Keto Pepper Steak Low Carb Beef Stir Fry

When I first switched to a keto lifestyle, I worried I’d have to give up my favorite Asian-inspired dishes. Boy, was I wrong! After some experimentation in my kitchen, I’ve perfected this Keto Pepper Steak that rivals any takeout version—minus the carbs, sugar, and unnecessary additives.

This low-carb beef stir fry has become a weekly staple in my home. With tender strips of beef, crisp bell peppers, and a savory umami-rich sauce, it delivers all the flavor you crave without the carb overload. The best part? It comes together in under 30 minutes, making it perfect for busy weeknights when takeout temptation is strongest.

What Makes This Pepper Steak Keto-Friendly?

Traditional pepper steak often contains sugar, cornstarch for thickening, and is served over rice. My version eliminates these carb sources while enhancing the flavor with keto-approved ingredients:

• No added sugars – We let the natural sweetness of the bell peppers shine
• Xanthan gum instead of cornstarch – Provides the perfect thickness without the carbs
• Cauliflower rice substitute – All the texture without the blood sugar spike
• Higher fat content – Keeps you satisfied and supports ketosis

Ingredients You’ll Need

For the Marinade:

• 1.5 lbs flank steak (or sirloin), thinly sliced against the grain
• 3 tablespoons avocado oil
• 2 tablespoons coconut aminos (lower carb soy sauce alternative)
• 1 tablespoon rice vinegar (unsweetened)
• 1 teaspoon sesame oil
• 2 cloves garlic, minced
• 1 tablespoon fresh ginger, grated
• 1/2 teaspoon black pepper
• 1/2 teaspoon sea salt

For the Stir Fry:

• 2 tablespoons avocado oil
• 1 medium green bell pepper, sliced
• 1 medium red bell pepper, sliced
• 1 medium yellow bell pepper, sliced
• 1/2 medium onion, sliced (about 1/2 cup)
• 3 green onions, chopped (white and green parts separated)
• 2 cloves garlic, minced
• 1 tablespoon fresh ginger, grated

For the Sauce:

• 1/2 cup beef broth (make sure it’s sugar-free)
• 3 tablespoons coconut aminos
• 1 tablespoon toasted sesame oil
• 1 teaspoon fish sauce (adds umami, check for no added sugar)
• 1/2 teaspoon red pepper flakes (adjust to taste)
• 1/4 teaspoon xanthan gum (for thickening)

Nutrition Information Per Serving

*Based on a 2,000 calorie diet
*Makes 4 servings

The Secret to Tender Beef

I’ve learned through many (sometimes tough) trials that the key to perfect stir-fried beef is:

1. Slice against the grain – This shortens the muscle fibers, making each bite tender
2. Thin, even slices – For quick, uniform cooking (partially freezing the beef for 20-30 minutes makes this easier)
3. Hot, fast cooking – Keep that wok or skillet screaming hot
4. Don’t overcrowd the pan – Cook in batches if needed

Step-by-Step Instructions

Prep Work (15 minutes)

1. Slice your beef against the grain into thin strips, about 1/4 inch thick.
2. In a medium bowl, combine all marinade ingredients and add the beef. Mix well to coat each piece and let it marinate for at least 15 minutes (or up to 4 hours in the refrigerator).
3. While the beef marinates, slice all your peppers and onions into similar-sized strips.
4. Mince garlic, grate ginger, and prepare green onions by separating white and green parts.
5. In a small bowl, whisk together all sauce ingredients except the xanthan gum.

