French Onion Soup with Melted Cheese
Classic French onion soup (soupe à l'oignon) delights the senses with slowly caramelised onions, deep beef broth and a layer of melted cheese. It has a low glycemic index (clinically reviewed estimate ≈35) and is a warm, comforting winter choice that is gentle on digestion.
Glycemic index
Glycemic load
Calories
Protein
💡 Smart Nutritional Guidance
Consumption advice
Enjoy the warm soup with a spoon and one small slice of baguette, and avoid soaking large amounts of white bread in the bowl.
Best preparation methods
Caramelise the onions slowly over low heat without adding sugar; their natural sweetness comes out with slow cooking in olive oil and aromatic beef stock.
Important Nutritional Note
Caramelised onion is a rich source of quercetin and inulin, which support the arteries and feed beneficial gut bacteria; people with high blood pressure should watch the saltiness of the broth.
Nutrition facts
| Nutrient | Per 100 g | Per typical portion (300 g) |
|---|---|---|
| Calories | 147 kcal | 441 kcal |
| Protein | 6.5 g | 19.5 g |
| Carbohydrate | 15 g | 45 g |
| Available carbohydrate | 13 g | 39 g |
| Fat | 7 g | 21 g |
| Dietary fibre | 2 g | 6 g |
The typical portion is approximate, for comparison purposes.
Comparison & smarter alternatives
Among the foods in French dishes with a glycemic index (5), it ranks 2 (lowest first).
Smart alternatives from the same family:
Frequently asked questions
Does French onion soup raise blood sugar?
No. Its glycemic index is very low (≈35), and the natural fibre and protein in the broth prevent a rise in blood sugar.
How many calories are in a bowl of French onion soup (300 g)?
A bowl provides about 440 kcal (depending on the Gruyère and bread added), with 19.5 g of protein and around 39 g of net starch.
Is the soup suitable for a keto diet?
Yes, if you leave out the baguette topping and keep to the broth, onions and melted Gruyère.
Reviewed by the WiBo Health medical team · Last reviewed 13 October 2026
Disclaimer: This guidance is for nutritional lifestyle orientation and does not constitute a diagnostic medical device under EU Regulation MDR 2017/745.