Feel sharper training fasted? Or do you hit a wall halfway through?

Fasted training is one of the most debated topics in performance nutrition. Some swear by it for fat loss, others feel like zombies 20 minutes into their session.

So—should you do it?

Let’s break it down.

 

What Is Fasted Training?

Fasted training means exercising without eating beforehand—typically after an overnight fast.

It’s common in early-morning athletes or those chasing fat loss. But while it might feel like you're “burning more fat,” the real story is more complex.

 

The Science: What Happens in Your Body

When you train fasted:

Muscle glycogen is lower (your body’s go-to fuel)

Your body increases fat oxidation (burns more fat during exercise)

But it also increases muscle breakdown, especially if intensity is high

Performance suffers in most high-output activities (HIIT, strength, power work)

So yes—you burn more fat during the session.

But that doesn’t always lead to more fat loss overall. And it can come at the cost of strength, output, and recovery.

 

Who Fasted Training Can Work For

Fasted sessions may work if you’re:

Doing low-intensity steady-state cardio (e.g. walking, Zone 2 cycling)

Time-crunched and can’t stomach food early

Not chasing peak performance, strength, or muscle gain

 

Even then, it’s best to keep sessions short (<60 mins) and follow up with quality fuel.

Who Should Avoid Fasted Training

If you’re:

Training hard or lifting heavy

Doing back-to-back or double days

Trying to build or maintain muscle

Feeling lightheaded, fatigued, or weak in fasted sessions

 

...you’re better off fuelling beforehand.

Even a small carb + protein snack can dramatically improve performance, recovery, and results.

 

What to Eat Before Early Sessions (If You’re Short on Time)

You don’t need a full breakfast. Think compact, digestible, effective.

Quick Fuel Options (15–45 mins before):

Banana + peanut butter

Rice cakes + honey

Protein shake + oats

Energy bar or drink + small fruit

 

Even 100–200 kcal can make a noticeable difference.

 

Bottom Line: Should You Train Fasted?

It depends on your goal.

 

If your priority is:

Fat adaptation or you’re doing low-intensity cardio? → Maybe.

Performance, muscle retention, or intense training? → Probably not.

 

Fasted training isn’t magic. But smart fuelling is.

 

Your Next Step

Still unsure if fasted training fits your goals?

Book a 1:1 Performance Fuel Strategy Call and let’s build your fuelling plan together.