Hello Runner,
Welcome back to your weekly moment of endurance nutrition!
Happy Weekend!
How was your week?
My week was good.
This time, I focused a lot on my studies and content creation.
I kept up with my workouts, but on Thursday I felt really tired. I don't know if it was the yoga class I took that relaxed me so much afterwards, I just wanted to sleep hahahah. Since not everything is perfect, I added an extra coffee to my routine and kept going strong. But all I could think about was going to sleep, hehehe.
Tomorrow is the Barcelona Marathon, and later I'm going to the runners' fair with a friend. I'll see if I can find any new products there to bring back for you guys.
Last week, I talked about the best diet option (low carb, ketogenic, and adequate carb intake) for runners. Science was pretty clear on which one wins for endurance runners. If you missed it, the short version is this: your muscles run on carbohydrates, and consistently under-fueling them costs you performance, recovery, and, over time, your health.
But does every type of running training require the same fuel?
A 20-minute easy jog and a 90-minute tempo session are completely different metabolic events. Eating as if they're the same is one of the most common (and fixable) mistakes I see runners make.
So today, I'm going to talk about carbohydrate periodization. Let’s see what exactly it is, how to apply it to your own training schedule, examples, and more.
Carbohydrate periodization is the practice of matching your carbohydrate intake to the specific demands of each training session, rather than eating a fixed, one-size-fits-all amount every day.
→ On high-intensity days (intervals, tempo runs, race-pace work), you eat more carbohydrates to fuel performance and recovery.
→ On easier days (recovery runs, low-intensity aerobic sessions), you eat fewer, allowing your body to become more efficient at burning fat for fuel and stimulating certain cellular adaptations.
The goal is simple: fuel your hard sessions to train fast and adapt well, and let your easier sessions teach your body to be more metabolically flexible.
The Golden Rules of Pre-Run Nutrition
Before getting into the goal, these are the key principles that apply to all pre-run meals.
Low in fiber
High-fiber foods slow digestion and can cause GI discomfort mid-run. Before training, choose refined or low-fiber carbs. Save the whole grains and vegetables for recovery meals.
Low in protein & fat
Both protein and fat slow gastric emptying and compete with carbohydrate absorption. Keep pre-run protein modest and fat minimal, especially as you get closer to your run.
Liquid as you get closer
The closer to your session, the more liquid your pre-run fuel should be. Solid food 2-1 hours out is fine. Within 45–30 minutes, a sports drink, banana, orange juice, or gel is far easier to digest.
Easily digestible carbs
Opt for high glycemic index, easily absorbed carbohydrates near training. White rice, banana, white bread with honey or jam, grape/orange juice, these are good options before hard sessions.
Timing matters as much as quantity
A large meal too close to training is worse than a smaller, well-timed snack. The American College of Sports Medicine (ACSM) recommends 1–4 hours before, with larger meals earlier and smaller snacks later.
Test before race day
Never try a new food or timing strategy on race day. Your pre-run nutrition protocol needs to be practiced and personalized during training. What works for others may not work for you
Your Carb Periodization Guide by Training Type
The table below translates the carbohydrate recommendations into practical, runner-friendly guidance.
All carbohydrate amounts are per kilogram of body weight (g/kg BW).
A Note on Body Composition
One of the reasons runners are drawn to low-carb approaches is the hope of losing weight and running faster. And while carbohydrate periodization can support body composition goals when implemented correctly, I want to be direct with you: chronically under-fueling to lose weight while training is not a performance strategy, it's a risk.
The IOC's 2023 RED-S consensus statement is unambiguous: energy deficiency impairs bone health, immune function, hormonal status, cardiovascular health, and yes, performance. The path to a leaner, faster body runs through adequate fueling and smart periodization, not restriction.
If body composition is a goal for you, that's completely valid. Let's approach it through a performance-first lens, where your body gets what it needs to train hard, recover well, and adapt over time.
Product of the Week
This week's Product of the Week is the Adidas Evo SL.
I liked these running shoes so much that I can't wear my other shoes anymore (Hoka and New Balance).
These shoes are lightweight, responsive, and have medium cushioning.
The only downsides are that they're a bit unstable and can slip if the ground is very wet.
I don't like to repeat shoes; otherwise, I'd just buy another pair in a different color. But Adidas nailed it with this model!
Your 7-Day Fueling Experiment
For the next week, look at your training schedule and intentionally match your pre-run meal to each session type, using the table above as your guide. A bigger carb meal before your hard days, something lighter before your easy runs.
1- Write down your training sessions for the week and label each one (tempo, long, interval, or recovery)
2- Plan and prepare a pre-run meal or snack for each session based on the carb and timing guidelines above
3- After each run, write down a quick note. How did your energy feel? Any GI issues? Did you fade or feel strong at the end?
At the end of the week, look back at your notes. You might be surprised how much a small shift in timing and carbohydrate amount changes how your body responds; that's the data only you can collect.
Track of the Week 🎧️
This week's Track of the Week is a remix of an old song, but it's trending on social media. I can already see myself running in the spring listening to this song. Good for zone 5 training.
I’ve chosen Just The Way You Are by Milky, Mall Grab
Any questions or something you would like to share, drop me an email
Wishing you a great weekend and week ahead!
Here’s to health and good runs⚡️
Ana Paula Alonso