What Is the Special K Diet?

Special K diet

Verywell / Debbie Burkhoff 

At Verywell, we believe there is no one-size-fits-all approach to a healthy lifestyle. Successful eating plans need to be individualized and take the whole person into consideration. Prior to starting a new diet plan, consult with your health care provider or a registered dietitian, especially if you have an underlying health condition.

The premise of the Special K diet, sometimes also called the "K Diet," is simple. The diet is essentially a two-week challenge to consume Special K cereal as a meal replacement for two out of your three main meals each day with the promise of quick weight loss.

The Special K diet was developed as part of a marketing strategy by the cereal creator itself. In 2002, Kellogg’s funded a study with researchers from Purdue University to determine if consuming “ready-to-eat” cereal as a meal replacement twice a day would lead to weight loss. The study was published in the Journal of the American College of Nutrition with promising outcomes.

As a result, the Special K Challenge was marketed to the masses with a primary focus on women. The promise? Kellogg’s claims that the Special K Challenge is "a simple, great-tasting way to drop up to a jean size in just two weeks. The Challenge takes the guesswork out of weight loss by telling consumers to replace two meals with a Special K Cereal or Meal Replacement Bar followed by a reasonable, healthy third meal.”

The Special K Challenge was a popular diet option for almost a decade, as it seemed like a viable way to lose weight quickly. For this reason, it appealed to many people.

However, in 2013, Special K sales—along with the sales of many other "weight loss foods"— began to decline. Americans were losing interest in eating diet foods and began shifting their focus to choosing healthy food options. Since then, Kellogg’s has altered its marketing of the cereal.

However, the premise of the diet—along with all its limitations—still exists. Additionally, the Special K diet has evolved over time to include more branded products as meal and snack replacements.

Although it’s only followed for 14 days, eating the same cereal for two meals per day restricts you from consuming a variety of foods and benefiting from a variety of nutrients. Additionally, the diet doesn't establish eating patterns beyond the two-week period, so most people are likely to resort to their usual eating habits once the challenge is complete.

What Experts Say

"The Special K Diet encourages replacing meals with cereals and bars to promote weight loss—up to 6 pounds in two weeks. The health community warns that this is unsustainable. Plus, most Special K products are low in satiating fat and protein, so you may feel hungry."

Chrissy Carroll, RD, MPH

What Can You Eat?

The essence of the Special K Diet is that it’s a portion-controlled, two-week challenge that recommends substituting two meals per day with Special K cereal. In addition, the diet allows for portion-controlled snacks, vegetables, and fruits to support short-term weight loss or weight maintenance goals.   

The diet was never intended or marketed as a long-term weight loss solution, but instead, as a jumpstart option to help you meet an initial weight loss goal.

The Special K diet is simpler and has fewer rules than many other weight loss programs. Originally comprised of just Special K breakfast cereal and fruit, the diet has evolved since 2003 to include shakes, meal bars, cracker chips, and popcorn chips. Many Special K products are made from lightly toasted rice, wheat, and barley. You can expect to eat:

  • 1 cup of Special K cereal with 1/2 to 2/3 a cup of skim milk for breakfast and lunch. A protein meal bar or protein shake can be substituted for lunch.
  • Fruits, vegetables, and other Special K food options, such as protein or granola bars, protein or breakfast shakes, crackers, cracker chips, or popcorn, should be enjoyed as snacks.
  • No restrictions are placed on the third meal of the day.

What You Need to Know

The structure of the Special K diet is simple to understand and implement. There are no set times for meals or snacks—you can enjoy them as they fit your schedule. The following is a sample meal plan on the Special K diet.

Breakfast (Meal 1)

  • 30 grams (about 1 cup) Kellogg’s Special K Cereal
  • 2/3 cup skim milk
  • 1 medium banana


  • Kellogg’s Special K Red Berries Chewy Snack Bar

Lunch (Meal 2)

  • Kellogg’s Special K Red Berries Chewy Snack Bar
  • 30 grams (about 1 cup) Kellogg’s Special K Cereal
  • 2/3 cup skim milk
  • 2 cups salad


  • Kellogg’s Special K Chocolatey Dipped Mint Protein Meal Bars
  • 1 medium apple

Dinner (Meal 3)

Suggested Products

The Special K diet doesn’t have specific recipes you need to follow, but the following Kellogg's Special K products, cereals, bars, treats, and shakes are suggested to replace meals and snacks.


