Over the past five years, the ketogenic diet (aka the keto diet) has skyrocketed in popularity. In 2020, no other diet was mentioned more often in Google search queries — not gluten-free, vegan or Paleo. For a diet that was discovered as a treatment for epilepsy in the 1920s that’s quite the meteoric rise. 
So, why is everyone suddenly going crazy for keto?
What the heck is ketosis?
What are the best low-carb, high-fat foods to eat?
Questions, meet answers. From health benefits to the best low-carb, high-fat food options, read on to discover everything you need to know about keto. Let’s start from the top, shall we?
When was the Keto Diet Invented?
Since 500 B.C., fasting and other diets have been used to treat epilepsy. Then, in 1924, the keto diet was introduced by Dr. Russell Wilder from the Mayo Clinic as a new treatment for epilepsy. It continued to be used over the next two decades until the invention of antiepileptic drug treatments.
By the conclusion of the 20th century, it was only used as a treatment for epilepsy in a small number of children’s hospitals. Then, boom! The century turned, and it made a comeback as a weight loss diet. 
What is the Keto Diet?
The keto diet is a low-carb, high-fat diet designed to put the body into a metabolic state known as ketosis. In ketosis, the liver produces higher levels of ketones through the digestion of fat. Typically, the body and brain’s primary fuel source is glucose, but the body lacks enough glucose to properly fuel itself when following a very low-carb diet. Instead, the body is forced to burn fat for fuel, producing ketones.
To reach ketosis, you need to reduce your carb intake and eat more healthy fats. Ketosis happens when the liver breaks down fat into fatty acids and glycerol through beta-oxidation. These fatty acids are further broken down into energy-rich substances called ketone bodies that circulate through the bloodstream. Once the blood levels of a ketone rise to a certain point, you officially enter ketosis. Ketosis is responsible for all the health benefits that have led to the keto diet’s unparalleled popularity! 
When it comes to caloric restrictions, the keto diet doesn’t differ from most other diets. Keto dieters should determine their daily caloric intake by their weight, activity level, lifestyle and goals. The big difference with keto is the requirements for daily macronutrients: fat, carbs and (to a lesser degree) protein.
What Should My Daily Macronutrients be on Keto?
Fat should make up 65 to 75% of your overall daily calorie intake on the keto diet. Each gram of fat contains nine calories, so a person following a 2,000-calorie diet would consume around 156 grams of dietary fat.
Carbohydrates should only make up 5 to 10% of your overall daily calorie intake on the keto diet. Each gram of carbohydrate has four calories. In a 2000 calorie diet, 10% of the calories is roughly 50 grams of carbohydrates.
Net carbs are carbohydrates that your body is able to use as energy. Since the body doesn’t digest dietary fiber and sugar alcohols, they don’t cause a rise in blood glucose. Therefore, you can subtract them from your total carbohydrates to calculate net carbs.
Protein intake should account for about 20% of your overall daily calorie intake. Each gram of protein contains four calories. Based on a 2,000-calorie diet, 20% is around 100 grams of protein.
What are the Benefits of the Keto Diet?
Further research is needed to understand the health benefits of the keto diet fully. However, studies show that the keto diet may help with weight loss, skin health, neuroprotective health, appetite management and sugar craving suppression. 
How Long Does it Take to go Into Ketosis?
The time it takes to reach ketosis varies from person to person. However, generally speaking, it takes anywhere from a few days to over a week to reach ketosis.
The time it takes to reach ketosis can also vary based on how quickly you cut carbs and increase your fat intake. Age, metabolism, lifestyle, daily physical activity and past nutrition habits can also play a role.
When first starting keto, be sure to test your body for ketones to see when you reach a state of ketosis. There are three main ways to check for ketones: blood testing, breath testing and urine testing. 
If it takes longer than expected to reach ketosis, consider further restricting your carbohydrate intake in favor of healthy fats. If that doesn’t work, consider trying intermittent fasting.
Intermittent fasting is a pattern of eating that alternates between periods of fasting and periods of eating. The fasting period can help deplete your body’s glycogen stores to help it start utilizing fat as fuel. 
Successful keto dieters know which foods are keto-friendly! To help you learn the ropes, here’s a list of dietitian-recommended foods for your keto meal plan.
- Pork rinds (1 oz): 0 grams net carbs, 10 grams fat, 18 grams protein.
