Now that ketogenic diets have become popular, many keto hybrid diets have sprung up, including plant-based versions. (One is “ketotarian,” which is predominantly plant-based but includes the option of eggs, ghee, and fish and shellfish.) While this approach can be healthy, Hultin cautions against trying keto as a vegan. “Because you can’t eat beans or lentils on a ketogenic diet, and nuts and seeds are even limited due to their carbohydrate content, you’re really just left with some tofu and will need to rely on low-carb protein powder,” she says. There is a good possibility this won’t pan out. “I don’t see this as a sustainable diet due to the extreme restrictions,” she says.
Our bodies are incredibly adaptive to what you put into it – when you overload it with fats and take away carbohydrates, it will begin to burn ketones as the primary energy source. Optimal ketone levels offer many health, weight loss, physical and mental performance benefits.1There are scientifically-backed studies that show the advantage of a low-carb, ketogenic diet over a low-fat diet. One meta-analysis of low-carbohydrate diets showed a large advantage in weight loss. The New England Journal of Medicine study resulted in almost double the weight loss in a long-term study on ketone inducing diets.

Keto and Traumatic Brain Injury (TBI): Research involving TBI has found that upon immediate trauma to the head, the brain takes up massive amounts of glucose. However, soon thereafter, the brain becomes resistant to taking up and utilizing glucose. This damage leads to insulin resistance and inflammation of brain tissue. The anti-oxidative and anti-inflammatory properties of ketones have been shown to not only reduce inflammation but to reduce glucose uptake in the brain as well. The ketogenic diet may also be a therapeutic treatment option for those individuals who have experienced long-term ramifications of a TBI by providing ketones as an alternative fuel source that can be readily taken up and utilized by the brain following these traumas.

Among the many biological modifications that must occur for sufficient ketone body utilization, the upregulation of ketone transporters must take place. Thus, research has demonstrated that chronic elevations in blood ketone levels positively increase the number of these transporters. Therefore adherence, especially during the initial stages of the keto diet for beginners, is critical.

How often you eat while on a keto diet plan is also up to your personal preference. "For most people, I recommend three to four meals per day with a few healthy keto snacks in between," says Dr. Axe. "This ensures that you're getting a good mix of protein and fat all day long to keep you feeling energized and satisfied." That being said, he encourages people to listen to their bodies and tune in to when they're truly hungry. "If you find that you feel better eating five to six smaller meals spread throughout the day, do what works best for you."


"Plenty of people jump right in, thinking all they have to do is cut carbs and increase fat. All of a sudden, they hit a wall and get 'keto flu.' They feel tired, lethargic, and experience headaches," Wittrock says. "The primary reason they get these symptoms is lack of the three primary electrolytes: sodium, potassium, and magnesium. If you're deficient in any of these, you'll suffer mentally and physically. This is the single biggest reason people fail on the keto diet."
It usually takes three to four days for your body to go into ketosis because you have to use up your body's stores of glucose, i.e., sugar first, Keatley says. Any major diet change can give you some, uh, issues, and Keatley says he often sees patients who complain of IBS-like symptoms and feeling wiped out at the beginning of the diet. (The tiredness happens because you have less access to carbs, which give you quick energy, he explains.)
Aude, Y., A. S, Agatston, F. Lopez-Jimenez, et al. “The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat: A Randomized Trial.” JAMA Internal Medicine 164, no. 19 (2004): 2141–46. doi: 10.1001/archinte.164.19.2141. jamanetwork.com/journals/jamainternalmedicine/article-abstract/217514.
Yes, they're technically a fruit, but we think olives deserve a shout-out all of their own, since they're also a great source of healthy fats and are one of a few keto-approved packaged foods. Plus, they're a great source of antioxidants, will satisfy your craving for something salty, and are blissfully low-carb. “About a palm's worth only has 3 grams of net carbs,” Sarah Jadin, RD, told Health in a previous interview.
A study with an intent-to-treat prospective design was published in 1998 by a team from the Johns Hopkins Hospital[20] and followed-up by a report published in 2001.[21] As with most studies of the ketogenic diet, no control group (patients who did not receive the treatment) was used. The study enrolled 150 children. After three months, 83% of them were still on the diet, 26% had experienced a good reduction in seizures, 31% had had an excellent reduction, and 3% were seizure-free.[Note 7] At 12 months, 55% were still on the diet, 23% had a good response, 20% had an excellent response, and 7% were seizure-free. Those who had discontinued the diet by this stage did so because it was ineffective, too restrictive, or due to illness, and most of those who remained were benefiting from it. The percentage of those still on the diet at two, three, and four years was 39%, 20%, and 12%, respectively. During this period, the most common reason for discontinuing the diet was because the children had become seizure-free or significantly better. At four years, 16% of the original 150 children had a good reduction in seizure frequency, 14% had an excellent reduction, and 13% were seizure-free, though these figures include many who were no longer on the diet. Those remaining on the diet after this duration were typically not seizure-free, but had had an excellent response.[21][22]
There are many ways in which epilepsy occurs. Examples of pathological physiology include: unusual excitatory connections within the neuronal network of the brain; abnormal neuron structure leading to altered current flow; decreased inhibitory neurotransmitter synthesis; ineffective receptors for inhibitory neurotransmitters; insufficient breakdown of excitatory neurotransmitters leading to excess; immature synapse development; and impaired function of ionic channels.[7]
Lastly, if you're active, you might need to make some adjustments to take that into account. "For the first one to two weeks, temporarily reducing your exercise load can be helpful as your body adjusts to being in ketosis," he says. "Additionally, for those who have an intense workout schedule, carb cycling may be a good option." Carb cycling essentially means you'll increase your carb intake on the days you're doing exercise, ideally just two to three days per week. "While low-carb days may be around 20 to 30 grams of net carbs daily, high-carb days can range all the way up to 100 grams, although it can vary based on your size and activity level," says Dr. Axe. (Related: 8 Things You Need to Know About Exercising on the Keto Diet.)
Instead of thinking about the total carbs you’re eating, assess what those carbs provide to you. Do the majority of your carbs come from fruit and vegetables, with a payload of fiber and disease-fighting antioxidants? Fantastic. Or are you consuming them in the form of added sugars (cookies, candy, soda) or refined flour? If you are, you know what to do.

