You can cut out the obvious carbohydrate, the bread, pasta, rice and potatoes, and still find your keto diet quietly not working. The reason is almost always hidden carbohydrate: the sugar and starch that lurk in foods you would not suspect, adding up while you congratulate yourself on skipping the chips. Learning where it hides, and how to read a label, is what separates a keto diet that works from one that mysteriously does not.
Where carbs hide
The usual hiding places are predictable once you know them. Sauces and condiments are the worst offenders: ketchup, barbecue sauce, sweet chilli, many salad dressings, marinades and stir-fry sauces are loaded with sugar. So-called healthy foods are next: flavoured and fruit yoghurts, granola, smoothies, dried fruit and fruit juices are often as sugary as sweets. Processed meats can contain sugar and starchy fillers, so cheap sausages and some deli meats are not the free pass they seem. Drinks are a major route in, from juice and sweetened coffees to certain alcoholic drinks. And “low-fat” versions of foods frequently add sugar to replace the flavour lost with the fat, which is why low-fat can mean higher-carb. None of these announces itself, which is exactly the problem.
Reading the label properly
The nutrition label tells you what you need, if you read it right. Look at total carbohydrate, and look at it per the portion you will actually eat, not per 100 grams or per a tiny “serving” the manufacturer has chosen to flatter the numbers. Check the “of which sugars” line, but remember the total carbohydrate is what matters, since starch counts too even when sugar is low. Then scan the ingredients, because sugar wears many disguises: syrup, glucose, dextrose, maltose, fructose, maltodextrin, honey, concentrated fruit juice and a dozen others are all sugar by another name, and several of them appearing down the list still add up. Ingredients are listed by weight, so sugar near the top means a lot of it.
The net-carb trap on packaged food
Be especially wary of packaged products shouting a low “net carb” number. As the net versus total carbs guide explains, manufacturers of “keto” and “low-carb” products often subtract fibre and sugar alcohols to advertise a tiny net figure, and the subtraction is not always honest, particularly when the sugar alcohol is maltitol, which does raise blood sugar. A bar boasting “3g net carbs” can affect you considerably more than the front of the packet suggests. Treat net-carb claims on processed products as marketing to be checked, not facts to be trusted.
The simplest defence
Here is the move that makes all of this easy: eat mostly whole, single-ingredient foods that do not have a label at all. Meat, fish, eggs, vegetables, nuts and natural fats cannot hide carbohydrate, because there is nothing in them but themselves. The more of your diet comes from foods that never needed a nutrition panel, the less room there is for hidden carbs to creep in, and the less label-reading you have to do. Hidden carbs are overwhelmingly a problem of processed and packaged food, so leaning on whole foods sidesteps most of it entirely.
Eating out
Restaurants hide carbohydrate too, mostly in sauces, glazes, breading and the sugar added to many dishes for flavour. A “savoury” dish can carry a surprising amount of sugar in its sauce, and anything battered, crumbed or glazed is carbier than it looks. The eating-out guide covers this, but the short version is to favour simply cooked dishes, ask about sweet or thickened sauces, and assume that if something tastes sweet or sticky, there is sugar in it.
The bottom line
Hidden carbohydrate, in sauces, “healthy” foods, drinks, processed meats and low-fat products, is the usual reason a careful keto diet stalls. Read labels by checking total carbohydrate per real portion, scanning the ingredients for sugar’s many aliases, and distrusting “net carb” claims on packaged food. Best of all, lean on whole, label-free foods, where carbs cannot hide, and you remove most of the problem without doing any detective work at all.
This is general information about the ketogenic diet, not medical advice. If you are pregnant, on medication, or managing a condition such as diabetes, speak to a doctor or dietitian before changing your diet.