In fitness and nutrition circles, the term clean has gained a specific meaning in recent years. No longer just a word used to describe a crisp, white T-shirt fresh out of the laundry, clean now refers to all manner of food items and diets.
Even specific eating patterns, such as the ketogenic diet, have come to be described using the terms clean and dirty. But what does it mean if you’re following a dirty keto diet versus a clean keto diet? And what’s the keto diet to begin with?
What Is the Keto Diet?
The ketogenic or keto diet is a strict eating pattern that seeks to severely limit the percentage of carbohydrates in the diet. While the keto diet is sometimes thought of as a high-protein diet, it’s actually a very high-fat, low-protein and very low-carb diet. The classic version of the diet is composed of 90% fat, 6% protein and just 4% carbohydrates, which forces the body to use fat as its primary source of energy. This triggers a biochemical process called ketosis.
Ketosis is when your body breaks down both dietary and stored fat for fuel and creates ketones in the process. Ketones are a byproduct of burning fat that are generated in the liver and can be measured in the blood. If you’re going to be strict about the keto diet, you’ll likely be testing your blood regularly to track the level of ketones to make sure you’re in the target zone for fat burning.
The ketogenic diet was originally developed in the 1920s to help control severe epilepsy in children. It’s still used to treat people who’ve not had success with other interventions, and more recently, it’s been suggested that the keto diet could help prevent the spread or recurrence of certain types of cancer. It can also help you drop weight quickly, and thus, some individuals are adopting this diet as a means of managing their weight.
What’s Clean or Dirty Keto?
If you’re following a clean keto diet, that means you’re avoiding processed foods, whereas a dirty keto diet is one that doesn’t focus as much on whole foods, but rather seeks to adhere only to the macronutrient ratio — that is, the ratio of fat, protein and carbs — of the diet.
“Dirty keto is a variation of the traditional keto diet and is sometimes referred to as ‘lazy keto,'” says Matthew Black, a registered dietitian with the Ohio State University Wexner Medical Center. Instead of consuming healthy fats, such as avocado and nuts, dirty keto opens the door to less healthy fats like those found in bacon, burgers and other highly processed foods.
“There aren’t clear guidelines for this variant, and it really depends on individual preference. The main difference with dirty keto (versus clean keto) is that users believe they can have more freedom to eat what they want, providing they maintain a low-enough carbohydrate intake,” Black explains.
Eating a dirty keto diet means there’s lots more room for restaurant food, takeout and processed foods, provided you stick with the macronutrient profile. The key with keto is hitting those macronutrient ratios to trigger ketosis. While it’s possible to stay in ketosis while following a “dirty keto” diet, it might be difficult to sustain.
The problem with prepared foods and other convenience items, says New York City-based registered dietitian Jamie Feit, of Jamie Feit Nutrition LLC, is that pre-made and ultra-processed foods tend to be high in sodium, calories and fat which promote inflammation and weight gain.”
For some people, dirty keto is relegated to so-called “cheat days” rather than being an all-the-time approach. “Some users of dirty keto will also allow occasional days of eating higher-carb foods, such as processed carbohydrates like chips, pretzels or baked goods,” Black says. “Additionally, dirty keto has less of an emphasis on the perceived quality of foods.” To some, this means certain foods that are a no-go on stricter or cleaner versions of the diet are in-bounds on the dirty version.
Dirty vs. Clean Keto Foods to Eat
Examples of foods that can be eaten on a dirty keto diet — regularly or only on cheat days — depending on your interpretation:
— Processed oils.
— Processed proteins.
— Low-carb snack foods, such as potato or tortilla chips and cookies.
— Chai and coffee drinks that contain coconut milk and sugar-free syrup.
— Pork rinds and beef jerky.
— Cheese chips.
— Salami and cheese.
For example, on a dirty keto protocol, you can eat a plain cheeseburger without the bun from any fast food restaurant, Black says. Though the food quality is low, it adheres to the macronutrient profile of the ketogenic diet.
