Elite coaches don’t just tell you what to eat - they tell you when.

Your performance is hanging by a thread. Skip eating before a session, and you’re giving away at your progress. Hit competition on empty, and you’re leaking seconds and power.

Many people talk about fasting. But what’s it really and how can it help us athletes? Let me break it down.

What Is Fasting - and Why It Matters

Intermittent fasting (IF) is simply eating within a time window, then fasting outside that window. It’s when you eat, not necessarily what. A popular example is Time-Restricted Eating (TRE)—like 16:8, where you fast for 16 hours and eat during an 8-hour window.

So you might eat from 12 p.m. to 8 p.m., and fast from 8 p.m. to noon. That’s TRE.

This matters because the timing of your food impacts your fuel flexibility, metabolism, hormones, and recovery. But not all fasts are equal.

TRE

Studies show TRE can be a game-changer for endurance athletes. Male runners on a 16:8 plan for 4 weeks dropped ~0.8 kg of fat, kept their muscle, and saw zero impact on a 10 K time trial. Cyclists on TRE lost 2% body weight and 1% body fat - with no drop in peak power–to–weight ratio. Plus, markers showed lower inflammation and stable VO₂max.

But here’s the caveat: TRE only works if you don’t fast before hard sessions. Race or train high-intensity on an empty stomach, and performance drops ~3.8% - enough to cost you placement.

Why? TRE gives you metabolic flexibility. It helps burn fat. But that doesn’t build your engine - it only helps you shed weight around it.

TRE Fails in Power

For sprinters, lifters, and explosive athletes, fasting before training is a non-starter. Peak power and sprint times drop fast. Wingate tests fall on Day 2 of fasting - and still haven’t fully rebounded by Day 4.

When Fasting Works - and When It Doesn’t

Picture this scenario: You’re two percent lighter, your power-to-weight ratio has improved—but you’re still hitting the same numbers in the gym and on the bike. That’s TRE done right.

But screw it up and this is where you land: you race empty and bomb. You lift light and lose strength. You fast at the wrong time and cry afterward. That’s the gap between smart and stupid.

What You Do Now

Aerobic athletes (runners, cyclists):

• Use 16:8 TRE during base phases - drop fat, keep muscle, preserve VO₂max.

• Never fast before high-intensity workouts over 60 minutes - performance suffers ~4%.

• Fast overnight before easy zone-2 sessions - boost fat adaptation.

• Always eat 2–4 hours before races or big efforts.

Anaerobic athletes (lifters, sprinters):

• Never fast before training or competition - fuel up or watch power crater.

• If you must skip (e.g., religious reasons), train in the morning after a feeding window.

• Keep workouts lighter when fasted.

Rowers:

• Train fasted only on easy morning outings - technique and steady state only.

• Full fueling 2–4 hours before erg or strength sessions.

Simple.

Your Next Move

• In-season? Fuel every session. No fasting before big days.

• Off-season? Try 16:8 TRE. Track performance daily. If performance dips by >3%, dial it back. Don’t fast more than 24 hours.

• Before intense sessions? Eat a proper meal 2–4 hours out.

• Easy days? Fast overnight, do light sessions, then eat at midday.

IF is a body composition tool, not a performance enhancer.

Hope you got some clarity.

Cheers,

Jonas