CrossFit · Strength

Get leaner without losing strength on the bar

16:8 fasting built around your training: enough protein in your window, a well-fueled WOD and real definition without giving up your numbers.

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16:8Window with the WOD

1.6 g/kgProtein guideline

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Sound familiar?

I want to get lean, but I'm scared of losing strength

You keep your numbers

I train hard and the belly still won't budge

Visible definition

If I train on a full stomach, I perform terribly

Steady energy in the box

What you will notice

What you get out of it

This is what changes in your day to day when you give your body well-guided hours without food.

You keep your numbers

You keep moving the same weight while you get leaner.

Why:With enough protein and strength training, muscle sticks around.

Visible definition

Abs and shoulders show more as the weeks go by.

Why:Fewer hours eating helps cut fat without cutting training.

Steady energy in the box

You hit the WOD with energy and no heaviness in your stomach.

Why:Eating 2-3 hours before and fasting the rest avoids training on digestion.

Solid recovery

You sleep well and show up fresh for the next training day.

Why:Your window starts at or includes post-workout to refuel muscle.

Protein under control

You know if you hit your daily protein without weighing every gram.

Why:Logging meals with a photo keeps you from falling short in your window.

A schedule that fits the box

Train in the morning or the evening, your window adjusts.

Why:Lining up food and training is what makes the difference.

SCIENCE · PHASE BY PHASE

What happens in your body, hour by hour

The app tells you the moment you enter each phase. No more waiting around to "see if it works."

Refuel

Muscle and glycogen topped up

0-4hRefuel

Muscle and glycogen topped up

Last meal with solid protein and carbs if you train tomorrow.

4-10hLow insulin

Overnight recovery

You sleep. This is where the muscle you worked gets repaired.

10-12hTapping reserves

Good window for skill or easy cardio

Mobility, skill work or Z2 fasted if it sits well with you.

12-14hFat burning

Definition in progress

If there's a hard WOD today, plan to eat 2-3h before.

14-16hLight ketosis

Focus and steady energy

Hunger under control. Water with salt if it's hot or you sweat a lot.

16hWindow open

Protein to grow and recover

Open with 30-40 g of protein. Train inside your window.

Your progress

What to expect, week by week

Week 1

You line up window and training. Performance holds while you adapt.

Weeks 2-3

Normal energy in the box and less heaviness before training.

Month 1

More definition in the mirror and the waist, with your numbers intact.

Month 3

Better body composition and a meal plan you've got dialed in.

What the science saysFasting and CrossFit Without Losing Muscle

Reviewed on 12/10/2026

Combined with strength training, 16:8 lets you cut fat while holding onto muscle and strength, as long as protein and energy intake are high enough. The trials run 8 weeks with small samples and show no loss of performance, though one picked up drops in testosterone. Around 1.6 g/kg/day of protein and training inside or close to your window are sensible guidelines.

In 34 trained men, 8 weeks of 16:8 with weight training cut fat and held lean mass and max strength, but testosterone dropped. [1]
In trained women eating 1.6 g/kg/day of protein, a noon to 8 p.m. window didn't slow muscle or strength gains over 8 weeks. [2]
A meta-analysis of 49 trials (1,863 people) found no extra lean mass gain above ~1.6 g/kg/day of protein. [3]

Frequently asked questions

Can I do CrossFit or strength training fasted?

Skill work, mobility or easy cardio, yes. For intense WODs or PR days, most people perform better eating 2-3 hours beforehand. Ideally your hard sessions land inside your eating window.

Will fasting make me lose muscle?

Not if you hit your daily protein, train strength and don't run an excessive calorie deficit. Studies link well-planned intermittent fasting with holding onto muscle mass while losing fat.

How much protein do I need?

As a reference, 1.6 to 2.2 g per kilo of body weight a day, roughly 0.7 to 1 g per pound, spread over 2-3 meals inside your window. Use photo logging so you don't fall short.

What's the best 16:8 schedule if I train?

If you train midday or in the evening, run a noon to 8 p.m. window with training inside it. If you train early, start your window right after the session.

Do I need supplements?

They're not essential. Protein powder or creatine can make hitting your targets easier, but real food is the base. If you have questions or any medical condition, check with a professional.

Scientific sources (4)