Keto Diet: Understanding Carb Limits And Flexibility

The ketogenic, or keto, diet is a low-carb, high-fat eating plan that has been used for centuries to treat specific medical conditions. The diet restricts total carbohydrate intake to less than 50 grams a day, with the goal of achieving a metabolic state called ketosis. Ketosis occurs when the body is deprived of glucose, its main source of energy, and begins to burn fat for fuel instead. While in ketosis, the body also produces less insulin and stores less fat. To achieve and maintain ketosis, most people will need to consume less than 50 grams of net carbs per day. Net carbs are calculated by subtracting dietary fiber and sugar alcohols from the total number of carbohydrates.

Net carbs vs total carbs

Net carbs refer to the total amount of digestible carbohydrates in a food product or meal. They are calculated by subtracting the amount of fibre and some sugar alcohols from the total amount of carbohydrates. Net carbs are an important consideration for people following a keto diet because only net carbs are counted when calculating daily consumption.

Total carbs include all types of carbohydrates, including fibre and sugar alcohols, which are not fully absorbed by the body. The keto diet is a low-carb, high-fat diet that involves taking an extremely low amount of carbohydrates and substituting them with fat to stimulate the body's fat-burning processes. The body enters a state of ketosis, where it changes from using glucose as its primary energy source to using ketones created from fat metabolism.

The key difference between net carbs and total carbs is that net carbs only include carbs that the body can fully digest into glucose. Total carbs, on the other hand, include all the different types of carbs in a food or meal, such as starches, dietary fibre, and sugars. Net carbs are determined by removing fibre and sugar alcohols from the total carbohydrates count.

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 is important to note that food nutritional labels can vary and may cause confusion, and that methods for calculating net carbs are only estimations as everyone's digestive system is different.

While the keto diet focuses on net carbs, most dietitians advise focusing on total carbohydrate consumption as the accurate measurement for weight loss. This involves consuming low-carb whole meals such as non-starchy vegetables, fruits with high fibre content, leafy greens, healthy fats such as olive oil, and high-quality meats and fish.

How to calculate net carbs

To calculate net carbs, you need to subtract the amount of fibre and, in some cases, sugar alcohols from the total number of carbohydrates. This is because fibre and some sugar alcohols are not digestible, so they don't count towards your net carb intake.

Net carbs are sometimes referred to as digestible or impact carbs. They are the carbs that are absorbed by your body and include both simple and complex carbs. Simple carbs are found in things like fruits, vegetables, milk, sugar, honey and syrup, while complex carbs are found in grains and starchy vegetables like potatoes.

When calculating net carbs, you can subtract the total amount of dietary fibre from the total carbs per serving. For example, if a food contains 20 grams of total carbs and 10 grams of dietary fibre, it has 10 grams of net carbs.

Sugar alcohols are used to add sweetness to many low-carb foods. Your body processes them similarly to fibre, but not all sugar alcohols are created equal. Erythritol, for instance, has a very low glycemic index and isn't fully digested by your body, so you can subtract its total value from the total carbs. Other sugar alcohols, like maltitol, sorbitol and glycerin, do affect your blood sugar and are partially digested, so you should only subtract half of their total value from the total carbs.

Calculating net carbs can be especially useful for people with diabetes, as it can help them track their intake of dietary fibre and balance their medications with their carb intake. 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.

What foods are low in net carbs?

The keto diet is a low-carb, fat-rich eating plan that has been used to treat specific medical conditions. To stay in ketosis, a person can consume up to 50 grams of carbs per day. The keto diet involves moderate amounts of protein, as excess protein can prevent ketosis.

Animal Proteins

Animal protein has close to zero carbs. Organ meats, such as raw beef liver, are an exception. Examples include:

• Pork, including bacon
• Fish and other seafood, which are particularly high in B12, iodine, and omega-3 fatty acids

Vegetables

Most vegetables are low in carbs. Leafy greens and cruciferous vegetables have very low levels, and most of their carbs consist of fiber. Starchy root vegetables like potatoes and sweet potatoes are high in carbs and should be avoided. Examples of low-carb vegetables include:

• Broccoli
• Eggplant
• Asparagus
• Peppers
• Cauliflower
• Brussels sprouts
• Collard greens

Fruits

Most fruits are high in carbs compared to vegetables. Depending on your desired carb intake, you may want to restrict your fruit intake to 1-2 pieces per day. However, avocados, olives, and low-sugar berries, such as strawberries, are good low-carb options.

Nuts and Seeds

Nuts and seeds are popular on low-carb diets. Some are high in fat, fiber, protein, and various micronutrients. 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 yogurt
• Cheese, such as cheddar or 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
• Coconut oil

Beverages

Water, coffee, tea, and sugar-free carbonated water are the safest beverages to drink on a low-carb diet. Fruit juices are very high in sugar and carbs and should be avoided.

Other Foods

Some other low-carb foods that don't fit into the above categories include:

• Dark chocolate (at least 70-85% cocoa content)
• Herbs and spices
• Unsweetened coconut

What are the health benefits?

