There are two main types of fasts: clean and dirty. Both have their pros and cons, and depending on your goals and lifestyle, one may be better for you than the other. This article discusses the differences between clean and dirty intermittent fasting and which one may be best for you.
What is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and feeding. There are different methods that you can use for intermittent fasting. Some people fast for 16 hours and eat in an eight-hour window, while others like to fast for five days a week and fast for two days. It really depends on your lifestyle and current schedule. Check out more about fasting and fasting methods in our other post.
Intermittent fasting has become increasingly popular in recent years due to its health benefits and ability to help people lose weight. The two main types of fasting are clean and dirty intermittent fasting.
What is Clean Fasting?
The name ‘clean fast’ may trigger thoughts of clean eating. However, when it comes to IF, the word ‘clean’ refers to sticking to the traditional rules of this restrictive diet.
A clean fast only allows calorie-free beverages like water, unflavored sparkling water, black coffee, and unflavored tea during the fasting window. Although black coffee contains approximately 5 calories per cup, there aren’t enough calories to break the fast. However, it would be different if you added sugar, cream, or milk as it would turn it into a dirty fast. We’ll talk more about dirty fasting in a moment. Let’s first discuss clean fast characteristics.
During the clean fast, here’s a list of foods and drinks you should avoid during the fasting window:
- Products that are artificially or naturally sweetened, such as beverages, water additives, gum, mints, and breath sprays.
- Flavored coffee.
- Sweet or fruity flavors. This includes anything that may be marketed as “zero-calorie” or “doesn’t raise blood glucose” or “low glycemic.”
- Protein-containing supplements such as BCAAs
- Bone broth
By avoiding these products, you are preventing your body from releasing insulin. This will help your body access stored body fat more efficiently. Your body will also undergo ketosis and autophagy. Ketosis refers to when your body enters a metabolic state where it starts to burn body fat and ketones for energy instead of stored glycogen. On the other hand, autophagy is when the body can use and reuse old and damaged cells. This helps the body cleanse itself from these damaged cells and start making space for new ones.
Considering that our goal is to generate optimum conditions for fat-burning and autophagy, we don’t want to consume anything that might disrupt these processes.
What disrupts ketosis and autophagy?
Here are the factors that disrupt ketosis and autophagy:
Insulin is a hormone that pushes sugars (glucose) that comes from digestion into body tissues and organs like muscles and the liver. Thanks to this process, our body has easily accessible energy. However, this means that our body needs to work through these sugars first before it can start tapping into our fat stores for energy.
It can significantly affect your ability to shed fat, especially if your diet is high in carbohydrates. Therefore, we should limit any foods or drinks that contain carbohydrates and raise our blood sugar levels.
Some protein-rich foods can also cause the body to release insulin and stop autophagy. This includes protein shakes and BCAAs.
When our body has too much protein, it can convert it into glucose during digestion. This process is called gluconeogenesis.
Now that you know the purpose of fasting, you have a better idea of why it’s important to avoid eating or drinking certain products.
What is Dirty Fasting?
Dirty fasting is just the opposite of clean fasting.
If you think about it, fasting means going without food or not consuming any calories. Some suggest that time-restricted eating and other diets are redefining what it means to be in a state of physiologic or molecular fasting. Therefore, if the food or drinks you consume do not make the body respond the way it would when eating normally, then dirty fasting may still be considered a form of “fasting.”
Fasting for weight loss can limit your carbohydrate and sugar intake, reducing your insulin levels. As a result, hormones such as glucagon and epinephrine rise. Fat tissue cells release stored fat in response to these hormones.
In some cases, some of the fat in our food travels to the liver, where it’s converted to ketones. The ketones are then sent back into the blood. When ketones are present in the body, they replace glucose as the brain’s main source of fuel.
People can achieve physiological fasting even with the limited caloric intake permitted by a dirty fast if glucose and insulin levels remain low.
What can you consume on a dirty fast?
Here is a list of foods you can consume during a dirty fasting window:
- Artificial sweeteners like aspartame, Splenda, and stevia
- Cream, 2% cow’s milk, and almond milk
- Honey and maple syrup
- Bone broth
If you want to try dirty fasting, add them to beverages for flavor.
Notably, you cannot consume as much of these products as you wish. This would make the goals of fasting obsolete. Therefore, ensure that your dirty indulgences remain below 50 calories. This number of calories is negligible, and the body will not respond with insulin.
Which is better — Clean or Dirty Fasting?
The truth is, if you stick to the rules of dirty fasting and ensure that your calorie intake in your fasted state remains below 50 calories, you are still going to benefit from intermittent fasting. However, some of these products like artificial sweeteners are not necessarily healthy. For example, some people report having an upset stomach, bloating, and gas after consuming some of these products. On the other hand, some report higher blood pressure and mood swings. If you consume these types of products on an empty stomach, experiencing these side effects is likely.
Furthermore, if you miscalculate the calories you’re consuming in your fasted state, you could also break your fast. By consuming calories during your fasting state, you are walking on thin ice. So, unless you feel comfortable with your food and calorie tracking, you should stick with clean fasting.
Can dirty fasting be a reason you’re not losing weight?
Your ability to lose weight depends on your health, hormones, and metabolism. All these factors are affected by your lifestyle, especially your diet.
Dirty fasting can hamper your weight loss progress if you consume too many calories during your fasting period. You can get kicked out of your fasting state if you overconsume calories. However, if you consume calories in moderation and remain under the 50-calorie mark, you will be absolutely fine.
Therefore, if you cannot live without your milk in coffee, don’t worry, have a tablespoon in your cup if you want it. You will still be in a fasted state after consuming it.