- Full-fat string cheese (1 stick): 0 grams net carbs, 6 grams fat, 7 grams protein.
- Sardines in oil (1 oz): 0 grams net carbs, 3 grams fat, 6.5 grams protein.
- Hard-boiled egg (1 egg): 0.5 grams net carbs, 5 grams fat, 6 grams protein.
- Sugar-free beef jerky (1 oz): 0.5 grams net carbs, <1 gram fat, 6 grams protein
- Nitrate-free deli meat (1 oz): 1 gram net carbs, <1 gram fat, 5 grams protein.
- Full-fat laughing cow cheese (1 wedge): 1 gram net carbs, 4 grams fat, 2 grams protein
- Brazil nuts (6 nuts): 1 gram net carbs, 10 grams fat, 1 gram protein
- Macadamia nuts (1 oz): 2 grams net carbs, 21 grams fat, 2 grams protein
- Almonds (1 oz): 3 grams net carbs, 14 grams fat, 6 grams protein
- Pecans (1 oz): 1 gram net carbs, 20 grams fat, 2 grams protein
- Walnuts (1 oz): 2 grams net carbs, 18 grams fat, 4 grams protein
- Celery (1 cup): 1 gram net carbs, 0 grams fat, <1 gram protein
- Olives (1 oz): 1 gram net carbs, 3 grams fat, <1 gram protein
- Seaweed snacks (½ pack): 0-1 gram net carbs, 3 grams fat, 1 gram protein
- Avocados (½ avocado): 2 grams net carbs, 14 grams fat, 2 grams protein
- Cucumber (1 cup): 4 grams net carbs, 0 grams fat, 0 grams protein
- Zucchini (1 cup): 3 grams net carbs, 0 grams fat, 1.5 grams protein
- Broccoli (1 cup): 4 grams net carbs, 0 grams fat, 2 grams protein
- Cauliflower (1 cup): 3 grams net carbs, 0 grams fat, 2 grams protein
- Green pepper (1 cup): 4 grams net carbs, 0 grams fat, 1 gram protein
- Raspberries (1 cup): 6 grams net carbs, <1 gram fat, 1 gram protein
- Blackberries (1 cup): 6 grams net carbs, <1 gram fat, 1 gram protein
Foods to Avoid on the Keto Diet
You’ll also want to know which foods to steer clear of if you want to hit your keto goals. Here’s a list of high-carb foods to avoid on the keto diet:
- Grains and starches like oats, corn, quinoa, flour and rice
- Root vegetables like potatoes, beets and turnips
- Grain products like cereals, bread, pasta, granola, muesli and crackers
- Legumes like beans, peas and lentils
- Sweeteners like cane sugar, honey, maple syrup and corn syrup
- Sweetened drinks
- Sweetened sauces and dips like ketchup, barbecue sauce and some salad dressings
- Assorted higher-carb fruits
Please Note: Some of the above foods are commonly found in healthy, well-balanced diets. So, their inclusion on this list is not a knock on them. However, they are not ideal for the keto diet due to their unique macronutrient profiles.
Is the Keto Flu a Real Thing?
Well, yes and no.
The keto flu is not the actual flu. It’s simply a series of flu-like symptoms that may or may not occur as your body adapts to the diet’s strict parameters. When you decrease your carbohydrate intake, your body releases sodium, potassium and water, which can potentially lead to dehydration.
Potential symptoms include nausea, fatigue, headache, vomiting and general weakness. Keto flu symptoms typically subside once the body reaches a state of nutritional ketosis, which takes anywhere from a few days to a couple of weeks.
Proper hydration and consuming key electrolytes, like sodium, magnesium and potassium, can help reduce these symptoms. Spinach, hemp seeds, avocado, salmon, cashews, Brussel sprouts, mushrooms and zucchini are examples of electrolyte-rich, keto-friendly foods.
What is the Dirty Keto Diet, and is it Safe?
The dirty keto diet is a popular variation of the keto diet. It follows the same macronutrient guidelines but allows for lower-quality ingredients, fast foods and processed foods — thus the “dirty” part.
While you may achieve some of the same benefits on the dirty keto diet, you’ll also incur additional risk, as the regular consumption of processed foods can lead to a series of side effects, including heart disease, high blood pressure and high cholesterol.