The keto diet has been used for centuries to treat specific medical conditions. In the 19th century, it was used to control diabetes, and in 1920, it was introduced as an effective treatment for epilepsy in children. The diet has also been tested and used in closely monitored settings for cancer, diabetes, polycystic ovary syndrome, and Alzheimer's disease.

The keto diet has several health benefits, including:

• Weight loss: The keto diet has been shown to promote weight loss, even without counting calories. This is because the body burns fat instead of carbohydrates for energy, leading to a reduction in fat storage.
• Improved blood sugar control: The keto diet can help decrease blood sugar levels, making it beneficial for people with type 2 diabetes.
• Lower blood pressure: The keto diet has been found to reduce blood pressure, which is beneficial for cardiovascular health.
• Improved cholesterol levels: Following a keto diet can lead to an increase in HDL (good) cholesterol and a decrease in triglycerides, which are associated with improved heart health.
• Appetite suppression: The high-fat content of the keto diet leads to a satiating effect and decreased food cravings. This can help reduce overall calorie intake and promote weight loss.
• Increased calorie expenditure: The metabolic effects of converting fat and protein to glucose on the keto diet can lead to increased calorie expenditure, further contributing to weight loss.
• Promotion of fat loss: The keto diet promotes the loss of fat mass instead of lean body mass, partly due to decreased insulin levels.
• Nutritional benefits: The keto diet includes a variety of nutritious, whole foods such as non-starchy vegetables, healthy fats, and high-fiber, low-fructose fruits.
• Management of insulin sensitivity: The keto diet can help manage insulin sensitivity and diabetes by reducing insulin levels and improving insulin resistance.
• Reduced bloating: The low-carb nature of the keto diet leads to a reduction in water retention and bloating.

While the keto diet has many potential health benefits, it is not suitable for everyone. It is important to consult with a healthcare professional before starting any new diet, especially if you have a chronic health condition. Additionally, the keto diet can be challenging to maintain due to its restrictive nature and potential side effects such as hunger, fatigue, low mood, irritability, and constipation.

How to achieve ketosis

Ketosis is a metabolic state where the body burns fat for fuel instead of carbohydrates. This happens when the body is deprived of glucose, its main source of energy, and starts producing ketones, an alternative fuel source. Ketosis can be achieved through a ketogenic (keto) diet, which is a low-carbohydrate, high-fat eating plan. Here are some steps to help you achieve ketosis:

Pick Your Keto Diet

There are several variations of the keto diet, including:

• The Standard Ketogenic Diet (SKD): This is the most common form of the keto diet, which involves a very low-carb, moderate-protein, and high-fat intake. The recommended ratio is 70-75% fat, 15-20% protein, and 5-10% carbohydrates.
• The Cyclical Ketogenic Diet (CKD): This version allows for two non-consecutive days of higher-carb intake, usually for athletic performance. The total carbohydrate intake can vary between 100-150g on those days.
• The Targeted Ketogenic Diet (TKD): Similar to CKD, but higher carbohydrate foods are consumed before workouts instead of planning entire days of higher carb intake.
• The High-Protein Ketogenic Diet (HPKD): This diet involves 30% protein, 60-65% fat, and 5-10% carbohydrates. It is easier to implement but harder to get into and maintain ketosis.
• Dirty Keto/Lazy Keto: This simplified version of the keto diet keeps the daily carb limit below 5-10% of total calories, without specifying the exact ratio of fat and protein.

Calculate Your Macros

Macros refer to macronutrients, which are the foods that give your body energy. The three forms of macronutrients are carbohydrates, proteins, and fats. To achieve ketosis, you need to calculate your daily caloric needs and determine the right ratio of these macros. Here's an example calculation for a 1500-calorie SKD:

• Calories from carbs: 1500 calories x 10% = 150 calories, which is 38 grams of carbs.
• Calories from protein: 1500 calories x 20% = 300 calories, which is 38 grams of protein.
• Calories from fat: 1500 calories x 70% = 1050 calories, which is 117 grams of fat.

Test for Ketosis

There are several ways to test if you have achieved ketosis, including blood tests, breathalyzers, and urine tests. One of the first signs that you're on the right track is experiencing the "keto flu," which includes symptoms like headache, fatigue, brain fog, and irritability. These symptoms usually subside within a week or two, after which you'll start feeling the positive effects of ketosis, such as increased energy and reduced appetite.

Foods to Eat and Avoid

To achieve and maintain ketosis, it's important to choose foods with high levels of healthy fats and very low levels of carbohydrates. Here are some guidelines:

• Include: Meat, such as beef, veal, lamb, pork, chicken, and turkey; fish like cod, sardines, tuna, and salmon; most green and leafy vegetables; high-fat dairy like butter and cheese; nuts; seeds; avocados; olive oil; and coconut oil.
• Avoid: Starchy vegetables like potatoes, corn, and winter squash; fruits, especially bananas; grains and grain products like bread, rice, pasta, and cereals; legumes; and sugar and processed foods.

Frequently asked questions