21-Day Keto Diet Meal Plan

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Written by Katelyn Johnson, Nutrition Science Expert and medically reviewed by Abby Courtenay

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People today are considerably more aware of the health hazards associated with being overweight. In addition to exercising, following a ketogenic diet can help you reduce weight naturally and learn to prepare meals with whole, healthy ingredients. There are also many benefits of this lifestyle that go beyond weight loss. 

Common wisdom says it takes 21 days to form a habit. The science behind that idea is not conclusive, but one thing’s for sure: eating keto for 3 weeks will give you a good idea of whether or not this type of lifestyle could work for you. 

It’s also enough time to get your body adapted to the eating style and achieve ketosis, which can improve physical health and mental performance. 

Once the three weeks are complete, you'll have the foundation you need to maintain the dietary regimen if you choose. 

So let’s learn more about what 21 ketogenic days will look like!

What is the 3-week keto diet meal plan?

Keto is a carb-restrictive, high-fat, moderate-protein eating plan that can assist you in achieving your health goals. This eating style helps your body to burn fat that has already been accumulated in your body.

Controlling macronutrients (carbs, fats, and proteins) is at the heart of the ketogenic diet. The most important thing to keep track of is carbs. Each person’s daily limit is different (calculate yours here), but most people need to keep their intake in the range of 20 to 50 grams of net carbs per day. The remainder of your diet is made up of healthy fats and protein.

Restricting carbohydrate intake induces a metabolic state known as nutritional ketosis. Carbs are the primary source of energy in the body, but when you follow keto, your body's energy demands are no longer met by carbs. So it turns to its stored fats for energy instead.

As the body’s primary fuel source is switched to fat, the ketosis state makes the body burn fat more efficiently, potentially resulting in greater weight loss. 

Furthermore, blood glucose levels are more consistent throughout the day, and many individuals report feeling more energized and having a reduced appetite, making it simpler to keep track of how much food you eat.

Who should try the keto diet?

The 21-day ketogenic meal plan can be utilized to help you lose weight. This is a low-carb diet that involves limiting carbs while increasing fat intake and maintaining a reasonable protein intake. However, it is not suitable for everyone. It can be used by the following people: 

  • People who have gained weight
  • Obese and overweight individuals
  • Individuals who are striving to improve their health and fitness
  • Those who desire to accelerate their weight loss efforts

However, everyone should speak with a doctor before trying this style of eating. Furthermore, it is not recommended for:

  • Children under the age of 18 (unless specifically prescribed by a doctor)
  • People with a history of disordered eating 
  • Individuals who are pregnant or breastfeeding
  • Those who are undergoing another treatment


Benefits of a 21-day ketogenic diet

The human body is remarkably adaptable when drastic changes are made to normal dietary consumption. When you limit carbs and eat enough fats, it will begin to produce and burn ketones as the main source of energy, inducing ketosis. 

Most people are able to enter ketosis in two to four days. So even if your body takes a bit longer than normal, 3 weeks of eating keto should give you plenty of time to start experiencing the health and weight-loss benefits keto is known for. 

Aside from the always appealing weight management benefits, changing dietary intake to a sustainable low-carb regimen optimizes cellular metabolism, boosts natural energy levels, and improves digestion. You may experience improvements in mood and appetite control, as well as increased mental clarity and focus.

Due to the enhanced satiety effects of proteins and lipids, weight reduction is partly a result of lower calorie intake. These foods take longer to digest and may help you control hunger and cravings. 

Following a keto diet can assist in lowering cholesterol, which is critical in lowering the risk of cardiovascular problems. It also aids in managing blood sugar levels, which may offer long-term benefits in regard to the treatment and prevention of type II diabetes.

Other possible ketogenic diet advantages, according to experts, include the prevention of some malignancies and neurological diseases including Alzheimer's and epilepsy.

Drawbacks of the 3-week keto diet

The diet's potential benefits are noteworthy, but there are a few drawbacks to be aware of. The ketogenic diet's ability to help people lose weight is undeniable. That said, the eating plan does not guarantee weight reduction. A carb-reduced diet demands discipline and consistency, which takes time because of how different it is compared to normal dietary habits.

It's also worth noting that there may be some adverse health effects that are very common to experience within the three weeks when you first start keto. 

For the first several days after lowering carbohydrates, you lose a lot of water weight, which can lead to dehydration. Those who begin the diet frequently experience what is referred to as the “keto flu,” which are flu-like symptoms that include, but are not limited to, headaches and lethargy. The flu-like symptoms may also worsen as a result of dehydration. To combat this, make an extra effort to drink water and consider supplementing your fluid intake with electrolyte tablets.

