Mid-week crashes, sessions that fall apart on Thursday, and motivation that disappears by the end of the week. Most athletes blame their fitness or their programming. Professional surf Ironman Matt Bevilacqua has a different diagnosis: cumulative carbohydrate deficit building session by session until the body says no. You're not undertrained. You're underfuelled.
You're Not Undertrained. You're Underfuelled.
Thursday comes around, and the session falls apart.
Not because the programming is wrong. Not because fitness isn't there. Because the body has been running a fuel deficit since Monday and has quietly been compensating ever since.
Output drops. Perceived effort climbs. What felt manageable on Tuesday feels impossible by Thursday afternoon. Most athletes read that as a fitness problem and respond by adjusting their training.
It's almost never a fitness problem.
Professional Surf Ironman Matt Bevilacqua trains upward of 30 hours a week. Managing that volume consistently across a full week isn't about being fitter than everyone else. It's about understanding what keeps the week intact.
"Consistency is key there, but also listening to my body a lot more. When I'm feeling fatigued, it's mainly just complete that session, don't get outside of your limits, don't push yourself to the next level."
Mid-Week Crashes Are a Fuelling Problem, Not a Fitness Problem
This is the diagnosis most athletes miss.
A mid-week energy crash feels like fatigue. It feels like the body hitting a wall. And because it happens during training, the natural response is to question the training. Too much volume. Not enough rest. Wrong programme.
But cumulative carbohydrate deficit builds session by session. Each session draws on glycogen stores. If intake doesn't fully replace what was used before the next session starts, the deficit carries forward. By Thursday, it's not one session's worth of deficit. It's four.
The body doesn't fall apart on Thursday. It falls apart on Monday when you underfuel.
Most Athletes Track Training Load. Almost None Track Fuel Load.
Training data is everywhere. Session times, distance covered, heart rate, and power output. Athletes track all of it obsessively.
Fuel load gets almost no attention.
But if you don't know what's going into the body relative to what the training demands, you're guessing at your recovery. And at any meaningful training volume, that guess costs your sessions, weeks and over time, results.
One week of proper macro tracking will show you exactly where your week is falling apart. Not where you think it's falling apart but where it actually is.
Mental and Physical Fatigue Feel Identical Mid-Week
This is the part that catches most athletes out.
By Wednesday or Thursday, mental fatigue and physical fatigue become almost indistinguishable from the inside. The session feels hard. Focus drops. The motivation to push isn't there.
Athletes abandon sessions they could have completed because they can't tell whether the body genuinely needs rest or whether the fuel tank is just running low.
Proper fuelling narrows that gap significantly. When carbohydrate stores are maintained consistently throughout the week, the sessions that feel hard on Thursday are genuinely hard, not just because a deficit started building days earlier.
How the Fuel System Actually Works
Three macronutrients. Three distinct roles. When any one of them runs short mid-week, the body compensates by reducing output.
Carbohydrates fuel intensity. High-output efforts draw primarily on glycogen. Running low on carbohydrates midweek means the body can't sustain the same intensity without switching to less-efficient fuel sources. The session doesn't feel harder because you're fitter than the training demands. It feels harder because the fuel isn't there.
Fat fuels duration. Longer, sustained efforts draw increasingly on fat oxidation. Consistent fat intake supports the body's ability to sustain output across extended efforts without relying entirely on carbohydrate stores.
Protein rebuilds what the work breaks down. At high training volume, protein isn't just a recovery tool used after hard sessions. It's a daily maintenance requirement that prevents the body from breaking down muscle tissue when other fuel sources run short.
When any one of these runs short mid-week, it's not a mental block. It's physiology protecting itself.
The Gap Most Athletes Miss: Protein Distribution
Total daily protein intake gets attention. Protein distribution across the day gets almost none.
Muscle protein synthesis needs consistent stimulus across the day, not one post-workout shake and nothing until dinner. The body can only use so much protein at once for synthesis. Spreading intake across multiple meals and snacks throughout the day keeps the synthesis window consistently open, rather than spiking it once and leaving it dormant for hours.
The practical problem for high-volume athletes is time. At 30 hours of weekly training, food preparation time is limited. Sessions, travel, recovery and life don't leave much room for perfectly timed whole-food meals across the day.
BSc protein is built for exactly this scenario. Fast to prepare, practical to hit daily targets across a full training week, and consistent enough to use every day without complexity getting in the way.
Consistency over complexity. Every time.
Fix the Start of the Week, Not the End
The Thursday crash is a symptom. The cause is Monday.
Fuel for the session you're about to do, not the one you just finished. Carbohydrates before intensity. Protein is distributed consistently across the day. Fat is maintained in line with training volume.
Start the week right, and Thursday takes care of itself.
Your week doesn't fall apart mid-week. It falls apart at the start of the week when fuelling doesn't meet demand. Fix that, and what felt like a fitness ceiling is often just a fuel ceiling that moves the moment intake does.
