A ketogenic diet is a low carbohydrate, moderate protein, and high fat diet to allow ketosis to occur throughout the day. When insulin levels in the body are low, the process of ketosis burns body fat for energy. Some benefits of a ketogenic diet may include weight loss, appetite control, and lowered blood pressure. Always speak with your doctor before changing your diet, to make sure it is right for you.
The Standard Ketogenic Diet, which is the most popular version of the keto diet, recommends 75% fat, 20% protein, and 5% carbohydrates.1
Low carbohydrate intake
Carbohydrate intake should generally be under 50 grams per day to maintain ketosis. If your main reason for following the keto diet is weight loss, the amount of carbohydrates in your diet should be limited to 20–25 grams per day. It would be best to spread out consumption of carbohydrates throughout the day in order to meet nutrient requirements with each meal.2
Dark leafy greens, such as kale and spinach, are low in carbohydrates and sodium, in addition to being high in essential vitamins and minerals. Other options for leafy greens include brussel sprouts, cabbage, iceberg lettuce, and fennel.
Vegetables are low-carb and have numerous benefits, such as improving gut health, reducing the risk of metabolic diseases like heart disease, and aiding weight management. Aim to eat vegetables at every meal.
Vegetables that are high in fiber, such as cauliflower, digest slowly so can help you to feel full for longer.
Although aromatics like onions and leeks add flavour, they contain natural sugars so be aware of portion sizes. Limit starchy root vegetables, such as any form of potato, parsnips, and beetroot.
Some examples of the amount of carbohydrates in certain vegetables are:
- 1 bell pepper contains 4 grams of carbohydrates
- A cup of broccoli contains 6 grams of carbohydrates
- A medium cucumber contains 7.3 grams of carbohydrates
- A cup of mushrooms contains 8.3 grams of carbohydrates
Sweetener and sugar intake needs to be limited on a ketogenic diet. Fresh fruits are a great alternative and help regulate blood sugar levels. Berries are high in fiber and rich in antioxidants that reduce inflammation and protect against disease. In addition to strawberries, raspberries, and blackberries, avocados and coconut are the best fruits to include in a ketogenic diet. A study found that people who ate one avocado per day experienced improvements in heart health risk factors, such as reduced levels of LDL cholesterol.3
Some examples of the amount of carbohydrates in certain fruits include:
- 1 avocado contains 17 grams of carbohydrates
- A large peach contains 17 grams of carbohydrates
- A cup of sliced mango contains 24.7 grams of carbohydrates
- A medium apple contains 25 grams of carbohydrates
- A medium banana contains 27 grams of carbohydrates
Moderate Protein Intake
Protein is an essential building block for the body. It helps maintain bone density and strength, in addition to helping repair internal tissues and organs. Protein intake should be approximately 40–50 grams per day for women and 50–60 grams for men on a ketogenic diet. People on ketogenic diets should avoid eating a large amount of protein. This is because it is possible to come out of ketosis and instead undergo gluconeogenesis, which is when the liver converts protein into glucose.
3. Meats and poultry
Meats and poultry are a source of lean protein and can help you feel fuller for longer. Eat a moderate level of meat, including pork, lamb, and poultry.
Skinless chicken breast, ground beef, and lamb contain no carbohydrates. Processed meats like bacon and sausages should be limited, as they are associated with increased risk of cardiovascular disease.
4. Plant-based protein alternatives
Plant-based protein alternatives are a good option for those who do not eat meat. For instance, a cup of tofu contains four grams of carbohydrates and 20 grams of protein.
Eggs are a filling and versatile option as they are low in carbohydrates and a good source of protein, B vitamins, minerals, and antioxidants.
One large egg contains less than 1 gram of carbohydrates and approximately 6 grams of protein.
Fish is a good source of protein, B vitamins, potassium, and selenium. Oily fish, such as mackerel, salmon, tuna, and sardines, are high in essential omega-3 fatty acids, which have been found to lower blood sugar levels and increase insulin sensitivity.
Cheese is high in saturated fat. However, avoid too much cheese and nuts, as they are significantly high in protein.
Plain Greek yogurt and cottage cheese are nutritious, high protein foods, that can be eaten in moderation on a ketogenic diet. They are helpful in reducing appetite and promoting feelings of fullness.
Although dairy products are high in fat, some dairy, such as milk and yoghurt, do contain some carbohydrates in the form of lactose.
High fat intake4
According to the American Heart Association, fats are a vital part of the diet. Fats are essential for the production of fatty acids, as well as being the source of fat-soluble vitamins, such as vitamins A, D, and E.
Although it is possible to have a good amount of fat on a ketogenic diet, it is advisable to choose healthy fats and not to snack in between meals. There are four types of ketogenic-approved fats: saturated, polyunsaturated, monounsaturated, and naturally occurring trans fats. It can be challenging to obtain enough fat without eating too much protein.
8. Healthy oils
Use healthy oils, such as extra virgin, hazelnut, avocado, or coconut.
9. Nuts and seeds
Nuts and seeds are high in fat and low in carbohydrates, as well as being a good source of dietary fiber and magnesium. Choose unsalted nuts as salted nuts can be addictive and lead to overeating.
What should be avoided?
Sweets and high-carbohydrate snacks should be avoided as they contain high levels of trans fats that are associated with weight gain, increased blood sugar, and raised cholesterol levels.
Limit alcohol and avoid juices and sodas; instead, drink water, unsweetened sparkling water, or unsweetened tea and coffee.
Avoid grains, refined sugar, sugar alcohols, and refined vegetable oils. Grains, such as rice, bread, pasta, cereal, and crackers are high in carbohydrates. Sugar, honey, maple syrup, and other forms of sugar are high in carbohydrates and low in nutrients. Avoid margarine as this is a form of processed food.
Always speak to a healthcare professional before starting a new dietary regime. It is important to make sure you are getting enough nutrients while maintaining ketosis. Remember to stay hydrated and avoid sugar and sweeteners. Be aware of side effects, such as dizziness, fatigue, and digestive changes.
1. Dowis K and Banga S. (2021). The potential health benefits of the ketogenic diet: a narrative review. Nutrients. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153354/
2. Batch J, et al. (2020). Advantages and disadvantages of the ketogenic diet: a review article. Cureus. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7480775/
3. Pacheco L, et al. (2022). Avocado consumption and risk of cardiovascular disease in US adults. JAHA. Retrieved from: https://www.ahajournals.org/doi/10.1161/JAHA.121.024014
4. Dietary fats (2021). American Heart Association. Retrieved from: https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/dietary-fats
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