Keto Carb Flexibility: What's Allowed And What's Not

The ketogenic (keto) diet is a high-fat, low-carbohydrate diet that puts the body into a state of ketosis. Ketosis is when the body starts breaking down stored fat into molecules called ketone bodies to use for energy without circulating blood sugar from food. To stay in ketosis, a person can consume up to 50 grams of net carbs per day. Net carbs are calculated by subtracting the amount of fibre and sugar alcohols from the total number of carbs. Net carbs are the ones that are absorbed into your body. While on the keto diet, it is important to consume carbs from whole, unprocessed foods to benefit from their vitamins and minerals.

Net carbs vs total carbs

The keto diet is a low-carb, high-fat diet. It involves taking a very low amount of carbohydrates and substituting them with fat to stimulate the body's fat-burning processes.

Total Carbs

Total carbs include all types of carbohydrates present in food, including fiber and sugar alcohols, which are not fully absorbed by the body. The total carb diet does not restrict carbohydrate intake but emphasizes whole, unprocessed foods, including fruits, vegetables, whole grains, and legumes, while limiting added sugars and refined carbohydrates.

Net Carbs

Net carbs are all the carbohydrates in food that can be absorbed and used by the body for energy. Net carbs are calculated by taking the total number of carbohydrates in a serving of food and subtracting the amount of fiber and sugar alcohols. The body is able to absorb net carbs, also called digestible carbs. Net carbs are the only carbs that count on the keto diet because they are the carbs that raise your blood sugar and kick you out of ketosis.

When following the keto diet, only net carbs are counted when calculating daily consumption. This is because net carbs give a better idea of how many digestible carbs are being consumed and whether the diet is staying within its carbohydrate target. The keto net carb diet limits daily carbohydrate consumption to 20-50 grams to induce ketosis.

Benefits of Net Carbs vs Total Carbs

Switching to tracking net carbs instead of total carbs is less restrictive and allows for more variety in the diet, including avocados, berries, nuts, and low-carb veggies. It also keeps nutrient-dense foods in the diet, whereas total carb keto does not.

Calculating Net Carbs

To calculate net carbs, take the total amount of carbohydrates in a food or meal and subtract the amount of fiber. If the food is processed, also subtract half the sugar alcohol content.

How to calculate net carbs

Net carbs refer to the total amount of digestible carbohydrates in a food product or meal. They are calculated by subtracting indigestible carbs (such as fibre and some sugar alcohols) from the total number of carbs.

To calculate net carbs, you need to know the total number of carbs in a food product or meal, as well as the number of indigestible carbs. This information can be found on food labels, or for whole foods, you can use a database like the USDA Food Composition Database.

To calculate the net carbs in whole foods, you subtract the fibre from the total number of carbs. For example, a medium avocado contains 17.1 grams of total carbs, 13.5 grams of which is fibre. So the net carbs are 17.1 grams of total carbs minus 13.5 grams of fibre, which equals 3.6 grams of net carbs.

To calculate the net carbs in processed foods, you generally subtract half of the carbs from sugar alcohols from the total number of carbs listed on the nutrition label. Erythritol is an exception; if it's the only sugar alcohol listed in the ingredients, its carbs can be completely subtracted from the total carbs.

For example, a maltitol-sweetened Atkins bar label states that it contains 3 grams of net carbs. However, when subtracting only half the carbs from sugar alcohols, the net carb value is 8.5 grams: 23 grams of total carbs minus 9 grams of fibre, minus 11 grams of sugar alcohols (11 grams divided by 2 equals 5.5 grams) equals 8.5 grams of net carbs.

Calculating net carbs can be beneficial for people with diabetes, as it can help them track their intake of dietary fibre and balance medications with carb intake. It can also increase the number of food choices available, as many fruits and vegetables are rich in fibre and contribute fewer carbs to a person's daily goal.

However, it's important to note that the Food and Drug Administration (FDA) does not recognise the term "net carbs" and recommends using the total carbohydrates listed on nutrition labels. Additionally, the method for calculating net carbs is only an estimation, as everyone's digestive system is different.

Foods with low net carbs

To stay in ketosis, a person should consume up to 50 grams of net carbs per day. Net carbs are calculated by subtracting the amount of fibre and sugar alcohols from the total number of carbs. Net carbs are the type of carbohydrates that the body can digest and turn into glucose for energy.

