The high-fat, very low-carb keto diet lets you enjoy lots of avocado, butter, bacon and cream—but requires cutting way back on added sugars, most processed foods, sweets, grains, and starchy veggies (whew). The eating plan is mega-popular among Hollywood A-listers (including Halle Berry, Megan Fox, and Gwyneth Paltrow); but if you don’t have a private chef who can futz with fats to make delicious meals and snacks, the carb-restricted lifestyle can be extremely challenging to follow.

Thankfully, a few keto variations have been developed that are a little more flexible, and easier to stick with long-term. The traditional or standard ketogenic diet puts your body into ketosis: In this metabolic state, you burn fat (rather than carbs) as your primary fuel source, and that promotes fat loss. On a modified keto diet, your body will go in an out of ketosis, but still shed weight and body fat. Check out the guide below to see how each of the four keto diet types work.

Standard ketogenic diet (SKD)

Macronutrient ratio: 75% fat,15-20% protein, 5-10% carbs

On the standard keto diet, you plan all meals and snacks around fat like avocados, butter, ghee, fatty fish and meats, olives and olive oil. You need to get about 150 grams a day of fat (the amount in nearly ¾ cup of olive oil and three times what you are likely eating now) in order to shift your metabolism so it burns fat as fuel. At the same time, you need to slash your carbs from about 300+ grams per day to no more than 50 (which is about the amount found in just one blueberry muffin). That means sticking to leafy greens, non-starchy veggies, and low-carb fruits like berries and melon. Finally, you'll eat a moderate about of protein, which is about 90 grams per day or 30 grams at each meal (think 4 ounces of meat, fish, or poultry).

Targeted keto diet (TKD)

Macronutrient ratio: 65-70% fat, 20% protein, 10-15% carbs

The targeted keto diet is popular among athletes and active individuals who live a keto lifestyle but need more carbs. It allots an additional 20-30 grams of carbs immediately before and after workouts to allow for higher-intensity exercise and enhanced recovery. (The total carb count comes to 70-80 grams per day.) The best options include fruit, dairy or grain-based foods, or sports nutrition products. Because the additional carbs are readily burned off, they don't get stored as body fat.

Cyclical keto diet (CKD)

Macronutrient ratio: 75% fat, 15-20% protein, 5-10% carbs on keto days; 25% fat, 25% protein and 50% carbs on off days.

Keto cycling is a way to cycle in and out of ketosis while enjoying a more balanced diet on your "days off." One keto cycling approach includes five days of traditional keto diet and two non-keto days per week. Some people choose to save their off days for special occasions holidays, birthdays, and vacations. For best results, eat wholesome carbohydrate-rich foods on your off days, including fruits, starchy veggies, dairy products, and whole grains (rather than added sugars or highly-processed fare).

High-Protein Keto Diet (HPKD)

Macronutrient ratio: 60-65% fat, 30% protein, 5-10% carb

This plan entails eating about 120 grams of protein per day (or four 4-ounce servings of meat, fish or poultry) and around 130 grams of fat per day. Carbs are still restricted to less than 10% of daily calories. But many people find this modified keto diet easier to follow, because it allows you to eat more protein and less fat than the standard keto diet. The caveat is that this approach may not result in ketosis, because like carbs, protein can be converted into glucose for fuel. But the high-protein keto diet will generally result in weight loss.

One final note: Keep in mind that the jury is still out on whether or not the traditional keto diet—of any of its popular adaptations—is a preferred way to lose or maintain a healthy weight. Before you decide to give it a go, these are a few of the side effects and complications linked to the diet.