Can You Drink Protein Shakes While Intermittent Fasting?
This post contains affiliate links.
Intermittent fasting has become one of the most popular dietary approaches in recent years, and for good reason — it’s simple, flexible, and incredibly effective for weight management, metabolic health, and overall wellness. But as more people combine fasting with fitness goals, another question comes up constantly:
“Can I drink protein shakes while intermittent fasting?”
You’re definitely not alone if you’ve wondered this. With protein shakes, protein powders, meal replacement shakes, protein waters, and high-protein drinks everywhere — plus the need to hit enough protein each day — people want to know how these fit into a fasting routine.
Here’s the good news:
This post breaks down everything you need to know, in a friendly, super-simple way, so you’ll walk away with complete confidence about how to include protein shakes in your intermittent fasting plan.
What Intermittent Fasting Actually Is (Quick Refresher)
Intermittent fasting (IF) is not a diet. It’s an eating pattern based on alternating between:
Periods of eating (your eating window)
Periods of not eating (your fasting window)
The goal is not to restrict types of food but instead to create time-restricted eating hours that support metabolic benefits.
The most common types of fasting include:
16:8 – 16-hour fast, 8-hour eating window
18:6 – A longer fasting period with a 6-hour feeding window
20:4 – A short eating window, sometimes called the Warrior Diet
OMAD – One Meal A Day
Time-restricted fasting – Eating only during certain hours of the day
5:2 dietary approach – Two low-calorie days per week
People choose intermittent fasting because it supports:
✔ Weight management
✔ Lower calorie intake
✔ Improved insulin sensitivity
✔ Balanced blood sugar levels
✔ Better metabolic health
✔ Lean muscle mass preservation
✔ Gut health benefits
✔ Cellular repair
And because it has become such an effective strategy in recent years, people want to know what supplements are “safe” during the fasting window — especially protein drinks.
Do Protein Shakes Break a Fast? The Clear Answer
Let’s get right to it:
YES — all protein shakes break a fast.
Even a small “protein shake break” interrupts fasting because:
They contain calories
They provide essential amino acids
Protein triggers an insulin response
The digestive process ends the fasted state
This includes:
Protein powder mixed with almond milk or water
Meal replacement shakes
Protein water
High-protein smoothies
Super food shakes
Any shake containing grams of protein
Why?
Because the moment you consume calories, your fasting benefits stop temporarily.
During your fasting window, your body is meant to be in a fasted state, which activates processes like:
Fat burning
Lower insulin levels
Cellular repair
Autophagy
Using fat stores for energy
Protein interrupts all of these — even though protein is healthy!
What You Can Drink During a Fasting Window
These beverages do not break a fast:
Water
Black coffee
Unsweetened tea
Electrolytes with zero calories
Zero-calorie drinks that don’t raise insulin
Anything else — especially anything with calories, protein, or healthy fats — belongs in your eating window.
Protein Shakes Belong in the Eating Window — and They’re Incredibly Helpful There
Even though protein shakes break a fast, they are hugely beneficial during your feeding window.
During your eating window, protein shakes help you:
Reach enough protein
Support lean muscle mass
Build and repair muscle tissue
Improve metabolic health
Maintain steady energy levels
Meet nutritional needs
Stay in a calorie deficit if needed
Support post-workout recovery
Maintain a balanced diet
Fuel your fitness goals
Intermittent fasting shortens the number of hours of the day you eat, meaning many people struggle to get adequate protein intake — which is a key factor in weight management and muscle maintenance.
Protein shakes make it much easier.
How Much Protein Do You Need While Intermittent Fasting? (U.S. Metric)
Protein needs are often misunderstood, especially during fasting. Here is the updated U.S. version using pounds, not kilograms.
General guideline: 0.36–0.55 grams of protein per pound of body weight
(For most people)
Active lifestyle: 0.55–0.75 grams of protein per pound of body weight
(If you work out, strength train, or want to maintain lean muscle mass)
This supports:
Muscle repair
Lean body mass
Metabolic benefits
Healthy weight management
Strong energy levels
Because fasting reduces the number of meals you eat, relying solely on whole foods can make it hard to reach these targets.
Protein shakes fill in the gaps.
Example Protein Needs
If you weigh 150 pounds:
Minimum: 150 × 0.36 = 54 grams/day
Moderately active: 150 × 0.55 = 82 grams/day
Very active: 150 × 0.75 = 112 grams/day
A shake containing 20–30 grams of protein can make meeting these goals much easier.
Best Time to Drink a Protein Shake During Intermittent Fasting
Here is the best way to include protein shakes in your eating plan:
1. At the Start of Your Eating Window
Breaking your fast with a high-quality protein shake is:
Gentle on digestion
Stabilizing for blood sugar levels
Supportive of muscle repair
Helpful for reducing cravings later
This is the best way to introduce calories after a fasting period.
