How many carbs are in a bowl of French onion soup without bread?

French onion soup is a classic French dish that is made by slowly caramelizing onions in butter and oil, then adding broth and wine to create a rich, flavorful soup. It is usually served with a slice of toasted bread and melted cheese on top. But how many carbs are in just the soup itself, without the bread topping? Let’s take a look.

What Are Carbs?

Carbohydrates, or carbs for short, are one of the three main macronutrients found in food, along with protein and fat. Carbs include sugars, starches, and fiber. Some common sources of carbs are grains, fruits, vegetables, legumes, dairy products, and sweets.

When you eat carbs, your body breaks them down into glucose, which is the main source of energy for your cells. The amount of carbs you need varies based on your age, gender, activity level, and health goals. Most health experts recommend getting 45-65% of your daily calories from carbs.

Tracking Net Carbs

To calculate the amount of digestible carbs in a food, you’ll want to look at the net carbs. Net carbs are calculated by subtracting the grams of fiber from the total grams of carbs. Fiber is a type of carb that your body cannot digest, so it does not provide calories or raise blood sugar. Subtracting the fiber gives you the net digestible carbs that impact your blood sugar and provide energy.

Some key things to know about net carbs:

  • Net carbs = Total carbs – Fiber
  • Focus on net carbs rather than total carbs
  • Fiber does not raise blood sugar or provide calories
  • Net carbs give a more accurate view of a food’s effect on blood sugar

When looking at nutrition labels or carb counts, be sure to pay attention to the net carbs rather than just total carbs. This will give you a better understanding of a food’s true carbohydrate content.

Onion Nutrition Facts

Before determining the carb count of French onion soup, let’s look at the nutrition profile of the main ingredient – onions.

Here are the nutrition facts for a medium raw onion (around 110g):

Nutrient Amount
Calories 44
Carbs 10g
Fiber 1.7g
Sugars 5g
Protein 1g

As you can see, half of the carb content comes from natural sugars, while the other half comes from starch and fiber. A medium onion has a total of 10g of carbs, with 1.7g being fiber. So the net digestible carbs in a medium onion is approximately 8.3g.

Onions are low in fat and high in vitamin C, vitamin B6, folate, and manganese. They contain prebiotic fibers that promote good gut health.

Caramelized Onions

When making French onion soup, the onions are caramelized by cooking them slowly over low heat. This brings out their natural sweetness and transforms the starches into sugars through the Maillard reaction.

Caramelizing onions reduces their water content and concentrates the natural sugars. Most sources estimate that caramelized onions end up with about 15-20g of net carbs per cup, compared to 8g in raw onions.

So caramelizing boosts both the flavor and carbohydrate content through turning starch to sugars. Keep this in mind when calculating the net carbs in French onion soup.

Typical Recipe

An authentic French onion soup recipe calls for just a few main ingredients:

  • Caramelized onions
  • Beef or chicken broth
  • Dry white wine
  • Fresh thyme
  • Bay leaf
  • Salt and pepper
  • Bread and cheese topping

Recipes can vary in exact ingredients and proportions, but the basics remain the same. Let’s analyze a typical recipe to determine the net carb count per serving.

Ingredients for 4 Servings:

  • 3 large onions, sliced (~2 cups per onion)
  • 3 Tbsp butter
  • 1 Tbsp olive oil
  • 2 cups beef broth
  • 1/2 cup dry white wine
  • 2 springs fresh thyme
  • 1 bay leaf


  1. Melt butter with oil over low heat.
  2. Add onions and cook slowly for 30-40 minutes until caramelized.
  3. Add broth, wine, thyme, and bay leaf. Season with salt and pepper.
  4. Simmer soup for 10 minutes.
  5. Discard thyme springs and bay leaf.
  6. Ladle soup into oven-safe bowls.
  7. Top with bread slice and cheese.
  8. Broil until bread and cheese are melted and toasted.

Net Carb Calculation

Now let’s calculate the net digestible carbs per serving:

  • Onions:
    • 6 medium onions = ~6 cups onions when sliced
    • With caramelizing, each cup of onions = ~15g net carbs
    • 6 cups x 15g net carbs per cup = 90g net carbs total
  • Broth:
    • 2 cups broth
    • Broth is very low in carbs (~1g net carbs per cup)
    • 2 cups x 1g net carbs per cup = 2g net carbs total
  • Wine:
    • 1/2 cup wine
    • Dry white wine has around 2.5g net carbs per cup
    • 1/2 cup x 2.5g net carbs = 1.25g net carbs total
  • Herbs and seasonings: Negligible carbs

**Total Net Carbs for Entire Recipe: ~93g**

**Serving Size: ~23g Net Carbs**

For a 4 serving recipe, the total net digestible carbs is approximately 93g. So each 1 cup serving (without bread or cheese) contains about **23g of net carbs**.

This number can vary slightly based on the exact recipe, onion size, and cooking time. But a typical bowl of French onion soup without bread will have around 20-25g net carbs.

Tips for Lower Carb Option

Here are some tips for reducing carbs if you want a lower carb version:

– Use a combination of caramelized onions and leeks – Leeks are lower in carbs than onions

– Skip the wine or use 1/4 cup instead of 1/2 cup

– Use chicken broth instead of beef broth – chicken broth has slightly fewer carbs

– Increase broth to 3 cups to dilute the onion carbs

– Top with grated parmesan cheese instead of bread – this avoids the 15-20g carbs from a bread slice

– Add other low carb vegetables like celery or mushrooms

Making these modifications can likely bring the net carbs down to around 15g per serving.

Should You Eat French Onion Soup on a Low Carb Diet?

French onion soup is quite high in carbs, mainly from the large serving of caramelized onions. If you are following a ketogenic diet or a very strict low carb diet under 50g net carbs per day, French onion soup may be too high in carbs to fit your diet.

However, it can likely be enjoyed in moderation on a more moderate low carb diet of around 100g net carbs or less per day. The high fiber and nutrients from the onions is beneficial, so enjoying real French onion soup occasionally may be worth fitting into your daily carb budget.

Some other options if you want the flavor but not all the carbs:

– Make a low carb onion soup recipe that substitutes leeks for some of the onions

– Make a small side serving rather than a large meal-sized bowl

– Order it and only eat the broth and cheese topping, avoiding the bread and most of the onions

With some adjustments and careful portioning, French onion soup can be worked into some low carb eating plans. But it is generally high in net carbs, so frequent or large servings are not ideal for strict low carb diets. Focus on keeping your overall daily carb intake within your target range.


A typical bowl of French onion soup contains around 20-25g net digestible carbs without the bread or cheese topping. This significant amount of carbs comes mainly from the large quantity of caramelized onions, which become high in natural sugars as they cook down.

If you are following a ketogenic or very low carb diet, French onion soup may too high in carbs to fit your daily limits. However, it can likely be enjoyed occasionally on a more flexible low carb diet of 100g net carbs or less. Making some modifications like using leeks, cutting wine, and increasing broth can lower the carb count somewhat.

At the end of the day, French onion soup is a high carb dish due to its focus on caramelized onions. But with careful portioning or recipe adjustments, it can potentially still be enjoyed in moderation on some low carb eating plans. Just be mindful of your total daily carb target and balance your intake.

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