mean bumping his carbohydrate intake to 10-15% during base-building phases and up to 15-20% for speed work development. This flexible approach allows him to leverage both fuel systems. He has found that for endurance athletes, a slightly higher carb intake (around 100-150g per day) is often more effective than a very strict keto approach during structured training. The timing of carb intake is also periodized, potentially closer to the workout to fuel the session and aid recovery.
The Benefits of Bitter's Approach
Bitter’s decade-plus adherence to this periodized strategy has offered several key performance advantages:
- Efficient Fat Metabolism: Utilizes fat stores for energy, reducing reliance on limited glycogen. This provides stable, long-lasting energy and minimizes constant fueling needs.
- Stable Energy Levels: Helps eliminate energy swings often associated with high-carb diets.
- Reduced Inflammation: The diet has helped him combat chronic inflammation.
- Improved Recovery: Plenty of protein and fat supports muscle repair.
Training vs. Race Day Fueling
Race day requires a different strategy than training. During an ultramarathon, he consumes exogenous carbohydrates (up to 40 grams per hour) to defend muscle glycogen stores. This allows for maximum output without risking digestive distress. He uses products like chia energy gels and exogenous ketones. His fat adaptation allows him to defend muscle glycogen on a lower carb intake than many other runners.
Sample Daily Menus: Low Carb vs. High Carb Phases
| Low Carb (Recovery Day) | Higher Carb (Speed Work) | |
|---|---|---|
| Morning | Coffee with electrolytes; Eggs, bacon, and spinach | Coffee with supplements; Larger serving of eggs and butter with milk and supplement |
| Mid-Day | Cobb salad with various animal products | Ground beef with avocado, kefir, and mixed berries |
| During/Post Training | Smoothie with coconut milk and berries | SFuels Race+ with honey and sweet potato |
| Evening | Salmon, broccoli, and peppers | Ground beef, sweet potato, avocado, spinach, and nuts |
| Snacks/Dessert | Walnuts, full-fat yogurt, and berries | Apples, yogurt, walnuts, tart cherry powder and supplements |
What Zach Bitter Eats in a Day: A Snapshot
Bitter's diet emphasizes whole, unprocessed foods. His go-to items include:
- Animal Proteins: Fatty cuts of beef, venison, salmon, chicken, and eggs.
- Healthy Fats: Olive oil, coconut oil, butter, avocado, nuts (macadamia, walnuts), and full-fat dairy (yogurt, cheese, heavy cream).
- Vegetables: Leafy greens (spinach, kale), broccoli, peppers, cauliflower, and zucchini.
- Fruits (Limited): Berries and apples are used, especially during higher-carb periods.
- Carb Sources (Strategic): Potatoes, sweet potatoes, and honey are added during intense training blocks or racing.
Conclusion: The Adaptable Approach to Fueling
In summary, what Zach Bitter eats in a day is a personalized, periodized nutritional strategy. His success as an ultrarunner is partly due to his ability to train his metabolism to be flexible, relying predominantly on fat for fuel while strategically incorporating carbohydrates for peak performance. This flexible, performance-driven approach is a testament to listening to one's body and adapting nutrition to meet specific training and racing demands. For those interested in adopting a similar strategy, starting with a fat adaptation phase during lower training volume is key, followed by cautious, performance-based carb reintroduction. You can learn more on his website, Zach Bitter's Website.