Kidney stones, nutrient deficiencies, and digestive irritation and/or irregularities are all possible complications. If you’re not careful, it can be easy to develop nutritional deficiencies when you eliminate and restrict certain food groups. To mitigate risks, your diet should be well-planned in order to cover your body’s fundamental nutritional requirements.

Tips to succeed on a 21-day keto diet plan

If you'd like to maximize the benefits of a keto, try the following suggestions:

  • Vary your meals during the 21-day diet and don't eat the same thing every day. It may dull you, and you will eventually dislike that food. As a result, make sure each meal is different. It also supports your taste senses and helps you stay on track with your weight loss goals. 
  • By varying the components, you may make your meals more interesting. Dieters can choose from thousands of dishes. You are free to use whichever meal plan you wish. However, keep an eye on your carbohydrate consumption. Do not take more than the recommended dose and consume lots of vegetables and healthy fats.
  • Make easy, wholesome meals that will not make you fatigued and will satisfy your hunger. Prepare ingredients ahead of time to make cooking more accessible and quicker. When following a recipe, make extra and freeze leftovers to eat later.
  • Increase the amount of raw and no-cook foods in your 3-week ketogenic diet. They'll give your diet some crunch and bite.
  • Don't overlook the necessity of carb restriction and be sure to supplement your regimen with high fat and moderate protein items.


How to hit keto macros 
The amount of calories, carbohydrates, proteins, and fats you need every day varies depending on your exercise level, body size, and other factors. Once you've figured out your personal macro amounts, you’ll keep track of what you eat to ensure that you stay within your goals.

It takes some time to get used to recording how many grams of each macronutrient are in your meals, but like anything, it becomes simpler with practice! Keep it up for 3 weeks and you’ll see that each day it gets a little bit easier.



Beginning the 21-day keto diet meal plan

A great way to make ketogenic eating easier is to prepare large quantities of foods or ingredients that you can take in different directions. 

Instead of buying just the drumsticks, buy the whole chicken, rub it with olive oil and spices, and pop it in the oven over a bed of vegetables like Brussels sprouts and red peppers. Eat one portion when it’s done cooking, then set aside the leftovers and store them in the fridge. Now you’ve got cooked chicken on hand to easily make:

  • Spinach salad with chicken, artichokes, feta, and olives
  • Lettuce-wrap chicken tacos with guacamole and salsa
  • Chicken soup with celery, carrots, and mushrooms

By making a large batch of homemade tomato sauce, you can quickly whip up things like:

  • Pizza with a cauliflower base and vegetable toppings 
  • Zucchini noodles with red sauce
  • Eggplant lasagna

Tomato sauce is a good example of something that’s easy to freeze and use later in weeks 2 and 3. 

As you can see, it’s best to plan out all 3 weeks of your ketogenic diet plan at the same time. That way, you can cook fewer dishes and spread them out over the 21 days.


Or why not go a tiny step further? We recommend that you start with a professional keto plan to create a solid foundation for your new low-carb lifestyle.


You can repeat many of the same meals to make food prep easier, but recipe diversity is also important. To get a variety of nutrients and avoid getting tired of certain ingredients or dishes, not every week should look the same.


Foods to eat on a keto diet meal plan for 21 days

List of keto-friendly foods:

  • Fats and oils, including butter, olive oil, sesame oil, almond oil, and flaxseed oil.
  • Dairy products such as cheese, sour cream, cream, and plain Greek yogurt.
  • Eggs.
  • Meat, especially chicken, beef, goat, and veal.
  • Fish, including trout, salmon, sardines, catfish, and tuna.
  • Nuts and seeds like walnuts, almonds, pumpkin, sunflower and sesame seeds.
  • Some fruits such as avocados, strawberries, and raspberries.
  • Low-carb veggies grown above ground like spinach, kale, zucchini, cucumber, broccoli, cauliflower, brussels sprouts, etc.

Non-ketogenic foods

  • Grains and starches, including wheat, corn, and rye.
  • Ultra processed foods. 
  • Sugary foods and drinks.
  • Specialized dietary products such as sugar-free, low-fat, etc.


Grocery list for a 3-week ketogenic meal plan

After you set up your chart of meals for 21 days, the next step is to write out a shopping list. Since you’ll want to incorporate fresh vegetables, meat, and seafood, it’s best to go to the store once a week.

