The ketogenic or keto diet is a high fat, moderate protein, and low carbohydrate diet. In the keto diet, many nutrient-rich foods that are sources of carbs, including fruits, vegetables, whole grains, and legumes, are restricted to keep carb intake below 50 grams per day.
The aim of the ketogenic diet is to put the body in a state of "ketosis" by reducing the amount of carbohydrates available to the body. Normally, our body uses glucose from carbs as our primary source of energy. However, in the absence of glucose, the body will turn to using fat instead of carbs as its main energy source. When we do not eat carbs, the liver breaks down fat stores into ketones to produce energy. From an evolutionary standpoint, ketosis is a completely normal, adaptive response by our body to withstand periods of famine. Indeed, the state of ketosis can also be achieved by fasting.
In fact, the ketogenic diet has been used for a long time in the medical field to treat epilepsy in people (especially children) who do not respond to drugs (1). In addition, in recent years, the keto diet has also been used for weight loss (2) and has been shown to improve insulin sensitivity in patients with type 2 diabetes (3). Studies have also shown that a keto diet is more effective for weight loss and blood sugar control in type 2 diabetes than a low calorie diet (4, 5).
There are numerous health benefits from following a keto diet. However, for many people, the keto diet will require making big changes in the foods they eat. The keto diet requires restricting carbs and cutting out otherwise healthy foods, such as whole grains, root vegetables, and fruits, so it is important that you consider the guidelines below to ensure you are following the ketogenic diet in a healthy way.
Guidelines for a Healthy Ketogenic Diet
1.Plan Your Diet Carefully
The Keto diet needs more planning than most other diets. Because of the restrictions and the importance of maintaining a balanced nutritional profile while in ketosis, begin each week with proper meal planning for the week that ensures you will have a balanced diet while following the keto principles.
2.Carb Restriction and Checking for Ketosis
There are several types of ketogenic diets, but the most popular is the “standard” ketogenic diet, in which only 10% of the total daily calories come from carbohydrates. The remaining calories should come from fat (60-70%) and protein (20-30%). For example, if you need to consume 2,000 calories per day, no more than 200 of these calories (or 50 grams) should come from carbs, 400 to 600 calories should come from protein and 1,200 to 1,400 should come from fats.
To check if you have reached a state of ketosis, check your urine for ketones using ketone strips that you can buy either online or in a pharmacy.
3.Foods to Include
- Grass-fed beef
- Fish, seafood, and seaweed
- Bone broth
- Soy (soybeans, tofu, tempeh – but always choose organic soy products as most non-organic soy is genetically modified)
- Oils, such as olive, avocado, and coconut (but avoid processed; use only extra-virgin / cold-pressed oils)
- Nuts, nut butters and nut milks (e.g., almonds, walnuts, hazelnuts, macadamia nuts, pecans, pine nuts)
- High-fat dairy, such as cheese, butter, ghee, cream, and full-fat yogurt
- Seeds (e.g., chia, hemp, sesame, sunflower, flax, pumpkin)
- Low-carb vegetables, such as leafy greens (spinach, kale, arugula, collard greens, lettuce, etc.), zucchini, broccoli, cauliflower, cabbage, peppers, onions, garlic, leek, green beans, peas, cucumber, celery, eggplant
- Fermented vegetables, such as kimchi and sauerkraut
- Some fruits, such as berries, coconut, avocado, limes and lemons, olives, tomatoes.
- Herbs and spices
- Unsweetened tea
- Cacao nibs and 100% dark chocolate
4.Foods to Avoid
- All grain products, such as bread, pasta, rice, baked goods, cereals
- Legumes (except soy products)
- Dairy products (except cheese and butter)
- Root vegetables
- Most fruits (exception: berries)
- Starchy vegetables, such as potatoes
- Processed foods
- Sugary foods and drinks
- Artificial sweeteners
5.Supplements to Consider
- MCT oil to help increase ketone levels
- Psyllium hubs for fiber
- Vitamin D3
6.Keto Diet Tracking App
A tracking app will help you to see whether your meals are meeting the keto diet requirements and whether you are consuming enough nutrients.
7.Sign Up For a Meal Plan
If you are just beginning your keto journey, a specialized professional, such as a nutritionist, will make sure you are following a healthy keto diet, and that you are meeting your nutritional needs and minimizing the risk for complications or negative side effects.
If you prefer not to seek out a professional, there are numerous resources online available to help you plan your keto diet. You may also want to consider a keto-specific meal plan that has been designed to meet your nutritional needs. Meal plans like Green Chef are a great way to start your Keto diet because they have been designed by nutritionists and take much of the guess work out of meeting your nutritional goals.
