What is a zero-carb diet, often also referred to as a ketogenic or carnivore diet, and how does it differ from a standard ketogenic diet? Specifically, what specific foods are allowed and disallowed on a strict zero-carb diet, considering things like hidden carbs in certain meats or trace amounts of carbohydrates in dairy products? Are there variations on the diet that allow for extremely low-carb foods, and if so, what are examples of those? Furthermore, what are the purported benefits and potential risks or side effects associated with adhering to such a restrictive diet over both the short and long term, citing any relevant research or anecdotal evidence?

Answer

A zero-carb diet, also known as a carnivore diet or a near-zero carb diet, is a highly restrictive eating plan that eliminates almost all carbohydrates. The goal is to derive energy primarily from fat and protein.

Foods Included:

• Meat: All types of meat are allowed, including beef, pork, lamb, poultry (chicken, turkey, duck), organ meats (liver, kidney, heart), and processed meats (bacon, sausage) provided they don’t contain added sugars or carbohydrates.
• Fish and Seafood: All types of fish and seafood are permitted, such as salmon, tuna, mackerel, sardines, shrimp, crab, lobster, and shellfish.
• Eggs: Chicken eggs, duck eggs, and other types of eggs are included.
• Animal Fats: Lard, tallow, ghee, butter (in some variations, in small amounts), and other animal fats are primary sources of energy.
• Bone Broth: Broth made from animal bones is generally allowed.
• Limited Dairy (in some variations): Some variations of the zero-carb diet may allow for small amounts of hard, aged cheeses or heavy cream due to their low carbohydrate content. However, many strictly avoid all dairy.

Foods Excluded:

• Grains: Wheat, rice, corn, oats, barley, rye, and all products made from these grains (bread, pasta, cereal, crackers, pastries).
• Legumes: Beans, lentils, peas, peanuts, and soy products (tofu, tempeh).
• Fruits: All fruits, including berries, apples, bananas, oranges, and melons.
• Vegetables: All vegetables, including leafy greens, root vegetables (potatoes, carrots, beets), cruciferous vegetables (broccoli, cauliflower, Brussels sprouts), and nightshade vegetables (tomatoes, peppers, eggplants). Some very strict adherents may allow minimal amounts of low-carb vegetables like spinach.
• Sugar and Sweeteners: Table sugar, honey, maple syrup, agave nectar, corn syrup, and artificial sweeteners.
• Processed Foods: Most processed foods are excluded due to their carbohydrate content and added ingredients.
• Nuts and Seeds: Almonds, walnuts, sunflower seeds, chia seeds, flax seeds, and other nuts and seeds.
• Dairy (typically): Milk, yogurt, ice cream, and most cheeses are usually excluded due to their lactose content.
• Alcohol: Most alcoholic beverages are prohibited due to their carbohydrate content.
• Oils (plant-based): Vegetable oils like olive oil, coconut oil, and avocado oil are sometimes avoided as the focus is on animal fats.