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.
Wondering what fits into a keto diet — and what doesn’t? “It’s so important to know what foods you’ll be eating before you start, and how to incorporate more fats into your diet,” says Kristen Mancinelli, RD, author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss, who is based in New York City. We asked her for some guidelines.

While it may be new to you, the keto diet has actually been around since the 1920’s, when the Mayo Clinic reported its effectiveness for helping epilepsy (that is still the case). Since then, there’s strong evidence that the keto diet helps with weight loss as well as type 2 diabetes, prediabetes, and metabolic syndrome, says Jeff Volek, Ph.D., RD, professor in the department of Human Sciences at The Ohio State University in Columbus, Ohio and co-author of The Art and Science of Low Carbohydrate Living.
Unfortunately, it has been ingrained into society that consuming dietary fat is detrimental to our health. Due to early “research” by individuals such as Ancel Keys, these concepts have plagued our perceptions of dietary fat for several decades. Dietary fat, when consumed alone, isn’t the culprit for bad health, but rather it is the pairing of high amounts of fat and high amounts of carbohydrates in meals (i.e., fast food) driving the issues. This high fat and carb combination has led to the many serious health problems we face today, giving rise to the quote, “Don’t blame the butter for what the bread did.”
When it comes to starting the keto diet (or any diet for that matter), there's one thing all experts agree on. You *must* have a plan. "Never try to wing a keto diet," says Julie Stefanski, R.D.N., C.S.S.D., L.D.N., a dietitian based in York, PA, who specializes in the ketogenic diet. "Set a start date and get prepared by reorganizing your pantry, planning out meal and snack options, and purchasing appropriate foods and dietary supplements," she says. "The biggest reason people have a hard time sticking with keto is that people don't have enough interesting foods to turn to, and high-carb favorites win out over good intention. If you didn't buy foods at the grocery store that fit the guidelines, there won't be an easy option in the fridge when you really need it." (A great place to start is this List of High-Fat Keto Foods Anyone Can Add to Their Diet.)
The ketogenic diet is a medical nutrition therapy that involves participants from various disciplines. Team members include a registered paediatric dietitian who coordinates the diet programme; a paediatric neurologist who is experienced in offering the ketogenic diet; and a registered nurse who is familiar with childhood epilepsy. Additional help may come from a medical social worker who works with the family and a pharmacist who can advise on the carbohydrate content of medicines. Lastly, the parents and other caregivers must be educated in many aspects of the diet for it to be safely implemented.[5]
When in the hospital, glucose levels are checked several times daily and the patient is monitored for signs of symptomatic ketosis (which can be treated with a small quantity of orange juice). Lack of energy and lethargy are common, but disappear within two weeks.[17] The parents attend classes over the first three full days, which cover nutrition, managing the diet, preparing meals, avoiding sugar, and handling illness.[19] The level of parental education and commitment required is higher than with medication.[44]
As with other facets of the keto diet for beginners, the optimal ketone levels will vary on an individual basis. However, literature typically suggests that mild nutritional ketosis will begin once blood ketones are around 0.3–0.5 mmol/L. Upon “keto-adaptation,” this value may increase to around 1.0–3.0 mmol/L; however, that’s not always necessarily the case. If an individual is following a ketogenic diet strictly for therapeutic reasons, one may consider trying to achieve a deeper level of ketosis, but even those with a strict regimen may see only slight elevations in ketones due to rapid uptake into tissues.
The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]

Tip: Consuming a moderate dose of exogenous ketones during the initial “keto-adaptation” period could potentially accelerate the “adaptation,” while at a minimum increasing energy production. Once one is adapted, these products are excellent for achieving higher blood-ketone levels, which, in turn, can be beneficial for athletic and cognitive performance, energy production, and perhaps more effective therapeutic treatment.
The most science-backed performance-boosting supplements, such as creatine monohydrate, beta-alanine, and caffeine, are all A-OK on the ketogenic diet. So, if you take a pre-workout, you should be able to continue without issue. I would also recommend gulping down some bouillon before your session to ensure your sodium and magnesium levels are on point.
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]
Eggs are a healthy, nutrient-dense food that has been incorrectly maligned for years. Cholesterol in food doesn’t increase cholesterol in your blood, so eat eggs liberally – they’re packed with protein and lutein, and they fill you up for hours. Make a healthy omelet with some cheddar, crumbled breakfast sausage, and shredded spinach and you’re already looking at over 30g of protein, just for breakfast! Spinach is a great source of magnesium and potassium, too. Add some sea salt and you’ve got a big dose of electrolytes that are so vital to maintaining energy and staving off headaches. Get the recipe and instructions

Unfortunately, it has been ingrained into society that consuming dietary fat is detrimental to our health. Due to early “research” by individuals such as Ancel Keys, these concepts have plagued our perceptions of dietary fat for several decades. Dietary fat, when consumed alone, isn’t the culprit for bad health, but rather it is the pairing of high amounts of fat and high amounts of carbohydrates in meals (i.e., fast food) driving the issues. This high fat and carb combination has led to the many serious health problems we face today, giving rise to the quote, “Don’t blame the butter for what the bread did.”


