When adopting a keto diet for beginners, ensuring that it has been “well-formulated” is indispensable. Unfortunately, this critical factor is often overlooked and makes adherence to this diet very difficult. In addition, taking into consideration food quality and micronutrients are also just as critical. A well-formulated ketogenic diet will also aid in the prevention or alleviation of the side effects/”keto-flu” that are often experienced with the keto-adaptation process. To help create a well-formulated ketogenic diet, some points of consideration are outlined below:
For patients who benefit, half achieve a seizure reduction within five days (if the diet starts with an initial fast of one to two days), three-quarters achieve a reduction within two weeks, and 90% achieve a reduction within 23 days. If the diet does not begin with a fast, the time for half of the patients to achieve an improvement is longer (two weeks), but the long-term seizure reduction rates are unaffected.[44] Parents are encouraged to persist with the diet for at least three months before any final consideration is made regarding efficacy.[9]
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]

Once “keto-adapted,” many tissues increase their capacity to utilize ketones for fuel. Some tissues even prefer to use ketones for their cellular energy needs. For instance, the heart, as well as many areas of the brain, prefers to use ketone bodies as opposed to glucose. One interesting fact is that Dr. Stephen Cunnane found that the uptake of ketone bodies in the brain is proportional to their production.[12] Additional research has also demonstrated that as uptake of ketones increases, the uptake of glucose decreases in brain tissue.[13][14] In contrast, there are certain cells that cannot use fatty acids or ketone bodies, and are considered “obligate glucose users.” Red blood cells and specific parts of the brain are obligate glucose users. Don’t stress, however, because even though you may not be consuming a lot of carbohydrates, these cells can obtain glucose through a biological process called gluconeogenesis (the production of glucose from other non-glucose materials).
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.
Just because you're not eating all your fave carb-y foods, that doesn't mean you're going to go hungry. You'll be loading up on healthy fats (like olive oil and avocado), along with plenty of lean protein like grass-fed beef and chicken, and leafy greens or other non-starchy veggies. (Check out this printable keto diet grocery list, plus this additional comprehensive list of keto foods recommended by nutritionists, to get started.)

In addition, there are medical conditions that should make you think twice about starting keto — or at least talk to your doctor before trying it out. Those include people on insulin, as well as those on oral and noninsulin injectable medications for high blood sugar or high blood pressure, says Hultin. Even struggling with GI issues may be a barrier to starting. “One of the side effects of a ketogenic diet is constipation, so if that’s a struggle, there’s serious reason not to go on this relatively low-fiber diet,” says Hultin. Last consideration: If existing personal dietary restrictions require you to avoid foods like soy, eggs, nuts, dairy, or seafood, a ketogenic diet may be too limiting for you. Coming from a place of elimination in an already restrictive diet can make it incredibly tough to follow, she says.
This can look different for everybody, but some popular forms of this are the 16:8 diet, where you fast for 16 hours (usually from dinnertime until a late breakfast) and eat all your food within an eight-hour span. Another is the 5:2 diet, where you eat less than 500 calories for two non-consecutive days a week and then eat normally for the rest of the week.
The modified Atkins diet reduces seizure frequency by more than 50% in 43% of patients who try it and by more than 90% in 27% of patients.[18] Few adverse effects have been reported, though cholesterol is increased and the diet has not been studied long term.[48] Although based on a smaller data set (126 adults and children from 11 studies over five centres), these results from 2009 compare favorably with the traditional ketogenic diet.[18]
Keto for Cancer: Cancer is now being discussed as primarily a metabolic disease in which glucose can fuel its progression. Due to recent light shed on this subject, intensive investigations are underway and have begun to reveal that restricting carbohydrate intake can slow oncogenesis and that a full ketogenic-state may elicit even greater therapeutic benefits. Furthermore, research also suggests that fasting and the state of ketosis may increase the sensitivity of cancer cells to radiation and chemotherapy.
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.
H. Guldbrand, B. Dizdar, B. Bunjaku, T. Lindström, M. Bachrach-Lindström, M. Fredrikson, C. J. Östgren, F. H. Nystrom, “In Type 2 Diabetes, Randomisation to Advice to Follow a Low-carbohydrate Diet Transiently Improves Glycaemic Control Compared with Advice to Follow a Low-fat Diet Producing a Similar Weight Loss,” Diabetologia (2012) 55: 2118. http://link.springer.com/article/10.1007/s00125-012-2567-4.

I eat relatively healthy and fairly low carb (I am already gluten free). I am interested in getting into Ketosis for the the health benefits, but am quite thin for a guy and don’t want to lose any weight. I look at the sample diet above and am pretty sure I would drop weight quickly (I consume about 2,500+ calories daily now). I eat 3 meals plus 2-3 snacks (snacks mostly of nuts (with raisins that would have to go), greek yogurt (would switch to plain), peanut butter, cheese and fruit (would need to reduce qty)). Would eating straight up butter be ok for additional calories also once I am in Ketosis?