  • Special K Blueberry with Lemon Clusters
  • Special K Fruit & Yogurt
  • Special K Vanilla Almond
  • Special K Apple Cinnamon Crunch
  • Special K Probiotics Berries & Peaches
  • Special K Protein Honey Almond Ancient Grain

Frozen Meals

  • Special K Portabella, Kale & Quinoa Quiche
  • Special K Sausage, Pepper & Cheese Quiche
  • Special K Spinach, Egg & Cheese Medley Flatbread Breakfast Sandwich
  • Special K Bacon, Egg & Cheese Medley Flatbread Breakfast Sandwich

Bars & Bites

  • Special K Nourish Cranberry Almond Chewy Nut Bar
  • Special K Nourish Blueberry Almond Quinoa Bites
  • Special K Nourish Chocolate Almond Chewy Nut Bar
  • Special K Nourish Dark Chocolate Pistachio Bites

Treats and Shakes

  • Special K Cookies & Crème Pastry Crisps
  • Special K Brown Sugar Pastry Crisps
  • Special K Red Velvet Pastry Crisps
  • Special K Vanilla Cappuccino Protein Shakes
  • Special K Chocolate Mocha Protein Shakes
  • Special K Milk Chocolate Protein Shakes

Pros and Cons 

  • Special K products are cost-efficient

  • Practical diet—not much planning required

  • Relatively safe and no associated health risks if followed for two weeks or less

  • May cause increased appetite

  • Limited options can be boring

  • Short-term plan

  • Doesn't create healthy habits

The Special K diet may seem like a simple way to lose weight, but the restrictive eating plan has its drawbacks. Review the pros and cons to inform your decision about whether this diet is right for you.



While many diets require specific powders, supplements, and/or expensive ingredients, Special K products are reasonably priced. An 11.2-ounce box of Special K retails for less than $5.


The Special K diet takes the guesswork out of what to eat at meals. You simply swap out two meals per day with a portion-controlled bowl of cereal. You'll spend less time and money planning and preparing meals. Special K cereals and other products are familiar to most people and can be easily found at your local grocery store.


The Special K diet doesn’t require you to go vast periods of time without eating or to eat questionable supplements or products. It’s a relatively safe diet to follow for the short-term only.

Due to its limited choices and because Special K products are low in fiber and protein, the Special K diet is not considered a nutritionally balanced long-term eating solution.


Increased Appetite

There is a potential for increased appetite for those following the Special K diet. In the 2002 study, the two groups who consumed Kellogg’s cereal at two meals each day reported increased hunger versus the baseline groups.


Another drawback you may experience is boredom—eating the same foods over and over again each day can be quite mundane.


The Special K diet is also not a long-term solution—it's marketed as a short term solution to follow for two weeks only. It also provides limited nutrients. Eating the same foods over and over can limit the overall amount and variety of nutrients you consume.

Doesn't Create Healthy Habits

By following a short-term diet or challenge with specific meal replacement products, you’re not establishing good-for-you habits or learning how to incorporate healthy, real foods into your diet for the long-term.

Is the Special K Diet a Healthy Choice for You?

The Special K diet is similar to other meal replacement diets such as SlimFast or Nutrisystem in which at least one, if not all meals throughout the day, are replaced with a specific, branded food product. What the diets offer, however, doesn't meet all optimal nutrition recommendations.

The United States Department of Agriculture (USDA) shares guidance for improving and maintaining overall health and well-being. These dietary recommendations include calorie guidance and tips for a healthy, balanced diet. The Special K diet meets some of the criteria, but not all.

The Special K Diet, like the other meal replacement diets, places some control on the foods you eat and manages overall portions. These meal replacement diets primarily work by limiting the overall daily calorie intake.

For instance, in the 2002 study, Purdue University researchers found that the two different groups eating cereal for two meals per day reduced their overall calorie intake by an average of at least 600 calories per day.

Taking in fewer calories than you use each day can help you achieve your weight loss goals, but you should limit calories in a healthy and balanced way. Use this calorie calculator to determine your daily intake to meet your weight loss goals.