Here is an example of ingredients you might include on your list:

Fruits and veggies

  • Lemons
  • Limes
  • Fresh or frozen blueberries, raspberries, strawberries
  • Cantaloupe
  • Spinach, arugula, kale
  • Tomato
  • Onion
  • Garlic
  • Artichoke
  • Bell peppers


  • Whole chicken
  • Pork chops
  • Steak
  • Organ meats
  • Fresh fish fillets, like salmon, trout, tilapia, cod
  • Seafood like shrimp, mussels, clams
  • Eggs
  • Tofu, seitan, tempeh


  • Cheese, like cheddar, edam, monterey jack, colby, mozzarella, gorgonzola
  • Butter
  • Cream
  • Almond or soy milk


  • Extra virgin olive oil
  • Herbs and spices, like organo, thyme, cilantro, paprika
  • Salt and pepper

Food that won’t go bad in 3 weeks

  • Canned tuna or sardines in olive oil
  • Walnuts, pistachios, peanuts, almonds
  • Sunflower seeds, chia seeds, flax seeds
  • All-natural nut butters
  • Pickles


Sample meals for the 21-day keto diet plan

Looking for recipe ideas? Here's a full day of ketogenic eating to get you started.

  • Breakfast: Smoked salmon roll-ups
  • Lunch: Kale salad
  • Snack: Celery and almond butter
  • Dinner: Healthy Caesar salad

Calories: 1,448 | Macros: 27 g net carbs, 95.5 g protein, and 109.1 g fat.


BREAKFAST Ingredients Serving Size Calories Net Carbs(g) Protein(g) Fat(g)
  Smoked salmon 100g 117 0 18.3 4.3
Smoked salmon roll-ups Avocado 1/2 avocado (101g) 161 1.8 2 14.8
Calories Net Carbs Protein Fat            
278 1.8g 20.3g 19.1g            
LUNCH Ingredients Serving Size Calories Net Carbs(g) Protein(g) Fat(g)
  Kale 3 cups (63g) 22 2.8 1.8 1.9
  Coconut oil 2 tablespoons (27.2g) 242 0 0 27
Kale salad Garlic (raw) 3 cloves (9g) 5 1.1 0.3 0
  Lemon juice from 1 lemon (48g) 11 3.2 0.2 0.2
  Soy sauce 2 tablespoons (36g) 22 2 3.8 0
  Cherry tomatoes 1/2 cup (74.5g) 13 2.9 0.7 0.1
  Red bell pepper 1/2 pepper (37g) 12 2.2 0.4 0.1
Calories Net Carbs Protein Fat            
327 14.2g 7.2g 29.2g            
EVENING SNACK Ingredients Serving Size Calories Net Carbs(g) Protein(g) Fat(g)
  Celery 2 medium stalks (80g)  11 1.1 0.6 0.1
Celery and almond butter Almond butter 2 tablespoons (32g) 197 6 6.7 17.8
Calories Net Carbs Protein Fat            
208 7.1 7.3 17.9            
DINNER Ingredients Serving Size Calories Net Carbs(g) Protein(g) Fat(g)
  Caesar salad dressing 1 tablespoon (14.7g) 80 0.4 0.3 8.5
Healthy Caesar salad Spinach, raw 3 cups (90g) 21 3.3 2.6 0.4
  Chicken breast 1 piece (174g) 275 0 55.9 5.6
  Olive oil 2 tablespoons (27g) 238 0 0 27
  Parmesan cheese 1 tablespoon (5g) 21 0.2 1.9 1.4
Calories Net Carbs Protein Fat            
635 3.9g 60.7g 42.9g            
DAILY TOTALS   1,448 cal 27g net carbs 95.5g protein 109.1g fat




21-day keto diet plan FAQ


Not exactly. Although most individuals can safely lose weight on the ketogenic diet, there’s no single plan that is right for everyone. Before beginning any diet, you should always consult with a medical expert.

Before starting a ketogenic diet, it is essential to speak with your doctor. This is especially true if you have certain health conditions, like diabetes (type 1 or type 2), high blood pressure, or both. Ketogenic diets are not recommended for pregnant or nursing women. Everyone should speak with a medical professional before changing their diet. 

In week 1, it’s possible to lose 2 to 10 pounds. In subsequent weeks, 1 or 2 pounds per week is the norm. So if you stick to ketogenic eating for 21 days, you  could potentially lose around 14 pounds.

That said, the amount of weight loss truly depends on each individual. Starting weight, exercise, age, gender, and how strictly you adhere to the diet are all contributing factors. 

Unfortunately, yes. The keto flu is one possible side effect of following keto. Your body is used to running on carbohydrates, so when it turns to fat burning, it takes time to adjust.

You may have less energy, and you could feel ill and lethargic, like you've had the flu. However, your body adapts to the dietary changes and will acclimate to this new manner of getting energy, which might take a few weeks.

Yes, in moderation, although it depends on which kind of alcohol. Check the carb count, especially for beers, which may vary widely. The lowest carb option is spirits, followed by wine.

The keto flu symptoms should have subsided by week three. Ideally, the gradual elimination of carbs and sugar has reduced these symptoms. You're likely to feel more confident in your ability to manage the plan altogether. Many people report being able to think more clearly, sleep more soundly, and have more energy by week three.


Similar keto meal plans 

Here are other options to explore when building new eating habits: