Do you keto? It seems that everyone is talking about the ketogenic diet these days. You may have seen celebrities, friends, and family members touting the health benefits of following a ketogenic diet, but how much do you really know about it?
If you’re curious about the ketogenic diet and wondering whether it might be the right approach for you, keep reading. We’re going to cover all of the basics regarding this diet, so you will be better able to make an informed choice about your nutrition strategy. By the end of this article, you’ll have answers to all things keto, including:
- What is a ketogenic diet?
- Which foods are included? Which are limited?
- Keto health benefits: what’s fact, what’s fiction?
- Are there risks associated with a ketogenic diet?
- Who should consider trying a ketogenic diet?
Before we begin, I’d like to remind readers that this article is for information purposes only and is not personal medical advice. If you find nutrition information online that you think is compelling, including in this article, it is important that you consult with your physician or dietitian before making major dietary changes. They know your medical history and can help you tailor a nutritional plan that is individualized to fit your needs.
What is a ketogenic diet?
There are six main nutrients that are part of the human diet: carbohydrates, proteins, fats, water, vitamins, and minerals. Most should aim to eat a diet that meets the Recommended Dietary Allowances (RDAs) for the essential vitamins and minerals; this is the intake level that will meet the needs of 97-98% of the healthy population.
However, there are many different macronutrient compositions (i.e., the percent of carbohydrate, protein, and fat in the diet) that will get a person to that goal. A simple definition of a ketogenic diet is that it is a diet that contains high fat, very low carbohydrate, and moderate protein.
The ketogenic diet has historically been used as medical nutrition therapy for intractable epilepsy, because the severe reduction in dietary carbohydrates forces the body to breakdown fat instead of glucose for energy, inducing a state of ketosis. This altered energy metabolism, as well as alterations in neurotransmitters, are hypothesized to be the potential mechanisms through which this diet can impact seizure control. People who are using the ketogenic diet to treat epilepsy typically need to keep tight macronutrient control under the direction of a medically supervised program to help ensure that they remain in ketosis.
Those using the ketogenic diet for weight loss rather than therapy for epilepsy have more freedom to play around with their macros to find the levels where they feel adequately satiated (full between meals). While those using keto for epilepsy may be prescribed macronutrient targets that are a percent of their total calorie intake, some using the diet for weight loss may choose not to track macros or ketone levels at all. Very low carbohydrate diets (VLCDs) often have a goal of 20-50 grams of carbohydrates per day to induce ketosis, but those using the diet for weight loss may choose to push their protein levels higher than is typical in epilepsy therapies if it helps them to feel full.
Which foods are included? Which are limited?
Technically, just about any food can fit within keto macros if it is cut into a small enough piece! Realistically, there are certain foods that tend to make up a more substantial part of the ketogenic diet, while others are severely limited or restricted.
The following are some mainstays of the ketogenic diet:
- Meat, poultry, seafood
- Full-fat dairy products (cheese, butter, heavy whipping cream, plain Greek yogurt)
- Oils (e.g., olive oil, coconut oil, avocado oil)
- Leafy greens (e.g., chard, romaine, spinach, beet greens)
- Cruciferous vegetables (e.g., cauliflower, broccoli, cabbage, Brussels sprouts)
- Other non-starchy vegetables (e.g., asparagus, cucumbers, celery, green beans, zucchini, summer squash)
- Some berries
- Nuts and nut butters
- Seeds and seed butters
- Herbs and spices
- Low-carb condiments (e.g., mayonnaise, mustard, and certain salad dressings)
- Yes, bacon also fits with this way of eating
Here are some foods that need to be severely limited or completely restricted on a ketogenic diet:
- Grains (including items made with grains, i.e., breakfast cereals, bread, grain-based desserts, pasta)
- Most fruits aside from some berries and the vegetables that are botanically fruits listed above (e.g., zucchini and cucumber)
- Starchy vegetables (e.g., root vegetables, tubers, corn, peas)
- Products with added sugars (including natural sugars like honey and maple syrup)
While the list of foods that should be limited may seem small at first, it is important to keep in mind that grain-based desserts and bread are the top two sources of calories in the American diet, with soda and energy drinks taking fourth place. When you remove all of these foods from your way of eating, your dietary pattern is likely to look extremely different than what you were formerly accustomed to.
Fiber and certain micronutrients may be low on this diet due to the restriction of foods containing carbohydrates, so supplementation may be recommended. Ketogenic diets for epilepsy are often supplemented with a multivitamin mineral that provides around 100% of the RDA for the essential nutrients.
Keto health benefits: what’s fact, what’s fiction?
There are many claims being made about the health benefits of the ketogenic diet online, which can make it difficult to discern fact from fiction. Currently, the most robust evidence for the use of the ketogenic diet as a therapeutic intervention is for certain patients with epilepsy, some with type 2 diabetes, or as a method of weight reduction. The use of the ketogenic diet may also improve specific cardiovascular risk parameters (specifically by lowering triglycerides and raising HDL cholesterol).
