The ketogenic, or "keto," diet, a low-carbohydrate, high-fat eating plan, has gained popularity as a potential weight-loss strategy. While it has been used for centuries to treat specific medical conditions such as diabetes and epilepsy, its recent surge in attention stems from the low-carb diet craze that began in the 1970s with the Atkins diet. The premise behind the ketogenic diet for weight loss lies in depriving the body of glucose, its main source of energy. When carbohydrate intake is severely restricted, the body turns to an alternative fuel called ketones, produced from stored fat.
Understanding the Ketogenic Diet
The ketogenic diet aims to shift the body's metabolism from using glucose to using ketones. This metabolic state, called ketosis, occurs when carbohydrate intake is drastically reduced, typically to less than 50 grams per day, and replaced with fats. The brain, which demands a steady supply of glucose, adapts to using ketones for fuel in the absence of sufficient glucose.
Macronutrient Ratios in Keto
While there isn't a single "standard" ketogenic diet, most versions emphasize a high fat intake (70-80% of total daily calories), moderate protein (10-20%), and very low carbohydrate intake (5-10%). For a 2000-calorie diet, this translates to approximately 165 grams of fat, 40 grams of carbohydrate, and 75 grams of protein. The protein amount is kept moderate because excessive protein consumption can hinder ketosis.
Foods to Avoid and Include
The ketogenic diet strictly limits carb-rich foods, including starches from refined and whole grains, starchy vegetables like potatoes and corn, fruit juices, beans, legumes, and most fruits. Conversely, it emphasizes foods high in saturated and unsaturated fats, such as fatty cuts of meat, processed meats, lard, butter, nuts, seeds, avocados, plant oils, and oily fish. Some dairy products, like cream and full-fat milk, are restricted due to their high lactose (sugar) content, while others may be allowed in moderation.
Sugar Intake on Keto: Daily Limits and Guidelines
For a ketogenic diet to be effective, daily carbohydrate intake should generally remain below 25-50 grams of net carbs. This restriction applies to all forms of carbohydrates, including sugar. Most people following a strict keto diet should limit sugar consumption to less than 10 grams daily to maintain ketosis while allowing some flexibility in food choices. Even natural sugars from fruits count toward this daily total.
Read also: The Role of Cashews in a Weight Loss Diet
Tracking Sugar Intake
It's beneficial to track sugar intake, especially when starting keto. Many people discover hidden sugars in processed foods like salad dressings, sauces, and even some meat products. Reading nutrition labels becomes essential for staying within the daily sugar allowance. As the body adapts to using ketones for fuel, sweet cravings often diminish, making it easier to adhere to the recommended sugar limits.
Net Carbs vs. Total Carbs
When tracking sugar intake, it's crucial to focus on net carbs, which are the total carbohydrates minus fiber and sugar alcohols. Fiber is a type of carbohydrate that the body cannot digest, and sugar alcohols have a minimal impact on blood sugar levels. By subtracting these from the total carbohydrate count, you get a more accurate representation of the carbohydrates that will affect ketosis.
Types of Sugar and Their Impact on Keto
While the keto diet requires precision with carbohydrate intake, certain types of sugar can be included in small amounts. Understanding which sugars fit into your daily macros is crucial for maintaining ketosis while satisfying cravings.
Natural Sugars
Small amounts of natural sugars from whole foods like low-carbohydrate fruits and vegetables can be incorporated into a keto diet. Berries, avocados, and leafy greens are good choices due to their lower carbohydrate content.
Artificial Sweeteners
Low-carbohydrate sweeteners like stevia, erythritol, and monk fruit extract are commonly used in keto-friendly desserts, drinks, and snacks. These sweeteners do not raise blood sugar levels and are generally considered safe. Sucralose is also generally considered keto-friendly, as it is a zero-calorie artificial sweetener that does not contain any carbohydrates or sugars, which means it does not affect blood sugar or insulin levels. However, some sucralose products may contain bulking agents like dextrose or maltodextrin, which add small amounts of carbs.
Read also: Fat Macros for Keto Diet
Sugar Alcohols
Sugar alcohols like xylitol, sorbitol, and maltitol are often used in low-carb products as a sugar substitute. While they are lower in carbs than regular sugar, they can still impact blood sugar levels and cause digestive issues in some people.
Other Sweeteners
Some sweeteners, like allulose, have recently become more popular in the low-carb and keto communities. Allulose is a low-calorie sweetener that does not raise blood sugar levels and can be used in small amounts.
Considerations When Choosing Sweeteners
When selecting sweeteners for a keto diet, consider both their glycemic impact and personal tolerance. Some people find that even zero-calorie sweeteners can trigger cravings or stall weight loss. Rotating different sweeteners can help prevent developing sensitivities or cravings associated with any single option.