Meat and Fish

Meat and fish are good sources of protein and healthy fats and contain close to zero carbs. Examples include:

• Pork, including bacon
• Fish, such as salmon, sardines, and trout
• Shellfish, such as oysters and mussels

Vegetables

Leafy greens and cruciferous vegetables have low levels of net carbs. Some examples are:

• Broccoli
• Eggplant
• Asparagus
• Peppers
• Cauliflower
• Brussels sprouts
• Turnips

Fruits

Fruits tend to be high in carbs, but some fruits that are lower in net carbs include:

• Avocado
• Apricots
• Raspberries
• Strawberries
• Blackberries

Nuts and Seeds

Nuts and seeds are popular on low-carb diets as they are low in carbs but high in fat, fibre, and protein. Examples include:

• Pumpkin and squash seeds
• Pecans
• Macadamia nuts
• Chia seeds

Dairy

Full-fat dairy products are excellent low-carb foods. Examples include:

• Full-fat yoghurt
• Cheese, such as cheddar cheese and goat cheese

Fats and Oils

Fats and oils do not contain any carbs and are acceptable on a low-carb diet. Examples include:

• Extra virgin olive oil
• Grass-fed butter or ghee
• MCT oil

How to stay in ketosis

Ketosis is a metabolic state in which the body uses stored fat as its main fuel source instead of glucose (sugar). It is characterised by elevated levels of ketones in the blood, which are produced when the liver breaks down fat into molecules that can be used for fuel.

How to Achieve and Stay in Ketosis

Follow a Keto Diet

A keto diet is a way of eating that aims to induce ketosis. Keto dieters consume 60-75% of their daily calories from fat, 15-30% from protein, and only 5-10% from carbohydrates. For the average person, this translates to consuming about 50 grams of carbs or less daily.

Up Your Healthy Fats

On a keto diet, the bulk of your calories comes from fat, which acts as your energy source. If you don’t consume enough fat (60-75% of your daily calories), you’ll likely be tempted to turn to carbs for energy, which would likely kick you out of ketosis.

Plan Meals in Advance

Meal planning is very helpful when it comes to staying in ketosis. Plan out your weekly meals, make a grocery list, and stick to it. This will help you avoid impulsive, high-carb food choices that will boot you out of ketosis.

Keep Keto-Friendly Snacks on Hand

Keep keto-friendly snacks readily available to help you avoid high-carb temptations when hunger strikes. Have snacks like cheese sticks and hard-boiled eggs ready to go in your fridge, and stock up on shelf-stable keto snacks.

Watch Out for Hidden Carbs

Some foods, such as condiments, sauces, salad dressings, and marinades, often contain sneaky carbs (usually refined sugar) that can sabotage ketosis. Read food labels carefully and choose low-carb options to avoid these hidden carbs.

Exercise Regularly

When you exercise, your body is forced to use fat stores as a fuel source, which helps deplete glycogen stores and increase ketone production. In other words, exercise can help you reach and maintain ketosis. Aim for at least 30 minutes of moderate-intensity exercise per day.

Practice Intermittent Fasting

Intermittent fasting (aka time-restricted feeding) involves limiting food intake to a specific time window each day. One of the most widely adopted forms of intermittent fasting is the 16/8 method, which involves eating all of your daily calories within an 8-hour window (and fasting for the other 16 hours).

Stay Hydrated

Adequate hydration is essential for ensuring that ketones can be effectively broken down and utilized for energy. It’s also necessary for the liver to properly metabolize fat, the primary energy source in ketosis. Dehydration can often be mistaken for hunger, leading to overeating carbs.

Non-starchy vegetables

• Broccoli: 3-4 grams of net carbs per serving
• Arugula: 2 grams of net carbs per serving
• Asparagus: 2 grams of net carbs per serving
• Bell Peppers: 3-4 grams of net carbs per serving
• Brussels Sprouts: 3-5 grams of net carbs per serving
• Cauliflower: 3 grams of net carbs per serving
• Kale: 1-3 grams of net carbs per serving
• Mushrooms: 2 grams of net carbs per serving
• Spinach: 1-4 grams of net carbs per serving
• Tomatoes: 3-4 grams of net carbs per serving
• Avocado: 2 grams of net carbs per serving
• Lettuce: 2 grams of net carbs per serving
• Cucumber: 3 grams of net carbs per serving
• Cabbage: 3 grams of net carbs per serving
• Eggplant: 3 grams of net carbs per serving
• Green beans: 4 grams of net carbs per serving

These non-starchy vegetables provide your body with essential nutrients, antioxidants, and fiber while keeping your carb intake low. They can be prepared in various ways, such as steaming, roasting, or stir-frying, and can be paired with healthy fats like olive oil, butter, or cheese.

Frequently asked questions