Bonnie J. Brehm, Randy J. Seeley, Stephen R. Daniels, and David A. D’Alessio, “A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women,” The Journal of Clinical Endocrinology & Metabolism: Vol 88, No 4; January 14, 2009. http://press.endocrine.org/doi/full/10.1210/jc.2002-021480.


The ketogenic diet may seem like the Jekyll to the Hyde-like low-fat craze of the 1990s. The bulk of current research finds that the middle ground between the two extremes is more beneficial for overall health. Make it easy for yourself: Eat at least two servings a week of fatty fish (salmon, sardines, mackerel) and cook with a variety of quality fats (olive oil, canola oil, avocado oil) throughout the week.
Tracking protein is important for anyone who has adopted a ketogenic diet. Depending on activity level and other metabolic factors, some individuals may be able to tolerate more protein. As mentioned above, at a certain level protein can be glucogenic; so tailor it to your needs. However, we would say to lean towards more, not less, especially for older individuals trying to preserve muscle mass.
Increased Energy: Fat and ketone bodies can be utilized as a fuel source for nearly all of the cells in the body. Once the body begins to use ketones as its primary fuel source, there will be a noticeable increase in energy since you are avoiding the ups and downs associated with high-carbohydrate/high-glucose/high-insulin levels that result in feeling lethargic and tired throughout the day.
One area where food tracking can be especially helpful, though, is ensuring that you're hitting the right ratios of macronutrients-protein, carbs, and fat. "The most researched version of the ketogenic diet derives 70 percent of calories from healthy fats, 20 percent from protein, and only 10 percent from carbs," explains Charles Passler, D.C., nutritionist, and founder of Pure Change. "In the ideal world, each keto meal and snack should have that same (70/20/10) ratio of macronutrients, but studies have shown that you'll still achieve great results even if each meal varies slightly from that ratio, just as long as you don't exceed 50 grams per day of carbs, or eat those carbs in one sitting," says Passler. In order to achieve these ratios without a preset meal plan from a dietitian or doctor, some food tracking is probably going to be necessary. But once you get the hang of things, you may not need it anymore.
It seems strange that a diet that calls for more fat can raise “good” cholesterol and lower “bad” cholesterol, but ketogenic diets are linked to just that. It may be because the lower levels of insulin that result from these diets can stop your body from making more cholesterol. That means you’re less likely to have high blood pressure, hardened arteries, heart failure, and other heart conditions. It's unclear, however; how long these effects last.
If you “slip up” on a ketogenic diet, it is not the end-of-the-world nor does it mean you should continue to be off the wagon. Unfortunately, having frequent “slip-ups” or “cheat days” may prevent you from becoming “keto-adapted.” However, an occasional “slip-up” for someone who is already “keto-adapted” may not be as detrimental. Get back on track and get back in your routine. Find support groups and alternative recipes to avoid these pitfalls and setbacks.
On the ketogenic diet, carbohydrates are restricted and so cannot provide for all the metabolic needs of the body. Instead, fatty acids are used as the major source of fuel. These are used through fatty-acid oxidation in the cell's mitochondria (the energy-producing parts of the cell). Humans can convert some amino acids into glucose by a process called gluconeogenesis, but cannot do this by using fatty acids.[57] Since amino acids are needed to make proteins, which are essential for growth and repair of body tissues, these cannot be used only to produce glucose. This could pose a problem for the brain, since it is normally fuelled solely by glucose, and most fatty acids do not cross the blood–brain barrier. However, the liver can use long-chain fatty acids to synthesise the three ketone bodies β-hydroxybutyrate, acetoacetate and acetone. These ketone bodies enter the brain and partially substitute for blood glucose as a source of energy.[56]
Still, it can be hard to get enough fat when you first start this diet. Butter, nuts, coconut and olive oils, and fatty cuts of meat are all on the menu. However, don't go overboard with polyunsaturated fats like soybean, corn, or sunflower oil. Keto dieters who increase their intake of those fats often end up with gastrointestinal distress that causes them to jump ship.
Increased Energy: Fat and ketone bodies can be utilized as a fuel source for nearly all of the cells in the body. Once the body begins to use ketones as its primary fuel source, there will be a noticeable increase in energy since you are avoiding the ups and downs associated with high-carbohydrate/high-glucose/high-insulin levels that result in feeling lethargic and tired throughout the day.
Insulin is a hormone that lets your body use or store sugar as fuel. Ketogenic diets make you burn through this fuel quickly, so you don’t need to store it. This means your body needs -- and makes -- less insulin. Those lower levels may help protect you against some kinds of cancer or even slow the growth of cancer cells. More research is needed on this, though.
Also make sure that you know what foods have mostly carbs, fat, and protein, so you can make the right choices. For instance, it’s not just bread, pasta, chips, cookies, candy, and ice cream that contain carbs. Beans may contain protein, but they’re also very high in carbohydrates. Fruit and veggies also mostly contain carbs. The only foods that don’t contain carbs are meat (protein) and pure fats, like butter and oils (including olive oil and coconut oil). 
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