2. As a Post-Workout Recovery Drink
If your workout falls within your eating window, drinking a protein shake afterward is ideal.
Protein is essential for:
Post-workout recovery
Muscle repair
Supporting lean muscle mass
Improving strength and performance
Preventing excessive soreness
Your body is most responsive to protein after exercise.
3. As a Meal Replacement (1 per day)
High-quality meal replacement shakes — especially nutrient-rich ones like Farmasi Nutriplus Meal Replacement Shakes — can replace a meal while still supporting:
Fewer calories
Essential nutrients
Energy levels
Balanced diet
Improved digestion
Sustained fullness
These are extremely helpful when your eating period is short.
4. As a Protein Snack Between Meals
A protein shake acts as a convenient, balanced snack during your feeding window. It helps:
Reach daily protein intake
Reduce overeating
Support weight management
Boost energy
Keep hunger stable
Choosing the Right Protein Shake Matters
Not all shakes are created equal. Many popular protein drinks contain:
Artificial sweeteners
Added sugars
Cheap whey protein
Fillers
Additives
Low-quality protein sources
Gut-damaging ingredients
That’s why choosing a high-quality shake is essential — especially when fasting focuses your nutrition into fewer hours of the day.
Why Farmasi Nutriplus Meal Replacement Shakes Are an Excellent Option
Farmasi Nutriplus Meal Replacement Shakes stand out for intermittent fasting because they offer:
High-quality protein
Essential nutrients
High-quality fats for energy
Balanced macros
Support for muscle maintenance
Gut-friendly ingredients
Great flavors
20–30 grams of protein depending on blend
A complete protein source
A “super food shake” style formula
Support for weight management
This makes them ideal during your eating window — especially at the start or as a meal replacement.
For busy women, moms, teachers, or anyone short on time, Farmasi shakes are a great way to nourish your body without spending hours cooking.
Protein Shakes vs. Whole Foods: Which Is Better?
Whole foods should always remain the foundation of a healthy diet. These include:
Lean proteins
Beans & legumes
Whole grains
Vegetables
Nuts & seeds
Eggs
Greek yogurt
Healthy fats
Peanut butter
But whole foods take time. And with a narrow eating period, people often can't comfortably eat everything they need.
That’s where protein shakes come in. They are:
Quick
Convenient
Easy to digest
A simple way to add essentials
Great for filling nutritional gaps
Whole foods + protein shakes = the best combination.
Common Myths About Protein Shakes & Fasting
Myth: A “small” protein shake doesn’t break a fast
Even 10 calories breaks a fast.
Myth: You don’t need much protein when fasting
You may need more, not less.
Myth: Drinking protein increases fat storage
Protein actually reduces hunger and supports metabolic benefits.
Myth: Protein shakes are only for athletes
Protein supports everyone’s health.
Benefits of Including Protein Shakes in Your Eating Window
Here are the biggest advantages:
✔ Supports muscle maintenance
Fasting burns fat stores, not muscle — if protein intake is high enough.
✔ Helps with weight management
Protein keeps you full and decreases caloric intake naturally.
✔ Supports insulin sensitivity
Stable protein intake helps balance blood sugar levels.
✔ Improves energy levels
Protein prevents the crashes that often happen after high-carb meals.
✔ Enhances overall health
Adequate protein supports hair, skin, organs, and immune function.
✔ Makes intermittent fasting easier
Fewer meals means you need nutrient density — shakes help.
How to Break Your Fast the Best Way
A smart, gentle way to break your fast is:
1. Hydrate
Water
Black coffee
Herbal tea
2. Have a nutrient-rich source of protein
A pure protein shake
Eggs
Greek yogurt
3. Follow with whole foods
Balanced meals with:
Protein
Whole grains
Healthy fats
Vegetables
This supports healthy insulin responses and stable energy.
Who Should Consult a Professional Before Adding Protein Shakes?
While protein shakes are generally safe, some people should speak with a doctor, registered dietitian, or nutrition expert such as Julie Upton:
Pregnant or breastfeeding women
Those with kidney issues
People with medical conditions requiring special diets
Individuals with extremely low protein requirements
For most people, protein shakes are a great option for intermittent fasting.
Final Conclusion: Can You Drink Protein Shakes While Intermittent Fasting?
Yes — but ONLY during your eating window.
Protein shakes, protein powders, and meal replacement shakes all break a fast. But they become incredibly helpful during your eating period.
When used correctly, protein shakes help you:
Support lean muscle mass
Improve metabolic health
Reach daily protein goals
Maintain energy levels
Support weight loss goals
Achieve post-workout recovery
Meet nutritional needs
Eat fewer calories naturally
When you choose a nutrient-dense, high-quality option like Farmasi Nutriplus Meal Replacement Shakes, you give your body exactly what it needs during your eating window — especially when you’re on a time-restricted fasting routine.
Intermittent fasting + smart protein intake = a powerful, effective strategy for wellness.