Factors that affect weight loss while you’re fasting
Here are the factors that can affect your weight loss results while intermittent fasting:
Sleep is one of the most important factors for achieving weight loss results. Without enough sleep, your body won’t be able to perform at its best, and you won’t have the energy to stick with your diet or exercise routine. Research has shown that getting at least seven hours of sleep a night can help boost your metabolism, reduce cravings, and even improve your body’s ability to burn fat. 
Additionally, not getting enough sleep can also lead to increased levels of cortisol — a stress hormone linked to weight gain. High cortisol levels can cause your body to store fat and make it harder to lose weight.
If you’re having trouble sleeping, try these tips:
- Reduce caffeine intake late in the day
- Engage in regular exercise
- Create a relaxing bedtime routine that includes dimming the lights and listening to calming music and practice meditation or deep breathing exercises
These strategies can help you fall asleep faster and stay asleep longer, which in turn can help you reach your weight loss goals.
Stress has long been associated with weight gain and difficulty in losing weight. It is important to understand how stress can impact your weight loss efforts, as it can ultimately affect your success.
Stress hormones like cortisol play a role in increased appetite and the development of fat around your midsection. When the body is under high levels of stress, it triggers cortisol release. This hormone encourages fat storage, especially around the abdomen, as well as increases cravings for unhealthy foods. Not only does this hinder weight loss progress, but it also has long-term health implications.
In addition to increased appetite and fat storage, chronic stress can lead to low energy levels. Without enough energy, it is difficult to exercise regularly and stick to a healthy diet. On top of that, poor sleep habits are often associated with stress, and inadequate sleep makes it even harder to have the energy needed for exercise.
Managing stress is an important part of achieving weight loss goals. Consider these stress management techniques:
- Breathing exercises
- Short walks
- Listening to calming music
- Talking to your friends and family
Medication can play a role in your weight success or failure. Certain medications can make it harder for you to lose weight, while others may help you reach your goals. Understanding how different medications may affect your weight loss efforts is key to achieving the best possible results.
Birth control pills are one example of a medication that can hurt your weight loss progress. This type of medication can lead to fluid retention and an increase in appetite, making it more difficult for you to reduce your calorie intake. Other medications such as glucocorticoids, thyroid hormone replacement therapy, and some antipsychotics can also hamper your weight loss journey.
On the flip side, some medications could help you with your weight loss efforts. These include diabetes medications, certain antidepressants, and appetite suppressants.
The main hormones that affect weight are leptin and ghrelin, which are produced by fat cells and stomach cells, respectively. Leptin signals to the brain when you have eaten enough, while ghrelin signals when you’re hungry. Imbalances in these hormones can lead to overeating or undereating, both of which can hinder weight loss progress.
Your body also produces cortisol, which is released during times of stress. High cortisol levels increase your appetite and cause cravings for high-calorie foods. Plus, it slows down your metabolism. This combination of effects can quickly lead to weight gain.
Finally, changes in thyroid hormones can also contribute to weight gain or difficulty losing weight. The thyroid produces hormones that regulate metabolism and when it isn’t functioning properly, your metabolism may be slower than usual.
If you’re having trouble losing weight, it’s important to assess the role hormones are playing. See your doctor if you suspect an imbalance, as they can provide advice on how to best manage your hormones for successful weight loss.
Age is one of the most surprising factors that can have a significant impact on weight loss results. It’s commonly known that as we age, our metabolisms slow down, which can make it harder to lose weight. It’s also been shown that our bodies tend to become less sensitive to hormones that regulate energy balance and fat metabolism as we age.
Aging can also cause changes in our muscle mass and bone density. As muscle mass decreases, our bodies become less efficient at burning calories, making it harder to keep weight off. Similarly, lower bone density can result in slower digestion, meaning fewer calories burned throughout the day.
Of course, there are still ways for older individuals to lose weight successfully, and this doesn’t mean that all hope is lost. Old timers can use dieting and exercise to achieve their desired weight loss results. Additionally, physical activity such as strength training can help preserve muscle mass and bone density, giving weight loss efforts an extra boost.
Is dirty fasting effective?
As long as you remain in the fasted state, dirty fasting will be as effective as clean fasting.
Is dirty fasting bad?
No, not necessarily. Consuming products deemed ‘unhealthy’ or ‘heavy’ but in moderation does not negatively affect your health. Overconsumption is what transforms dirty fasting into something negative.
Can you reach ketosis on dirty fasting?
Your body enters the state of ketosis when it doesn’t have enough carbohydrates to sustain itself. It then goes and scavenges for other energy sources, like ketones. So, as long as your ‘dirty foods’ come from sources with little carbohydrates, you can still reach the state of ketosis. Overall, your total carbohydrate intake per day needs to remain under 50 grams.
Intermittent fasting is a popular dietary pattern that involves cycling between periods of eating and fasting. Studies have suggested that intermittent fasting can have various health benefits, such as weight loss, improved blood sugar control, and reduced risk of certain chronic diseases. One debate that has been gaining traction in the health community is whether clean or dirty intermittent fasting is better for overall health.
Clean intermittent fasting refers to only eating or drinking calories during your eating window. On the other hand, dirty fasting refers to consuming products that provide no more than 50 calories during your fasting window.
Both clean and dirty fasting are considered effective fasting methods. Of course, both come with pros and cons. But it’s possible to reap the benefits of fasting no matter which method you choose.
- Papatriantafyllou E, Efthymiou D, Zoumbaneas E, Popescu CA, Vassilopoulou E. Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance. Nutrients. 2022 Apr 8;14(8):1549. doi: 10.3390/nu14081549. PMID: 35458110; PMCID: PMC9031614.
Article Updates Timeline:
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December 27, 2023
Dr. Rashmi Byakodi
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December 29, 2022