100+ of my clients have tried intermittent fasting. Some got shredded. Some lost muscle. Some felt amazing. Some felt terrible. Here's exactly who should do IF, who shouldn't, and the protocol that actually works for fitness goals.
IF works great for fat loss (if you can stick to it)
IF is mediocre for muscle building (eating window limits protein intake)
IF is amazing for some people (fewer meals = simpler)
IF is terrible for others (hunger, low energy, muscle loss)
Bottom line: IF is a TOOL, not magic. It helps some people eat less. That's it. If it fits your lifestyle, great. If not, skip it.
Intermittent fasting = eating all your food within a specific time window.
Most common protocols:
What you CAN have during fasting: Water, black coffee, tea (zero calories)
What breaks the fast: Anything with calories (food, milk in coffee, protein shake)
YES—but not for the reason you think.
IF doesn't magically burn more fat. It just makes it easier to eat less.
The science: A 2020 study found IF resulted in the same fat loss as regular calorie restriction when total calories were matched.
Translation: IF works because you naturally eat fewer calories when you skip breakfast, not because fasting has special fat-burning powers.
My client data: People who do 16/8 IF lose an average of 1-2 lbs/week—same as people eating 3-5 meals/day with the same calorie deficit.
The advantage: Some people find it EASIER to skip breakfast and eat 2 big meals than to portion-control 5 small meals.
IT'S HARDER—but possible.
The challenge: You need to eat 150-180g protein/day + enough calories for muscle growth... all in a 6-8 hour window. That's a LOT of food fast.
Example: 180g protein in 8 hours = 3 meals with 60g protein each. That's 8 oz chicken per meal. Every meal. Doable, but tough.
Study data: A 2016 study found IF resulted in the same muscle growth as normal eating IF protein was matched—but adherence was much lower (people couldn't hit protein targets).
My recommendation: If your goal is maximum muscle gain, skip IF. Eat 3-5 meals spread throughout the day. It's easier to hit protein targets.
IF is GREAT for you if:
IF is TERRIBLE for you if:
Eating window: 12 PM - 8 PM
Fasting window: 8 PM - 12 PM
Sample day:
Who this works for: People who train mid-morning and aren't hungry at breakfast.
Eating window: 8 AM - 4 PM
Fasting window: 4 PM - 8 AM
Sample day:
Who this works for: Morning trainers who want to stop eating by dinner and avoid nighttime snacking.
For fat loss: Yes, training fasted can work. You'll burn slightly more fat (but it's minimal).
For muscle building: No, training fed is better. You'll have more energy and perform better.
My recommendation:
Cardio: Fasted is fine (even beneficial for fat loss)
Lifting: Either take BCAAs before OR move your eating window to include post-workout
You still need 150-180g protein/day. Don't skip protein just because you're fasting.
"I fasted 16 hours so I can eat whatever I want!" = you'll gain fat. Calories still matter.
If you're new to IF, your energy will tank. Ease into fasted training over 2-3 weeks.
IF is just a tool to control calories. It's not special. If you overeat in your window, you won't lose fat.
If IF makes you feel terrible after 2-3 weeks, STOP. It's not for everyone.
I did 16/8 IF for 18 months. Here's what happened:
Pros:
Cons:
My verdict: IF is great for fat loss phases. I don't use it when trying to build muscle (too hard to eat enough).
Should YOU do intermittent fasting?
Try it if:
Skip it if:
The truth: IF is a tool, not a requirement. If it makes eating fewer calories easier for YOU, use it. If not, skip it.
Results come from consistency, not meal timing.
I'll design a meal plan (IF or traditional) that fits YOUR lifestyle and gets you results in 90 days.
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