Cooking Method (15 minutes)

1. Heat a large wok or skillet over high heat until it’s smoking hot. Add 1 tablespoon of avocado oil.
2. Working in batches to avoid overcrowding, quickly stir-fry the marinated beef until just browned on the outside but still slightly pink inside, about 1-2 minutes per batch. Remove and set aside.
3. In the same pan, add the remaining tablespoon of oil.
4. Add the white parts of green onions, minced garlic, and grated ginger. Stir for 30 seconds until fragrant.
5. Add bell peppers and onions to the pan. Stir-fry for 3-4 minutes until they begin to soften but still maintain some crunch.
6. Return the beef to the pan, along with any accumulated juices.
7. Give your sauce a quick stir and pour it into the pan. Bring to a simmer.
8. Sprinkle the xanthan gum over the mixture and stir immediately to incorporate. The sauce will thicken within 1-2 minutes.
9. Cook for another minute to warm everything through.
10. Remove from heat and sprinkle with green parts of green onions.

Serving Suggestions

This keto pepper steak is delicious served over:

• Cauliflower rice (adds only 2g net carbs per cup)
• Steamed broccoli for extra nutrition
• Shirataki noodles (zero net carbs)
• By itself in a bowl—it’s that good!

I like to garnish with:

• Sesame seeds
• Extra sliced green onions
• A drizzle of chili oil for heat lovers

Make-Ahead and Storage Tips

I’m all about meal prep, and this dish works beautifully for planning ahead:

Meal Prep Options:

• Marinate beef up to 24 hours in advance – Store in an airtight container in the refrigerator
• Slice all vegetables up to 3 days ahead – Keep in separate containers in the fridge
• Pre-mix the sauce – It will keep in the refrigerator for up to 5 days
• Complete meal – After cooking, portion into meal prep containers and refrigerate for up to 4 days

Freezing Instructions:

This dish freezes surprisingly well with a few precautions:

1. Slightly undercook the vegetables so they don’t become mushy when reheated
2. Cool completely before portioning into freezer-safe containers
3. Freeze for up to 3 months
4. Thaw overnight in the refrigerator before reheating

Reheating Tips:

• Stovetop – The best method: a quick stir-fry in a hot pan for 3-4 minutes
• Microwave – In a pinch: 2-3 minutes on medium power, stirring halfway through
• Add freshness – Sprinkle with fresh green onions after reheating

Troubleshooting Common Issues

Tough Beef?

• You might be slicing with the grain instead of against it
• The pan might not be hot enough
• You might be overcooking the beef

Watery Sauce?

• Make sure to pat the beef dry before marinating
• Your vegetables might have too much moisture – try cooking them a bit longer before adding the sauce
• Add a tiny bit more xanthan gum (start with 1/8 teaspoon increments)

Too Salty?

• Some coconut aminos brands are saltier than others – adjust accordingly
• Make sure your beef broth is low-sodium
• Balance with a few drops of rice vinegar

Variations to Keep It Interesting

I love experimenting with different flavors while keeping things keto-friendly. Here are some of my favorite variations:

Spicy Szechuan Style

• Add 1-2 dried Chinese chilies
• Include 1/2 teaspoon of Szechuan peppercorns (crushed)
• Increase red pepper flakes to 1 teaspoon

Garlic Lover’s Version

• Double the garlic (or more—I won’t judge!)
• Add 1 tablespoon of garlic chili paste to the sauce
• Include 1/4 teaspoon of garlic powder in the marinade

Thai-Inspired Twist

• Add 1 tablespoon of Thai fish sauce
• Include 1 tablespoon of chopped fresh Thai basil at the end
• Squeeze fresh lime juice over the finished dish

Mushroom Addition

• Add 8 oz of sliced mushrooms (shiitake or cremini work great)
• Sauté mushrooms after the peppers have cooked for 2 minutes
• Include 1/4 teaspoon of dried thyme for additional earthiness

Why This Recipe Works on Keto

I’ve been following a ketogenic diet for over three years now, and I’ve learned what makes or breaks a keto recipe. This pepper steak hits all the right notes:

1. Macronutrient Balance: With approximately 27g of fat, 29g of protein, and only 5g net carbs per serving, it fits perfectly into most keto macros.
2. Sustained Energy: The combination of protein and healthy fats keeps you satisfied for hours, eliminating the energy crashes associated with carb-heavy meals.
3. Inflammation Fighters: Bell peppers are rich in vitamin C and antioxidants that can help reduce inflammation—a key principle of the keto lifestyle.
4. Blood Sugar Stability: By avoiding sugars and starches, this meal helps maintain stable blood glucose levels.

