According to Merck, protein, fat and carbohydrates comprise the three macronutrients that supply 100 per cent of the energy in the human diet. Carbohydrates break down more quickly than the other two and provide the body energy. Fats digest more slowly than the other two and are converted into hormones important for the body's activities. Protein's amino acids act as the building blocks for cells, making them necessary for growth, maintenance and structural support. The popularity of low-carb diets has given carbohydrates a bad reputation. Many carbohydrate-free foods exist, including all sources of protein and fat, but you can find other options as well.
Most low-carb diets are high in protein, a natural replacement for carbs because it provides the same amount of calories (four per gram). Meat provides zero carbohydrates per serving and includes pork, beef, veal, chicken, turkey and duck among others. It can include high amounts of saturated fats, however, which can lead to heart disease if consumed in overly high quantities.
Seafood contains less saturated fat than other forms of meat, as well as providing high-doses of omega-3 fatty acids. These are important substances for the body and can help lower blood pressure and triglycerides according to WebMD. Options include tuna, crab, salmon, shrimp, perch and haddock.
Other protein sources also provide zero carbohydrates including some dairy sources like eggs and cheese. Be careful when choosing dairy however, because even low-fat milk includes over 12 grams of carbohydrate per cup.
Fat does not contain any carbohydrate but does provide plenty of flavour. Look for healthy vegetable oils like sunflower, soybean, peanut, olive, sesame, safflower and canola. They provide nine calories per gram and some, like olive oil, have anti-inflammatory properties according to the Mayo Clinic.
Many beverages do not contain carbohydrates. Choose water, tap or bottled, as well as club soda. Get caffeine from coffee or tea, which do not have any natural carbohydrates. Diet sodas, especially those that are non-cola and contain no caffeine are also carbohydrate free. Even liquor--including gin, rum, vodka and whiskey--contain zero grams of carbohydrate. Just drink the liquor over ice instead of mixing it with juice.
The brain and red blood cells can only use carbohydrates for energy, so don't cut out all carbohydrates. Choose high fibre options to provide energy and help with digestion. Romaine lettuce and spinach provide just over one gram of carbohydrate per cup. Asparagus and cauliflower have a little over 5 grams each and broccoli has around 6.5 grams per cup.