The nerve impulse is characterised by a great influx of sodium ions through channels in the neuron's cell membrane followed by an efflux of potassium ions through other channels. The neuron is unable to fire again for a short time (known as the refractory period), which is mediated by another potassium channel. The flow through these ion channels is governed by a "gate" which is opened by either a voltage change or a chemical messenger known as a ligand (such as a neurotransmitter). These channels are another target for anticonvulsant drugs.
On a ketogenic diet, you’re generally eating a diet that’s high in fat (roughly 70 percent of your total calories come from fat), moderate in protein (about 20 percent of your calories), and low in carbohydrate (about 5 percent of calories). By limiting carbohydrates (to usually less than 45 grams for the average person), your body lacks the glucose (from carbs) that it normally uses for energy, so it eventually switches over to burning fat as its primary fuel source instead; through a metabolic process called ketosis, the liver converts the fat into fragments of fatty acids called ketones, which power the brain and other organs and tissues.
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.
What's more, it's especially important to make sure your keto diet plan is well thought out when you're eating this way because the foods you can choose from are limited. In addition to checking in with a dietitian if you're able, Stefanski recommends that you "talk to your doctor and make sure she or he is aware that you'll be starting a diet that completely changes how your body metabolizes energy." You might also want to check your most recent bloodwork levels for things such as cholesterol, vitamin D, and other indicators of health because these can change while on keto. That's because, for some people, a prolonged keto diet can result in certain nutritional deficiencies or even high cholesterol. But most experts will tell you that the ketogenic diet is not a permanent lifestyle change (as could be the case for something like the 80/20 approach to eating or a Mediterranean eating style).
Restricting your calories may be important for some individuals depending on their goals. Additionally, it may aid in the initiation of ketosis; however, not everyone will require calorie tracking to maintain a deficit. It is not uncommon for caloric-restriction to occur inadvertently as a ketogenic diet tends to be satiating, leaving individuals satisfied with fewer calories.
“People are afraid of fat because they’ve been told that it’ll kill them,” says Mancinelli. What is confusing is that research today remains mixed. Some studies suggest that replacing saturated fat with polyunsaturated fat (and avoiding unhealthy trans fat) is important for mitigating heart disease risk, while others suggest that total fat and types of fat weren’t associated with cardiovascular problems, according to an article published in June 2018 in BMJ. (2) Deciding exactly how to eat then becomes confusing. What is helpful, the authors note, is to remember that food is more than a single nutrient, and it’s the overall quality of the diet that counts. (They do say that high-fat, low-carb diets still need more research to assess their long-term health benefits and risks.)
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)
Blood Lipids on a Ketogenic Diet: Lack of proper education has incorrectly held a high-fat diet responsible for an increase in blood lipids. Decades of research, combined with efforts to shift the paradigm, are now revealing that increased dietary fat consumption does not directly result in increased blood lipids. It is actually carbohydrate consumption that tends to increase total cholesterol with noticeable decreases in the HDL “good” cholesterol. Often, researchers use a “high-fat diet” interchangeably with a “Western diet;” many confuse the term “high-fat diet” in the research with a ketogenic diet. A “high-fat diet” in the research indicates a diet with both high-fats and high-carbs, which is associated with increased blood lipids, whereas a ketogenic diet is not.
Electrolytes: Due to the increased water expulsion by the kidneys, many electrolytes are simultaneously lost. Electrolyte imbalances are heavily responsible for feeling the “keto-flu.” Important electrolytes one must consider replacing: sodium, potassium, and magnesium. These electrolytes can be replenished by increasing your intake of certain foods and/or supplementation.
Ready to head out the door and start buying groceries? Slow down there, chief. Go through the pantry, fridge, freezer, and secret stashes under the bed, and get rid of foods with any significant carb content. In the first few days, you could end up craving them—badly. This means fruit, too. Even carrots and onions are too high-glycemic to work with keto, Wittrock says.
Ketogenesis has existed as long as humans have. If you eat a very low amount of carbohydrates, you starve your brain of glucose, its main fuel source. Your body still needs fuel to function, so it taps into your reserve of ketones, which are compounds the liver creates from fat when blood insulin is low. This process is known as ketosis: It’s like when a hybrid car runs out of gas and reverts to pure electricity.
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.)
Breath Ketone Analysis: This method analyzes an individual’s breath to determine whether or not they are producing ketones, specifically, acetone. While this method has also been found to be an effective indicator, more research needs to be done to examine how this compares to blood testing. Studies investigating breath analyzers have found that these devices serve as a reliable indicator of ketosis.
Achieving optimal ketosis hinges on finding the right balance of macronutrients (or “macros” in keto-speak); these are the elements in your diet that account for the majority of your calories, a.k.a. energy—namely, fat, protein, and carbohydrates. By the way, it’s often “net grams” of carbohydrates that are counted toward your daily intake; “net” deducts the amount of fiber in a food from its carbohydrate total.