What Does Dr. Stacy Sims Eat Before Workout?

January 3, 2026 •

4 min read

According to Dr. Stacy Sims, a leading female exercise physiologist and nutrition scientist, women should avoid training in a fasted state to minimize cortisol spikes and enhance performance. This approach forms the foundation for her pre-workout nutrition recommendations, which differ based on the type and intensity of the exercise planned.

Quick Summary

Dr. Sims recommends fueling before exercise to avoid high cortisol levels, suggesting specific protein and carbohydrate targets based on workout type. Strength training requires about 15g of protein, while cardio requires both protein and carbohydrates. Examples include protein coffee, Greek yogurt, or a banana with nut butter.

Key Points

Avoid Fasted Training: Dr. Sims strongly recommends against fasted workouts for women to prevent increased cortisol and negative hormonal impacts.
Strength Training Fuel: For lifting weights, eat about 15 grams of protein before to initiate muscle protein synthesis and repair.
Cardio Fuel: For cardio workouts under an hour, consume 15-20 grams of protein plus 30 grams of carbohydrates for energy and stabilized blood sugar.
Listen to Your Body: While general guidelines exist, individual needs vary. Pay attention to how your body responds and adjust accordingly.
Timing is Key: Consume small, easily digestible snacks 30-60 minutes before a workout, or a more substantial meal 90-120 minutes prior to longer sessions.
Sample Snack Ideas: Greek yogurt with berries, a protein shake, a banana with nut butter, or oatmeal with protein powder are effective pre-workout options.

Why Fasted Workouts Hurt Performance for Women

For years, fitness culture has glorified fasted morning workouts. However, Dr. Stacy Sims and her research highlight why this strategy is particularly detrimental for women. For women, morning cortisol levels are already high. Engaging in a fasted workout increases this stress hormone further, which can negatively impact hormonal balance, metabolism, and recovery. Proper pre-workout fueling, even a small snack, signals to the body that energy is available, which helps stabilize blood sugar and reduces the stress response.

The 'Fuel Over Fast' Philosophy

Dr. Sims' core philosophy for women's nutrition is "fuel over fast." This doesn't mean eating a heavy, hard-to-digest meal right before a workout. Rather, it means having a smaller, strategically timed snack to top off energy stores and prepare the body for the coming stress of exercise. This practice supports muscle protein synthesis and overall performance, preventing the negative side effects of fasted training like increased fatigue and metabolic slowdown.

Dr. Sims' Pre-Workout Nutrition Recommendations

Dr. Sims tailors her pre-workout advice based on the specific type of exercise, ensuring the body has the right fuel for the right activity. Here are her guidelines for different workout styles:

For Strength Training

For a weightlifting or resistance training session, the focus is on providing the necessary building blocks for muscle repair. The primary recommendation is a moderate dose of protein.

Target: Approximately 15 grams of protein.
Rationale: This amount initiates muscle protein synthesis, helping to repair and build muscle tissue from the start of the workout.
Example Snacks:
- A small protein shake or half a scoop of protein powder mixed with liquid.
- Greek yogurt with a few berries.
- A couple of hard-boiled eggs.

For Cardiovascular Workouts (up to 60 minutes)

When it comes to cardio, the body relies on carbohydrates for readily available energy. This is where a strategic combination of carbs and protein comes into play.

Target: Around 15 grams of protein and 30 grams of carbohydrates.
Rationale: The carbs raise blood sugar and replenish glycogen stores, while the protein helps maintain stability and supports the nervous system.
Example Snacks:
- A protein coffee: whey protein with sweetened almond milk and espresso.
- Half a banana with two tablespoons of almond or peanut butter.
- Oatmeal with a scoop of protein powder and fruit.

For Longer Endurance Workouts

For workouts longer than 90 minutes, a more substantial meal is required 90-120 minutes beforehand to properly top off glycogen stores.

Target: A balanced meal with complex carbohydrates and protein.
Rationale: Slower-digesting carbs provide sustained energy, crucial for long-duration exercise.
Example Meals:
- Oatmeal with banana, honey, and chia seeds.
- Two slices of toast with avocado and two hard-boiled eggs.

Comparison of Pre-Workout Fueling Strategies


Feature	Fasted Training	Dr. Sims' Fueling Approach (Cardio)	Dr. Sims' Fueling Approach (Strength)
Hormonal Impact	Increases cortisol, which is already high in the morning.	Stabilizes blood sugar and reduces the stress response.	Stabilizes blood sugar and aids in muscle protein synthesis.
Energy Source	Relying on depleted overnight glycogen and stress hormones.	Readily available carbohydrates for immediate energy and protein for muscle support.	Direct protein source to kickstart muscle repair and growth.
Recommended Intake	0 calories	15g protein + 30g carbs	15g protein
Potential Pitfalls	Increased fatigue, impaired performance, metabolic slowdown, potential weight gain.	Potential for minor GI issues if food is not easily digestible.	Needs to be timed correctly to avoid sluggishness.
Primary Benefit	Minimal	Enhanced endurance, stabilized blood sugar, better recovery.	Supports muscle repair, improved strength gains.

The Ideal Timing for Pre-Workout Fueling

Timing is crucial for effective pre-workout fueling. For small, easily digestible snacks, consuming them within 30-60 minutes of the workout is optimal. This provides enough time for digestion without causing a heavy, full feeling. For more substantial meals before longer workouts, aim for 90-120 minutes to allow for more complete digestion. For morning workouts, this means prioritizing a light snack before you head out, rather than waiting until after.

Conclusion: Fueling is a Female Performance Advantage

Dr. Stacy Sims' research confirms that women cannot follow a "one-size-fits-all" nutrition plan developed for men. By avoiding fasted workouts and strategically fueling with appropriate protein and carbohydrates, women can optimize their performance, improve recovery, and better manage hormonal responses to exercise. The specific pre-workout meal or snack depends on the workout's intensity and duration, but the overall message is clear: feeding your body is key to achieving your fitness goals. Embrace the "fuel over fast" mantra and see the difference it makes in your workouts.

For more in-depth information and specific recipes, Dr. Stacy Sims' website is an excellent resource.

Frequently Asked Questions

Dr. Sims advises against fasted workouts because they significantly increase the stress hormone cortisol, which is already naturally high in the morning for women. This can negatively affect hormonal balance, slow metabolism, and impair performance and recovery.

A good pre-workout snack for a morning strength session is something with about 15 grams of protein. Examples include a small protein shake, Greek yogurt, or a couple of hard-boiled eggs.

Before a cardio workout of up to 60 minutes, Dr. Sims recommends consuming a snack with about 15-20 grams of protein and 30 grams of carbohydrates. For longer endurance events, a more substantial meal with complex carbs is needed 90-120 minutes beforehand.

Yes, a protein-coffee drink is a recommended pre-workout option, especially for morning sessions. It combines a protein source (e.g., whey protein) with caffeine and can provide circulating amino acids and energy without feeling overly full.

For a small, easy-to-digest snack, Dr. Sims suggests eating 30 to 60 minutes before your workout. For a more substantial meal before a longer workout, give yourself 90 to 120 minutes for proper digestion.

It is best to avoid heavy, greasy, and high-fiber foods immediately before a workout, as they can cause stomach discomfort, bloating, and sluggishness. Fasted workouts are also strongly discouraged for women.

Yes, nutritional needs can vary during different phases of the menstrual cycle. For example, during the luteal phase, women may need to slightly increase carbohydrate intake, especially before training, and focus on hydration.