Major health organizations agree with these health benefits. The American Diabetes Association considers very low carbohydrate diets a “viable approach” for some individuals with type 2 diabetes. Perhaps not surprisingly, since the ketogenic diet restricts the high-carb cookies, cakes, bread, and other grain-based items that constitute a significant source of calories, the Academy of Nutrition and Dietetics recognizes low-carb diets as an evidence-based approach for weight loss as well as for epilepsy, as discussed above.
The above health conditions aside, claims that the ketogenic diet can treat everything from acne to more serious ailments like neurological diseases and cancer are emerging at best, and in some cases, the recommendations made by online health gurus may be dangerous. For example, though some may claim that the ketogenic diet may help treat or even cure cancer, the truth is that cancer is not a singular disease. In fact, there is evidence that certain types of cancer may even worsen with the use of the ketogenic diet, with increased tumor growth and progression.
Are there risks associated with a ketogenic diet?
The ketogenic diet is contraindicated for certain people, such as those with metabolic disorders that limit the metabolism of fats. Since the keto diet restricts certain food types and often leads to weight loss, it is also generally not recommended for the following people (unless part of a medically supervised nutrition therapy):
- Children and adolescents
- People who are underweight or ill
- People with a history of eating disorders
- Pregnant and breastfeeding women
- People already on medical nutrition therapy or those who are using certain medications
The “keto flu” is a common adverse effect in those initiating a ketogenic diet that typically only lasts a few days. This cluster of symptoms, including fatigue, headaches, and nausea, can occur as the body adapts to the change in diet. Ensuring adequate hydration as well as sufficient intake of electrolytes (particularly sodium) may help to mitigate these symptoms. Elevation of sodium excretion (also known as natriuresis) increases with nutritional ketosis, so it is important to replace this electrolyte as needed.
Some people experience an elevation in LDL cholesterol with the ketogenic diet, which may increase the risk of cardiovascular disease. However, there are ways to modify the diet to help lower LDL while remaining in ketosis, such as swapping out items high in saturated fat (such as coconut oil and butter) for unsaturated fats (such as olive oil and avocado oil). Another example of a good swap would be choosing omega-3 rich salmon instead of processed meats more often.
Who should consider trying a ketogenic diet?
Think you are ready to try a ketogenic diet? Here’s a handy checklist to help you determine whether you might be a good candidate:
- You have a health goal, such as weight loss, and are interested in using this way of eating as a tool to help. Know your why for changing your diet. What are you trying to accomplish?
- You have tried other approaches for weight management or blood sugar control in the past, and they did not work. If conventional approaches (e.g., calorie tracking, carbohydrate-controlled diets) did not help you to reach your goals in the past, it might be time to experiment with a different strategy such as the ketogenic diet.
- Your doctor gave you the green light. Having your physician review your medical history is a smart move before initiating this diet. Certain medications that do not mix well with keto may need to be modified.
- You recently had a complete physical exam, including labs, so that you and your physician can monitor changes that are taking place. Another good move is to have some baseline measurements taken so that you can see how this diet is impacting you. A current weight, blood pressure, lipid panel (cholesterol levels), and (for those with type 2 diabetes) A1C are some suggested items to measure both before initiation and at regular intervals after starting a ketogenic diet.
- You are accepting of taking on the potential risks and willing to tolerate the possible discomforts that are associated with this way of eating. Are you willing to go through the “keto flu”? Are you comfortable with the relative lack of data regarding the potential for long-term health risks with this diet?
- You enjoy foods that are mainstays of the ketogenic diet and find a higher fat macronutrient composition filling. Do you enjoy rich meals of savory whole foods? Creating a well-formulated diet with a variety of keto-friendly whole foods will best help you to meet your micronutrient needs.
- Limiting the foods that do not align well with the keto diet does not make you feel overly restricted. This way of eating will not help you meet your health goals if you cannot sustain it.
- You are prepared to make a lifestyle change. Aside from being ready to make this change, it is also a good idea to tell those closest to you about your plans and ask for their support. You may even find someone willing to make these changes with you.
- You have a backup plan if this way of eating does not end up being a good fit for you. A wise dietitian once said that if you keep cheating on your diet, it just might be time to break up. Rather than throwing in the towel on your health goals, have a “plan B” in place so that you can keep moving forward in your health journey.
There is no one-size-fits-all when it comes to weight loss, so please keep in mind that what worked well for a family member or celebrity may not be what is the best approach for you. If you are feeling a bit lost with your nutrition and need additional help, consider making an appointment with a registered dietitian who is supportive of your health goals. We love to see clients succeed, whether through the use of the ketogenic diet or another way of eating!
Summer is a registered dietitian located in Avon, Connecticut where she specializes in weight management, special diets, general nutrition, and avoidant/restrictive food intake disorder (ARFID). She is the developer and content creator behind the Summer Yule Nutrition website, where she shares evidence-based information on hot topics in food and nutrition.