By contrast, “clean keto is typically regarded as the original version of the ketogenic diet,” Black says. As such, this version places a higher emphasis on other elements, including:
— Healthy fats, such as avocado, olive oil and salmon.
— Nutrient density of foods.
— Overall food quality.
— Where foods were sourced.
— Avoidance of processed foods all together.
In keeping with the example above, someone on a clean keto protocol wouldn’t eat the fast food cheeseburger — even without the bun, Black says, but rather “would take issue with the beef not being from grass-fed cattle.” Instead, that person may opt for a leafy green salad with steak tips from grass-fed cattle.
Examples of Keto-Friendly Foods
|CLEAN KETO FOODS||DIRTY KETO FOODS|
|Baked chicken tenders with asparagus and butter||Brined and fried chicken tenders (minus the flour-based breading) with sugar-free BBQ sauce|
|Homemade zucchini chips fried in grass-fed ghee||Packaged keto-friendly cheese chips|
|Coconut milk and strawberry smoothie||Heavy cream and strawberry smoothie|
|Iced tea with stevia and bubbly water||Diet soda|
For some people, following a keto diet can lead to weight loss, which may lead to health benefits. “If an individual can tolerate staying on either (clean or dirty keto) diet long enough, weight loss could be the reward, which can lead to improvements in overall health ranging from lowering of blood pressure and decreasing insulin resistance,” Black says.
Studies are also ongoing into whether or not a ketogenic diet can slow the growth of cancer or reduce the risk of cancer recurrence. The idea is that many types of cancer cells thrive when growing in a high-sugar environment, so by depriving the body of sugar and forcing it to switch to a fat-burning mode of energy generation, that could slow down the growth of cancer or potentially shrink tumors.
There have also been some indications that the diet may be able to help with diabetes management, but long-term data is still limited and many doctors and nutritionists caution people with diabetes to proceed with caution and adopt a ketogenetic diet only under the guidance of a registered dietitian.
One 2016 study found that over the short term, the ketogenetic diet can cause gastrointestinal distress. “Common side effects include constipation from lack of fiber and long-term vitamin and mineral deficiencies from avoiding carbohydrate sources, which include fruits, many non-starchy vegetables, whole grains and dairy products,” says Hillary Adams, a clinical dietitian also with Providence Regional Medical Center Everett.
Another 2021 study found that the risks of the diet may outweigh the benefits, especially for pregnant women or those who are trying to become pregnant.
With both the clean and dirty versions of the keto diet, “the emphasis on high amounts of fat can lead to issues with hyperlipidemia, especially on dirty keto,” Black says. Hyperlipidemia is an increased concentration of fats and cholesterol in the blood, which can increase risk of heart disease.
In addition, cutting out major food groups such as fruits and vegetables can set you up for certain nutritional deficiencies, says Bromley Maharg, a clinical dietitian with Providence Regional Medical Center Everett in Washington state. So while losing weight could improve overall health for some people, that’s not the case for everyone, and eliminating nutrient-dense fruits and vegetables in favor of saturated fat may not be the healthiest move.
Black also notes that patients with liver or kidney diseases should not adopt a ketogenic diet because of “the role these organs play in digestion/metabolism of fat and proteins. Also, any patient who has tried either diet more than once but did not receive the desired results,” should probably skip it, he says, as it can lead to yo-yo dieting.
In addition, Adams notes, “people taking certain medications will experience negative side effects of following a ketogenic diet. Certain medications for improving blood sugar and A1C levels in those with Type 2 diabetes can experience extreme nausea and vomiting from consuming a diet so high in fat.” If you have diabetes or are on blood sugar-controlling medications, be sure to speak with your physician and a dietitian before adopting a keto diet.
Lastly, once your time on the strict eating regimen is over, don’t be shocked if the weight that fell off so quickly comes back just as fast, Maharg says. “Rapid weight loss often occurs once glucagon, a ketogenic hormone, is activated. This mobilizes fat stores for energy when carbohydrates (the body’s preferred source of energy) is not consumed. Despite rapid weight loss, weight gain results when you reintroduce carbohydrates and the body is no longer in ketosis.”