Diabetic Ketoacidosis: Diabetic ketoacidosis (DKA) is the variation of ketosis that is responsible for deterring society from considering the adoption of a keto diet for beginners. DKA occurs primarily in those suffering from Type 1 diabetes. The inability to secrete insulin prevents ingested carbohydrates (glucose) from entering our insulin-dependent cells (i.e., muscle and adipose tissue) as a substrate for energy production. Due to this induced cellular starvation, the body will begin to produce ketones at an uncontrolled rate.
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.
Another difference between older and newer studies is that the type of patients treated with the ketogenic diet has changed over time. When first developed and used, the ketogenic diet was not a treatment of last resort; in contrast, the children in modern studies have already tried and failed a number of anticonvulsant drugs, so may be assumed to have more difficult-to-treat epilepsy. Early and modern studies also differ because the treatment protocol has changed. In older protocols, the diet was initiated with a prolonged fast, designed to lose 5–10% body weight, and heavily restricted the calorie intake. Concerns over child health and growth led to a relaxation of the diet's restrictions.[19] Fluid restriction was once a feature of the diet, but this led to increased risk of constipation and kidney stones, and is no longer considered beneficial.[18]

The ketogenic diet — a high-fat and very low carb eating plan — can be tough to start. After all, it’s likely a radical departure from the way you’re eating now (a typical standard American diet is high in carbohydrates and processed foods). But many people are trying the keto diet, which puts your body in a state of ketosis. That's what happens when your body’s carb-burning switch flips to a fat-burning one, a change that can cause weight loss and has even been credited with controlling type 2 diabetes, a small past study suggests. (1)
Keto for Alzheimer’s Disease: One characteristic of Alzheimer’s disease is insulin resistance in the brain (hence why it’s now being referred to as type III diabetes), which robs this critical tissue of energy. Limiting glucose while introducing ketones may be an effective mechanism for replenishing the energy in the tissue. The higher level of ketone production accompanied with a ketogenic diet is another example as to why this diet is superior to one that simply restricts carbohydrate intake. Additionally, Alzheimer’s disease is characterized by beta-amyloid deposition, which may also be mitigated by the implementation of a ketogenic diet.
Meat products make up a big part of the keto diet, but experts stress the importance of choosing quality. "Since the keto diet is based a lot on animal proteins, it's important to buy organic poultry and grass-fed, organic beef," says Aimee Aristotelous, RD. "Not only do organic selections help with limiting environmental toxins, but grass-fed options of red meats even change the composition of fats." The result, she explains, is that your body is able to better absorb those healthy fats.
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.
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence was inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]
One thing many people love about keto diet plans is that tracking your food is optional. "One of the biggest benefits of the ketogenic diet is that there's no need to meticulously track your calories as you may in other diets," notes Dr. Josh Axe, D.N.M., C.N.S., D.C., founder of DrAxe.com, best-selling author of Eat Dirt, and cofounder of Ancient Nutrition. "Because you're filling up on fat and protein, you're more likely to feel satisfied and energized all day long, which causes you to naturally eat less." This isn't to say that food tracking on a keto meal plan is discouraged. "Some people may find calorie counting a useful tool to be more mindful and aware of what they're eating, but it's not necessary on the ketogenic diet," says Dr. Axe, but there's no need to get too stressed about hitting a certain caloric goal, especially if you're not trying to lose weight. (Related: The #1 Reason to Stop Counting Calories)
Bulk buy and cook. If you’re someone who doesn’t like to spend a lot of time in the kitchen, this is the best of both worlds. Buying your food at bulk (specifically from wholesalers) can reduce the cost per pound tremendously. Plus, you can make ahead food (bulk cook chicken thighs for pre-made meat, or cook entire meals) that are used as leftovers, so you spend less time cooking.
Run by the Charlie Foundation, this calculator can be helpful when you’re using keto as a therapy to help manage a medical condition. The calculator helps estimate calorie needs based on weight, assists in determining a macro ratio and macros needed per meal, and can calculate macro numbers on the basis of meals and snacks you enter into the system. Also takes into account fluids, supplements, and medications.
No matter what your diet has been before now, keto will be a big change. If you're coming from a standard American diet (SAD), your carbs will go way down, your protein may either go up or down, and your fat will go way up. If you're coming from a bodybuilding-style diet, your fat intake will jump to alarming levels, and your protein will likely drop significantly.