8.Listen to Your Body
If you are not feeling well (e.g., body aches, headaches, weight gain, weight loss, bloat, tiredness, etc.), make sure you are not missing any food groups or other critical nutrients in your diet. It is critical that you observe how your body is reacting if you are just beginning your transition to a keto diet. To a certain extent, some temporary symptoms can be expected. This is commonly known as the “keto flu” and should pass in a couple weeks. However, if your body continues to react negatively, you should consult a doctor or nutritionist for assistance.
Side Effects of the Ketogenic Diets and How to Minimize Them
If you are just beginning a keto diet, you may experience some temporary symptoms that occur as your body adjusts to a low-carbohydrate diet, such as headaches, dry mouth, bad breath, fatigue, dizzy spells, and nausea. Some people also report trouble sleeping. This is commonly known as the “keto flu”. These side effects usually resolve themselves in about two weeks. To reduce the chances of experiencing these effects, I recommend transitioning slowly onto a ketogenic diet by slowly lowering your carbohydrate intake, while gradually increasing your intake of dietary fat.
Because the keto diet restricts carb intake, dietary fiber intake tends to drop as well, which may have a negative impact on gut health and lead to constipation. Make sure you eat plenty of gut-friendly foods like leafy greens, fermented vegetables, and psyllium husks (see vegetables mentioned above) to keep your gut healthy.
Because the keto diet restricts carbs (fruits and some vegetables), when followed over a long period of time, it can result in vitamin deficiencies if not accounted for correctly. Plan your diet carefully and include as many low-carb vegetables and fruits as possible. You may also want to consider a high-quality vitamin supplement.
4.Cardiovascular Health Markers
The keto diet may cause a substantial rise in low density lipoprotein cholesterol (LDL) levels (6) but the long-term cardiovascular health of people on the ketogenic diet has not been studied yet.
However, high levels of animal fat have been associated with increased cholesterol levels, so give preference to plant-based fats, such as nuts and nut butters, seeds, avocado, and healthy oils (olive oi, avocado oil, coconut oil, etc.), which are rich in beneficial mono- and polyunsaturated fats.
If you have risk factors for heart disease, such as high cholesterol levels, high blood pressure (hypertension), or a strong family history of heart disease, you should be cautious and talk to your physician before starting the keto diet.
Although people seem to lose weight rapidly on a ketogenic diet, some find it difficult to sustain this weight loss long-term. For example, compared to a low glycemic index (GI) diet, people on the keto diet lost more weight (26 vs 23 kg) in the first 6 months, but at the 18 month follow-up, people on the low GI diet had lost more weight than people on the ketogenic diet (7).
The ketogenic diet is a type of low-carb diet that has become popular in the recent years, especially for weight loss. It can be followed in a healthy way by incorporating lots of low-carb vegetables, seeds, nuts, berries, and moderate sources of animal protein. There are some side effects to keep in mind, but also ways to minimize them.
The keto diet is one of the more difficult diets to follow correctly and requires careful planning to achieve the best results. For that reason, if you are just beginning your journey towards ketosis, I would recommend you speak with a nutritionist or consider a keto-specific meal plan to help you design your diet.
- Ulamek-Koziol M, Czuczwar SJ, Januszewski S, Pluta R. Ketogenic Diet and Epilepsy. Nutrients. 2019;11(10).
- Castellana M, Conte E, Cignarelli A, Perrini S, Giustina A, Giovanella L, et al. Efficacy and safety of very low calorie ketogenic diet (VLCKD) in patients with overweight and obesity: A systematic review and meta-analysis. Reviews in endocrine & metabolic disorders. 2020;21(1):5-16.
- Westman EC, Tondt J, Maguire E, Yancy WS, Jr. Implementing a low-carbohydrate, ketogenic diet to manage type 2 diabetes mellitus. Expert review of endocrinology & metabolism. 2018;13(5):263-72.
- Goday A, Bellido D, Sajoux I, Crujeiras AB, Burguera B, Garcia-Luna PP, et al. Short-term safety, tolerability and efficacy of a very low-calorie-ketogenic diet interventional weight loss program versus hypocaloric diet in patients with type 2 diabetes mellitus. Nutrition & diabetes. 2016;6(9):e230.
- Hussain TA, Mathew TC, Dashti AA, Asfar S, Al-Zaid N, Dashti HM. Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition. 2012;28(10):1016-21.
- O'Neill B, Raggi P. The ketogenic diet: Pros and cons. Atherosclerosis. 2020;292:119-26.
- Vranceanu M, Pickering C, Filip L, Pralea IE, Sundaram S, Al-Saleh A, et al. A comparison of a ketogenic diet with a LowGI/nutrigenetic diet over 6 months for weight loss and 18-month follow-up. BMC nutrition. 2020;6:53.