Adams notes that “further research is needed to determine the ultimate long-term health risks, as well as the effect on non-epileptic adults following the diet.” Currently, there’s not enough research to support the use of the ketogenic diet as a means of managing chronic illness outside of controlling intractable epilepsy. And she notes that “elimination of entire food groups can also lead to obsessive or disordered eating patterns.”
[Read: Keto Diet Dangers.]
Maharg notes that “following a true ketogenic diet can be expensive, as it relies on nutritional supplements to meet the generally high amounts of animal protein and fat, which are traditionally more expensive than alternative proteins such as beans, nuts and seeds.”
Plus, Adams says, “the ketogenic diet is often perceived as being very high in protein, not fat, which places further emphasis on higher consumption rates of meat, poultry and fish,” all of which can be expensive sources of calories.
This approach may not even have the desired results. “Consuming too much protein can prevent someone from achieving a ketogenic state,” Adams says.
Consuming prepackaged keto foods and products, while possibly more convenient and less time-consuming, can be very expensive, she adds.
Nevertheless, following a dirty keto could be cheaper than a clean version, Black says, “since it allows for processed foods. Clean keto demands for whole foods, nothing processed and more expensive protein sources, which is an acceptable notion, but will certainly increase your grocery bill.”
Which One Is Better?
So, is one version healthier than another? “In short, no,” Maharg says. “In order to achieve a state of ketosis, carbohydrate intake has to be minimal, as does protein intake. The prescribed diet recommends a ratio of 3 to 4 grams of fat for every 1 gram of carbohydrate and protein combined. High quantities of saturated fats are often required to meet this goal.”
But, consuming a high amount of saturated fats is linked to the development of cardiovascular disease.
Both diets follow similar prescriptions for the ratio of fat, carbs and protein, and for some people, the low-carb lifestyle can cause them to lose weight. However, because it’s very restrictive, either version of the diet is usually difficult to maintain long term. “The Achilles heel with both versions of the ketogenic diet is sustainability,” Black says.
Because there’s more wiggle room on the dirty version of keto, it may be slightly easier to maintain for a longer period. “While clean keto has higher standards, it still calls for high intakes of fats, such as coconut oil, which are far too high in saturated fat than recommended and can increase LDL cholesterol,” Black explains.
Keto advocates claim these oils will not cause issues with cholesterol, due to MCT oil content in coconut oil. But the average dieter will not always completely follow clean keto guidelines or know how to correctly implement them, he warns.
Ketogenetic diets, whether they’re clean or dirty, can lead to rapid weight loss, but maintaining that reduction long term can be really challenging.
“In general, any diet that requires users to make such drastic changes and all but eliminate the foods they enjoy, will typically offer limited long-term success,” Black says.
For this reason, “I do not recommend either to patients, unless there’s a clinical need, such as epilepsy,” Black says. “Otherwise, I find this diet to be only a temporary solution to a permanent problem. These diets attract users because they enable them to eat very indulgent and satiating foods,” because the fat content in them can make you feel fuller longer.
But the lack of variety gets old quickly. “In time, the average user grows weary of these diets and ultimately ends up returning back to the root cause of obesity,” Black says. These root causes include:
— Overconsumption of calories, often from processed carbohydrates.
— Lack of portion control.
— Poor understanding of human nutrition, which may be exacerbated by following fad diets.
Similarly, Maharg and Adams say they also “cannot safely recommend a ketogenic diet beyond the epileptic population. Instead, we emphasize inclusion of a variety within each of the five food groups: dairy, fruits, grains, protein and vegetables,” and they recommend meeting with a registered dietitian to find the right eating plan for your lifestyle and unique health needs.
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Update 05/24/22: This story was previously published at an earlier date and has been updated with new information.