Hidden carbs mostly come from things added to food, not the food itself. The usual sources are sauces, condiments and dressings; marinades and glazes; sausages and other processed meats; gravies and soups thickened with flour; sweetened dairy and plant milks; "healthy" snacks; and generous portions of sweeter vegetables such as onions and carrots. The fix is simple: read labels per 100 g, learn the other names for sugar and starch, and make the worst offenders yourself. Here is where to look, and what to do about it.
This is general cooking information, not medical advice. Carb figures are approximate, widely published values and vary by brand and recipe.
First, read the label properly
Know which kind of label you have
In the UK and EU, the "carbohydrate" figure on a label already excludes fibre. In the US and Canada, "total carbohydrate" includes fibre, so you subtract it to get net carbs. Comparing an American and a British product without knowing this gives misleading results.
Per 100 g, not per serving
Serving sizes are set by the manufacturer and are often smaller than what people really use. A sauce that looks harmless "per serving" can look very different per 100 g, and per 100 g is the only fair way to compare two brands.
Sugar and starch go by many names
Look for these on ingredient lists: glucose syrup, glucose-fructose syrup, dextrose, maltodextrin, fructose, invert sugar, honey, agave, rice syrup, molasses, fruit juice concentrate, modified starch, cornflour, rusk and wheat flour. Ingredients are listed by weight, so the closer to the top they appear, the more there is.
Where carbs hide
Sauces, condiments and dressings
Tomato ketchup contains about 4 g of carbohydrate per tablespoon, most of it sugar. Barbecue sauce, sweet chilli, teriyaki, hoisin and many "sticky" glazes are usually sweeter still. Balsamic vinegar carries a few grams per tablespoon, while plain wine or cider vinegar has very little. Low-fat dressings are worth a second look too, because sugar and starch often replace the fat that was taken out. Ordinary full-fat mayonnaise, by contrast, is usually very low in carbohydrate.
Marinades, rubs and spice mixes
Ready-made marinades are often sweetened to help meat caramelise, and packet fajita, taco and curry mixes frequently contain sugar, flour or starch as fillers. A home-made mix of spices, salt and oil does the same job without them.
Sausages and processed meats
Many British-style sausages contain rusk or breadcrumbs. Meatballs and burgers from the shop may include breadcrumbs or starch. Some hams and bacon are cured with sugar or honey, and seafood sticks are made with starch. Check the ingredients, and look for sausages with a high meat content.
Gravy, soups and stock
Traditional gravy is thickened with flour, and gravy granules are largely starch. Ready-made soups are often thickened with flour, potato or rice. Some stock cubes include maltodextrin or sugar, usually in small amounts. Reducing a sauce, or thickening it with cream or puréed vegetables, avoids most of this.
Dairy and plant milks
Milk naturally contains lactose, about 5 g of carbohydrate per 100 ml. That adds up across several milky coffees a day. Fruit and flavoured yoghurts usually contain added sugar. Among plant drinks, oat drinks tend to be higher in carbohydrate than unsweetened almond or soya versions. Cream, butter and most hard cheeses are very low.
Vegetables that add up
Vegetables are nutritious and not the enemy, but some are sweeter than people expect. Onions and carrots each contain about 7 g of net carbs per 100 g, peas about 9 g and sweetcorn more. Used for flavour in a sauce, they are rarely an issue. A large bowl of caramelised onions or a heap of glazed carrots is a different matter if you are following a strict plan.
"Healthy" snacks and drinks
Granola, cereal bars, dried fruit, smoothies and fruit juice can all be high in sugar despite their image. Some "sugar-free" bars use maltitol, a sugar alcohol generally reported to raise blood sugar more than erythritol does. Sweet wines, cider, beer and mixers are also easy to forget.
How to take back control
Making the handful of condiments you use most is the most effective change you can make. It takes a few minutes, keeps in the fridge, and means you know exactly what is in the jar. The Keto & Low-Carb Kitchen has a whole chapter of them. Keto Ketchup, Sugar-Free Barbecue Sauce, Classic Vinaigrette and Rich Flourless Beef Gravy between them cover most weekly cooking.
| Ingredient | Where the carbs come from | Easy fix |
|---|---|---|
| Ketchup and barbecue sauce | Added sugar | Make your own with tomato purée, vinegar and spices |
| Gravy | Flour or granules | Reduce pan juices with stock; finish with butter |
| Shop-bought dressing | Sugar, starch, sweet vinegars | Olive oil, wine vinegar, mustard and salt |
| Sausages and meatballs | Rusk and breadcrumbs | Choose high-meat versions or make patties at home |
| Spice mixes | Sugar and flour fillers | Mix your own from single spices |
| Flavoured yoghurt | Added sugar | Plain Greek yoghurt with a few berries |
Cook's tip: once you find a brand of stock, mayonnaise or sausages with a clean ingredients list, write it down. A short list of trusted products saves reading labels every week.
Common mistakes
- Trusting the front of the pack. "Sugar-free" can still mean starch or maltodextrin, and "no added sugar" can still mean plenty of natural sugar. The ingredients list tells the truth.
- Ignoring small, frequent sources. A splash of milk or a spoon of ketchup seems trivial, but several times a day it adds up.
- Cutting vegetables to save carbs. Swap the heavier sources first. Sauces and snacks nearly always matter more than a few carrots.
- Assuming the recipe is the whole story. A low-carb dish served with a sweet dipping sauce is no longer low-carb.
If you are new to low-carb eating, our beginner's guide to keto cooking and our article on low-carb swaps are good next steps. Please remember that very-low-carb diets are not suitable for everyone, including during pregnancy, for people on certain medications and for anyone with a medical condition. A doctor or registered dietitian can help you decide what is right for you.
Questions people ask
Which condiments are naturally low in carbs?
Full-fat mayonnaise, most mustards (except honey mustard), plain wine and cider vinegars, soy sauce or tamari in normal amounts, hot sauces without added sugar, pesto and olive oil are generally low. Always check the label, as recipes vary between brands.
Is "sugar-free" the same as low-carb?
No. A sugar-free product can still contain starch, flour or maltodextrin, and some use sugar alcohols such as maltitol. Check the total carbohydrate figure and the ingredients list, not the claim on the front.
Do carbs in vegetables count?
Yes, they count towards your total, but most leafy and green vegetables are low in net carbs and rich in fibre. The sweeter ones, such as onions, carrots, peas and sweetcorn, are worth portioning if you follow a strict plan. They are still good food.
Why is there sugar in savoury food at all?
Sugar balances acidity, helps browning and caramelisation, adds bulk and can extend shelf life. That is why it turns up in sauces, cured meats and ready meals, and why making your own is the easiest way to leave it out.