The brain is composed of a network of neurons that transmit signals by propagating nerve impulses. The propagation of this impulse from one neuron to another is typically controlled by neurotransmitters, though there are also electrical pathways between some neurons. Neurotransmitters can inhibit impulse firing (primarily done by γ-aminobutyric acid, or GABA) or they can excite the neuron into firing (primarily done by glutamate). A neuron that releases inhibitory neurotransmitters from its terminals is called an inhibitory neuron, while one that releases excitatory neurotransmitters is an excitatory neuron. When the normal balance between inhibition and excitation is significantly disrupted in all or part of the brain, a seizure can occur. The GABA system is an important target for anticonvulsant drugs, since seizures may be discouraged by increasing GABA synthesis, decreasing its breakdown, or enhancing its effect on neurons.[7]
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]

In general, a low-carb diet focuses on proteins, including meat, poultry, fish and eggs, and some nonstarchy vegetables. A low-carb diet generally excludes or limits most grains, legumes, fruits, breads, sweets, pastas and starchy vegetables, and sometimes nuts and seeds. Some low-carb diet plans allow small amounts of certain fruits, vegetables and whole grains.
That said, it’s a good idea to work with a doctor or registered dietitian before you start eating keto—and continue to check in with them while you adapt to your new diet, recommends David Nico, PhD, author of Diet Diagnosis. Planning ahead can help you steer clear of nutritional deficiencies that can strike when you cut most carbs out of your diet. And doing so might also help minimize your keto flu symptoms.
Adopting a ketogenic diet may also hamper athletic performance, says Weiss, even though many athletes try it, thinking it will have the opposite effect. In a recent study in the Journal of Sports Medicine and Physical Fitness, Weiss and his colleagues found that after four days on a keto diet, participants performed worse on anaerobic exercise tasks—which involve short bursts of intense activity—than those who’d recently gone on a high-carb diet.
Not everyone should opt for a low-carb diet. If you’re pregnant, it’s possible to be on a lower-carb diet (and may even be indicated if you are told you have gestational diabetes), but talk to your doctor to find out what’s right for you and to ensure that you’re covering any potential nutrient gaps. “Many women who are pregnant find that the thought of eating protein and fat makes them sick,” says Spritzler. This can be especially common in the first trimester. “They naturally want more carbs. You should always listen to your body,” she says.
"Your body will often shift metabolism when you do something different to it -- but it equalizes -- you see a rapid shift and a return to normal -- and the longer-term studies show normal results in this area," says Sondike. Still, he tells WebMD it's a "smart idea" to take a calcium supplement beginning at the start of your low-carb diet to safeguard against a possible deficiency. Tofu can also be a good source of calcium.
Normal dietary fat contains mostly long-chain triglycerides (LCTs). Medium-chain triglycerides (MCTs) are more ketogenic than LCTs because they generate more ketones per unit of energy when metabolised. Their use allows for a diet with a lower proportion of fat and a greater proportion of protein and carbohydrate,[18] leading to more food choices and larger portion sizes.[4] The original MCT diet developed by Peter Huttenlocher in the 1970s derived 60% of its calories from MCT oil.[15] Consuming that quantity of MCT oil caused abdominal cramps, diarrhea, and vomiting in some children. A figure of 45% is regarded as a balance between achieving good ketosis and minimising gastrointestinal complaints. The classical and modified MCT ketogenic diets are equally effective and differences in tolerability are not statistically significant.[9] The MCT diet is less popular in the United States; MCT oil is more expensive than other dietary fats and is not covered by insurance companies.[18]
Vegetables that grow above ground: Cauliflower, broccoli, cabbage and Brussels sprouts, kale, collards, bok choy, spinach, asparagus, zucchini, eggplant, olives, spinach, mushrooms, cucumber, avocado, onions, peppers, tomatoes, lettuce, other kinds of leafy greens etc. These are lowest in net carbs and can be enjoyed at all levels of carb restriction. However, if you are following a keto diet (< 20 grams of carbs per day), you may need to limit your portions for certain types, like bell peppers and Brussels sprouts. Low-carb vegetables guide
When you’re eating the foods that get you there (more on that in a minute), your body can enter a state of ketosis in one to three days, she adds. During the diet, the majority of calories you consume come from fat, with a little protein and very little carbohydrates. Ketosis also happens if you eat a very low-calorie diet — think doctor-supervised, only when medically recommended diets of 600 to 800 total calories.
Stock up: The Amazon Fresh grocery delivery service makes it easy to ensure you always have keto-friendly veggies in the fridge. We love its delivery scheduling tool; simply fill your cart, then decide which day and timeframe you'd like your groceries delivered. One of our faves: Pre-Cut Zucchini Noodles are great for whipping up low-carb "pasta" dishes.
Fruit: While berries like blueberries, raspberries and strawberries are fine in small to moderate amounts, be careful with other fruit. They are fairly high in carbs and sugar, which can raise blood sugar, may slow down weight loss and can possibly worsen metabolic issues. Consider it nature’s candy: fine for a special treat, but probably not something to consume daily on a low-carb diet. Learn more 
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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.
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