How many carbs a day on keto

Keto keeps carbohydrates under 50 grams a day; the strict version takes them below 20. It sounds simple until you pick up a label with "carbohydrate" on one line and "fibre" on another and have no idea which of the two to count.

The figures in the examples come from the Ola Keto food database. If you are just starting, read the guide The keto diet for beginners first.

The limits

There is no official definition, though most sources land somewhere around here:

At 20 grams a day almost everyone goes into ketosis. Closer to 50 it varies from person to person: your own body plays a part, and so does how much you exercise.

How to choose your own limit

The easiest way is to spend the first few weeks at 20 grams. At that level ketosis is all but certain and there is no need to measure ketones. Once you know what you are eating, move up slowly with more vegetables or a few berries and see what the scales do (and how you feel).

If ketosis does not interest you and you simply want to cut down on carbs, a low-carb diet under 130 grams leaves you much more room.

Net or total

On keto we count net carbs, that is, carbs without the fibre, which is not absorbed in the small intestine and does not affect ketosis.

The mistake we see most often is with European labels. There the "Carbohydrate" line does not include fibre, so on a pack that says 4 grams of carbohydrate and 3 grams of fibre the net carbs are 4: subtract the fibre and you are taking it off a second time.

American labels work the other way round. "Total Carbohydrate" includes the fibre and you take it out yourself, so 7 grams in total with 3 of fibre makes 4 net. Polyols such as maltitol are counted in the label's carbohydrate too. If you would rather not do the sums in your head, there is the Net carbs converter.

What 20 grams looks like

A slice of toast or a piece of fruit all but uses them up on its own, whereas with vegetables they last the whole day. The figures from the database:

For comparison: 200 grams of spinach, 200 grams of boiled courgettes, 150 grams of boiled broccoli and a 100-gram tomato add up to about 15 altogether. That is more than half a kilo of vegetables, enough for three meals, and you are still under 20.

Where carbs hide

The grams that get away from you are usually in small things. A little milk in your coffee is fine, but over four coffees a day it adds up. Ready-made sauces and dressings often contain sugar or starch; cured meats and shop-bought burgers, breadcrumbs. In "sugar-free" products, too, another carbohydrate has quite often taken the sugar's place.

A 330 ml beer has around 12 grams. With nuts the trouble is the quantity: you eat from the bag and one handful turns into three.

For the first few weeks it helps a lot to write down what you eat and look the figures up in the database. Before long you know them by heart.

Protein and fat

Protein stays moderate and most of the calories come from fat. The Macro calculator works out how many grams of each suit you.

Frequently asked questions

Do the carbs in vegetables count?

Yes, the net ones. In most vegetables, though, there are so few that they rarely push you over the limit; between a salad and a slice of bread there is not much to think about.

What happens if I go over the limit one day?

You may drop out of ketosis for a bit and the scales may creep up from water. The next day you carry on as normal.