^ Freeman JM, Vining EP, Pillas DJ, Pyzik PL, Casey JC, Kelly LM. The efficacy of the ketogenic diet—1998: a prospective evaluation of intervention in 150 children. Pediatrics. 1998 Dec;102(6):1358–63. doi:10.1542/peds.102.6.1358. PMID 9832569. https://web.archive.org/web/20040629224858/http://www.hopkinsmedicine.org/press/1998/DECEMBER/981207.HTM Lay summary]—JHMI Office of Communications and Public Affairs. Updated 7 December 1998. Cited 6 March 2008.
Run by the Charlie Foundation, this calculator can be helpful when you’re using keto as a therapy to help manage a medical condition. The calculator helps estimate calorie needs based on weight, assists in determining a macro ratio and macros needed per meal, and can calculate macro numbers on the basis of meals and snacks you enter into the system. Also takes into account fluids, supplements, and medications.

Wilder's colleague, paediatrician Mynie Gustav Peterman, later formulated the classic diet, with a ratio of one gram of protein per kilogram of body weight in children, 10–15 g of carbohydrate per day, and the remainder of calories from fat. Peterman's work in the 1920s established the techniques for induction and maintenance of the diet. Peterman documented positive effects (improved alertness, behaviour, and sleep) and adverse effects (nausea and vomiting due to excess ketosis). The diet proved to be very successful in children: Peterman reported in 1925 that 95% of 37 young patients had improved seizure control on the diet and 60% became seizure-free. By 1930, the diet had also been studied in 100 teenagers and adults. Clifford Joseph Barborka, Sr., also from the Mayo Clinic, reported that 56% of those older patients improved on the diet and 12% became seizure-free. Although the adult results are similar to modern studies of children, they did not compare as well to contemporary studies. Barborka concluded that adults were least likely to benefit from the diet, and the use of the ketogenic diet in adults was not studied again until 1999.[10][14]


Sharon M. Nickols-Richardson, PhD, RD, , Mary Dean Coleman, PhD, RD, Joanne J. Volpe, Kathy W. Hosig, PhD, MPH, RD, “Perceived Hunger Is Lower and Weight Loss Is Greater in Overweight Premenopausal Women Consuming a Low-Carbohydrate/High-Protein vs High-Carbohydrate/Low-Fat Diet,” The Journal of Pediatrics: Vol 105, Issue 9: 1433–1437; September 2005. http://www.sciencedirect.com/science/article/pii/S000282230501151X.
When you eat less than 50 grams of carbs a day, your body eventually runs out of fuel (blood sugar) it can use quickly. This typically takes 3 to 4 days. Then you’ll start to break down protein and fat for energy, which can make you lose weight. This is called ketosis. It's important to note that the ketogenic diet is a short term diet that's focussed on weight loss rather than the pursuit of health benefits. 
It can take many weeks for someone to notice differences. If you’re weight training and doing the diet you may not notice weight loss immediately because you are growing muscle and muscle is heavier than fat. Elsewise, for me I went really strict starting out. I did under 30 carbs a day for the first week and measured my ketone levels with the piss sticks you can buy at cvs and was entering ketosis after 3 days. I went up to 40 carbs a day for the next 3 months and lost 60lbs of fat. I was 287 lbs and weighed in at 227 when I finished. Mind you I exercised daily doing heavy weight training and intermediate cardio. The diet does work though. I did put on lean muscle while getting down to a healthy weight for my height. It helped with my panic disorder as well as giving me a lot of energy.

Sleep enough – for most people at least seven hours per night on average – and keep stress under control. Sleep deprivation and stress hormones raise blood sugar levels, slowing ketosis and weight loss a bit. Plus they might make it harder to stick to a keto diet and resist temptations. So while handling sleep and stress will not get you into ketosis on its own, it’s still worth thinking about.
Cognitive Enhancement: Ketones may be the preferred fuel source for the brain. Due to the brain’s preference to uptake and utilize ketones as fuel it is very common for individuals to report an increase in cognitive performance. This is even more common in individuals with some degree of insulin resistance, as their brain is likely unable to effectively utilize glucose as a sole fuel source due to the resistance.
Around this time, Bernarr Macfadden, an American exponent of physical culture, popularised the use of fasting to restore health. His disciple, the osteopathic physician Dr. Hugh William Conklin of Battle Creek, Michigan, began to treat his epilepsy patients by recommending fasting. Conklin conjectured that epileptic seizures were caused when a toxin, secreted from the Peyer's patches in the intestines, was discharged into the bloodstream. He recommended a fast lasting 18 to 25 days to allow this toxin to dissipate. Conklin probably treated hundreds of epilepsy patients with his "water diet" and boasted of a 90% cure rate in children, falling to 50% in adults. Later analysis of Conklin's case records showed 20% of his patients achieved freedom from seizures and 50% had some improvement.[10]
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