How Much Sugar Will Stop Ketosis?
The amount of sugar that will stop ketosis varies from person to person, depending on factors such as metabolic rate, activity level, and individual carbohydrate tolerance. Consuming more carbohydrates than the body can use for energy can lead to increased blood sugar levels, triggering insulin release. Insulin helps move glucose out of the bloodstream and into cells for energy, but it also signals the body to stop producing ketones and shift back to using glucose as its primary fuel source.
As a general rule, consuming more than 50 grams of net carbs per day is likely to significantly decrease the level of ketones in the blood and potentially stop ketosis, depending on the individual. Some active individuals may maintain ketosis with slightly higher carb intake, while sedentary people might need to stay below 20 grams.
Read also: Guidelines for Carnivore Diet Fat
What to Do If You Consume Too Much Sugar
If you accidentally consume too much sugar and exit ketosis, don't panic. The body can typically return to ketosis within 24-48 hours of restricting carbs again, though this adjustment period may be accompanied by temporary fatigue or cravings.
The Role of Insulin in Blood Glucose Regulation on Keto
Understanding the role of insulin in regulating blood glucose levels is essential for achieving and maintaining optimal health on a keto diet. Insulin, produced by the pancreas, helps transport glucose from the bloodstream into cells for energy and storage. On ketogenic diets, insulin levels decrease due to lower carb intake, potentially improving metabolic health over time. Caution must be taken to avoid low insulin levels from leading to hypoglycemia.
Managing Protein Intake
Consuming too much protein on a ketogenic diet can also increase blood glucose levels and insulin release because excess protein can be converted into glucose through gluconeogenesis. Keeping protein moderate-about 0.6-0.8 grams per pound of lean body mass-is recommended to prevent this conversion.
Supporting Immune Health
Increasing fiber and nutrient-dense sources of healthy fats can support overall immune health and help balance insulin production. Taking an integrative approach towards optimizing nutrition while following a keto diet and staying mindful of glycemic control is vital.
Keto-Friendly Sugar Alternatives
When following a keto diet, it's important to limit sugar intake as much as possible. Fortunately, there are several keto-friendly sugar alternatives that can be used to sweeten foods and beverages without raising blood sugar levels.
Stevia
Stevia is a natural sweetener derived from the Stevia rebaudiana plant. It contains little to no calories or carbs and has been shown to help lower blood sugar levels.
Sucralose
Sucralose is an artificial sweetener that is not metabolized, meaning it passes through the body undigested and doesn't provide calories or carbs. Splenda is a popular sucralose-based sweetener, but it contains maltodextrin and dextrose, which add a small number of calories and carbs.
Erythritol
Erythritol is a type of sugar alcohol that's 80% as sweet as regular sugar with just 5% of the calories. Studies show that the carbs in erythritol don't affect blood sugar the same way as regular sugar.
Xylitol
Xylitol is another type of sugar alcohol that is as sweet as regular sugar. Because the carbs in xylitol don't raise blood sugar or insulin levels the same way as sugar, they don't count towards the total amount of net carbs.
Monk Fruit Sweetener
Monk fruit sweetener is a natural sweetener that's 100-250 times sweeter than sugar but contains no calories or carbs.
Yacon Syrup
Yacon syrup is a sweetener rich in fructooligosaccharides, a type of fiber that your body cannot digest. Human and animal studies suggest that yacon syrup may help lower blood sugar and insulin levels.
Sweeteners to Avoid on Keto
While there are plenty of options for low-carb sweeteners that you can enjoy on a ketogenic diet, there are many others that aren't ideal.
Maltodextrin
This highly processed sweetener is produced from starchy plants like rice, corn, or wheat and contains the same amount of calories and carbs as regular sugar.
Honey
High-quality honey contains antioxidants and nutrients, making it a better choice than refined sugar. However, it's still high in calories and carbs and may not be suitable for a keto diet.
Coconut Sugar
Made from the sap of the coconut palm, coconut sugar is absorbed more slowly than regular sugar. However, it's also high in fructose, which can contribute to impaired blood sugar control.
Maple Syrup
Each serving of maple syrup packs a good amount of micronutrients like manganese and zinc but is also high in sugar and carbs.
Agave Nectar
Agave nectar is about 80% fructose, which can decrease your body's sensitivity to insulin and contribute to metabolic syndrome, making it difficult for your body to regulate blood sugar levels.
Dates
This dried fruit is often used to sweeten desserts naturally. Despite supplying a small amount of fiber, vitamins, and minerals, dates also contain a substantial amount of carbs.