Ingredient Spotlight: Coconut Aminos

One ingredient that might be new to keto beginners is coconut aminos. Here’s why I prefer it over traditional soy sauce:

• Lower in carbs: Contains approximately 1g of carbs per teaspoon versus 1.5g in traditional soy sauce
• Lower in sodium: About 65-75% less sodium than regular soy sauce
• Soy-free: Great for those with soy allergies or sensitivities
• No wheat: Traditional soy sauce contains wheat, making coconut aminos gluten-free
• Subtle sweetness: Adds depth without needing additional sweeteners

If you can’t find coconut aminos, you can substitute with:

• Tamari (gluten-free soy sauce) + a tiny pinch of monk fruit sweetener
• Low-sodium soy sauce (if you don’t have soy sensitivities)

Q&A Section

Q: Can I use a different cut of beef for this recipe?
A: Absolutely! While flank steak is my preference for its flavor and tenderness when sliced properly, you can also use sirloin, skirt steak, or even ribeye. The key is to slice thinly against the grain. Avoid stew meat or cuts with too much connective tissue as they won’t cook quickly enough for a stir-fry.

Q: Is this recipe suitable for dairy-free keto dieters?
A: Yes! This recipe is naturally dairy-free while still being keto-friendly. The fats come from the beef and healthy oils rather than dairy products.

Q: How can I increase the fat content if needed for my macros?
A: Great question! You can easily add more healthy fats by:

1. Drizzling extra sesame oil over the finished dish
2. Adding avocado slices as a side
3. Including 1-2 tablespoons of grass-fed butter in the sauce
4. Serving with a side of keto-friendly creamy cucumber salad

Q: Can I make this in an Instant Pot or slow cooker instead?
A: While you can adapt this recipe for those appliances, you’ll lose the characteristic texture that makes stir-fry special. The high-heat, quick-cooking method is what gives the meat its sear while keeping the vegetables crisp-tender. If you do use a pressure cooker, I recommend still sautéing the ingredients first, then pressure cooking for just 2-3 minutes.

Q: What can I substitute for xanthan gum if I don’t have any?
A: If you don’t have xanthan gum, you have several keto-friendly options:

1. Use 1 teaspoon of guar gum instead
2. Add 1 tablespoon of cream cheese (this will add a slight creaminess)
3. Reduce the sauce longer until it naturally thickens
4. Use 1/2 teaspoon of ground chia seeds (this will add tiny specks to your sauce)

Q: How do I know if I’m getting enough vegetables on keto with this meal?
A: This recipe provides about 1-2 servings of vegetables per portion from the bell peppers and onions. To increase your vegetable intake, consider serving it over cauliflower rice or with a side of steamed broccoli, zucchini, or a simple side salad with a high-fat dressing.

Final Thoughts

What I love most about this Keto Pepper Steak is how it proves that low-carb eating doesn’t mean sacrificing flavor or your favorite cuisines. In fact, I’ve found that limiting carbs has encouraged me to be more creative and intentional with seasonings and cooking techniques.

This dish satisfies my takeout cravings while keeping me on track with my health goals. It’s become such a favorite that even my non-keto friends request it when they come over for dinner!

Remember that keto cooking is about more than just eliminating carbs—it’s about embracing healthy fats, quality proteins, and nutrient-dense vegetables. This pepper steak embodies that philosophy perfectly.

I hope this recipe becomes a staple in your keto kitchen too. And if you’re just starting your low-carb journey, welcome! Dishes like this make the transition so much easier and more delicious than you might expect.