While the other meal replacement diets provide a variety of healthy foods and focus more on controlled portions, the Special K Diet relies primarily on Special K cereals, which limits the variety of food and nutrients recommended by the USDA. This is likely why the diet is only recommended for two weeks.

Health Benefits

While proponents of the Special K diet claim that it's a quick, cost-effective way to lose weight, the restrictive nature of this eating plan is not supported by health and nutrition experts. On the plus side, however, the diet is low in saturated fat, cholesterol, and sodium.

Special K cereal is a good source of vitamins A and D and an excellent source of vitamin C, iron, thiamin, riboflavin, niacin, folic acid, and vitamins B12 and B6, and can be consumed as part of a healthy, well-balanced diet.

Health Risks

Though there are no common risks associated with a short-term Special K diet, this eating plan restricts food groups containing important nutrients. Special K cereals are not typically made with whole grains. Therefore, they’re low in fiber (foods higher in fiber can help you feel more full after eating them). One cup of Special K Red Berries cereal has just 2.6 grams of fiber or about 10% of the daily value. The cereal is also low in satiating protein, providing just 2 grams per one-cup serving.

The results of this were evident in previous studies which reported increased appetite while consuming the ready-to-eat cereal for two meals per day. The cereal is also low in potassium but the diet recommends eating fruits and vegetables with the meals and as snacks, which are high in potassium.

Similar Diets

Here’s how the Special K Diet compares to some of the other more popular meal replacement programs.

The Special K Diet

  • Accessibility: No delivery required—purchase products at your local grocery store.
  • Cost: A box of cereal retails for about $2 to $3. A box of Special K bars costs about the same.
  • Types of food: Two meals per day are replaced with ready-to-eat cereal and skim milk.
  • Diet duration: The Special K diet is also only marketed for two weeks.
  • Diet balance: The Special K diet is restrictive, lacking in protein, fiber, healthy carbs, and healthy fats. Because of its restrictive nature, its only recommended the diet is followed for two weeks.


  • Accessibility: No delivery required—purchase products at your local grocery store.
  • Cost: An 11-ounce container of SlimFast protein powder retails for $12.99.
  • Types of food: The premise of the SlimFast diet is similar to the Special K Diet. The SlimFast diet includes replacing two meals per day with SlimFast shakes, bars, or cookies and enjoying 100-calorie snacks in between meals.
  • Diet duration: Unlike the Special K diet, there is no recommended duration for the SlimFast diet.
  • Diet balance: The SlimFast diet is more balanced and less restrictive than the Special K diet. The SlimFast shakes are higher in filling fiber and protein compared to Special K cereals, providing 5 grams and 20 grams respectively. They’re also fortified with nutrients—they’re an excellent source of vitamins A, C, D, E, and K as well as calcium and iron. The diet isn’t unsafe, but it’s not centered on eating whole, real foods.


  • Accessibility: The Nutrisystem meals must be ordered online from the company.
  • Cost: The Nutrisystem diet requires more commitment up front compared to the Special K or SlimFast diets. Purchasing a one-time delivery four-week meal plan costs between $438.45 and $607.68 depending on the selected plan.
  • Types of food: Six mini-meals each day comprised of real food (for instance, waffles with scrambled eggs and coffee, low-fat string cheese with carrot sticks, and grilled chicken sandwich with a side salad).
  • Diet duration: Unlike the Special K diet, there is no recommended duration for the Nutrisystem plan.
  • Diet balance: The Nutrisystem diet is made up of many whole foods and is not as restrictive as the other diets because it offers a variety of portion-controlled foods.

A Word From Verywell 

While the Special K diet promises losing up to six pounds in just two weeks, the diet was only popular for about 10 years before sales of the products began to decline. The diet itself is not necessarily dangerous, but it doesn’t promote healthy or sustainable eating habits and is not viewed as a long-term weight loss solution by experts.

Following a regimented or highly restrictive diet with the goal of losing weight is not always the resolution for healthy weight loss or the answer to all of your health goals. Many factors like exercise, sleep, meditation, and more play a major role in your overall health. Aim to eat a balanced healthy diet that fits your lifestyle.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, and budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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