The fasting-mimicking diet is an eating plan meant to mimic the effects of fasting while still allowing for nutrient intake. Instead of not eating, a person following the diet consumes less than usual for a few days to a week.
For example, a person might halve their usual calorie intake on the first day and then eat even fewer calories on the remaining days. There are no time restrictions around eating.
Though some evidence suggests that the fasting-mimicking diet may provide some health benefits, it’s not suitable for everyone. If you’re considering this eating plan, it’s best to talk with a registered dietitian or another qualified healthcare professional to determine if it’s safe for you.
This article discusses the fasting-mimicking diet, including how it works, its potential benefits, and other cautions to keep in mind.
What is the fasting-mimicking diet?
The fasting-mimicking diet is a very low calorie, low protein, low carbohydrate diet that people usually follow for a few days. However, differently from other types of fasting diets, there are no time restrictions around when you can eat.
People who follow the fasting-mimicking diet usually eat about 40–50%
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of their usual calorie intake on the first day of the diet, then reduce it to around 10–20% for the remaining days. The diet typically lasts 4 to 7 days and may be repeated.
The fasting-mimicking diet is designed to mimic the effects of a traditional fasting diet while providing some nutrient intake. During the diet, your nutrition primarily focuses on plant-based foods, such as:
- nuts
- seeds
- vegetables
- healthier fat sources like olive oil
What can you eat on the fasting mimicking diet?
The fasting-mimicking diet is based on
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very low protein and low carbohydrate foods and a high intake of healthy fats. The eating plan focuses on consuming foods that can provide appropriate support to your body while remaining nutritionally balanced.
Here are some foods you can eat on the fasting-mimicking diet:
- Nuts and seeds: Walnuts, almonds, chia seeds, and other types of nuts and seeds are good sources
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of fiber, minerals, and healthy fats. - Avocado: Avocados are rich in healthy monounsaturated fats that can help you feel full. These fats also have many health benefits, including
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helping your body burn fat and lowering blood pressure. - Leafy greens: Kale, spinach, Swiss chard, and other leafy greens can provide you
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with essential nutrients like fiber, minerals, and vitamins. - Fatty fish: Fish like salmon, sardines, and mackerel are rich in omega-3 fatty acids. These may reduce inflammation
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and promote heart health by reducing the risk of cardiovascular disease. - Berries: Blueberries, strawberries, and other types of berries are rich in antioxidants. These substances may help reduce
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inflammation and cell damage, potentially reducing the risk of developing several health conditions, including cancer.
If you have access to a registered dietitian, they can recommend a dietary plan based on the fasting-mimicking diet. It’s essential to ensure you get adequate nutrients to reduce the risk of developing any nutritional deficiencies over time.
Learn more about different fasting methods and how to fast safely.
What shouldn’t you eat on the fasting-mimicking diet?
People following the fasting-mimicking diet typically limit certain foods or food groups, including:
- Processed foods: This includes refined products and foods containing added sugars, such as chips, cookies, or sweets.
- Dairy products: This includes foods like milk, cheese, and yogurt.
- Animal protein: People on this diet generally avoid:
- eggs
- meat
- fish that are not rich in omega-3 fatty acids
- any other type of animal protein
- Fruits: This includes oranges, bananas, grapes, and other types of fruit apart from berries.
- Starchy vegetables: Starchy vegetables like potatoes, butternut squash, and turnips, are high in carbohydrates and unsuitable for the fasting-mimicking diet.
What are some potential benefits of the fasting-mimicking diet?
Some research indicates that the fasting-mimicking diet may provide
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several health benefits, including:
- reducing cholesterol levels
- promoting weight loss in people with overweight or obesity
- reducing systemic inflammation and cell damage
- lowering blood pressure
- lowering blood sugar levels
- slowing aging
- reduced risk of conditions such as:
It’s important to note that the fasting-mimicking diet has not been definitively proven to treat or prevent any health condition effectively. Also, some of the research has been done only on animals.
More human-based research is needed to determine the diet’s exact benefits and how it may fit into people’s lives on a broader scale.
If possible, always speak with a doctor or a registered dietitian before starting the fasting-mimicking diet or any new dietary regimen.
Learn more about the possible benefits and risks of fasting.
Are there any potential risks or other cautions with the fasting-mimicking diet?
The fasting-mimicking diet may not be safe for everyone. This includes children and people who have specific food allergies or nutritional deficiencies or who are pregnant.
Significantly reducing your calorie intake can lead
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to malnourishment, adverse changes in metabolism, and complications such as bone loss. Also, it can be easy to have an imbalanced diet when the focus is on calorie restriction but not diet quality — it’s essential to ensure the food you’re eating is rich in essential nutrients.
The fasting-mimicking diet also hasn’t been studied in the long term, so the long-term safety isn’t clear.
It’s also important to note that keeping close track of calorie intake may sometimes cause or worsen
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disordered eating behaviors. If you feel like an eating plan is adversely affecting your mental health or your relationship with food, seek help from a mental health professional.
If you’re preoccupied with food or your weight, feel guilt about food choices, or engage in restrictive diets, consider reaching out for support. These behaviors may indicate a disordered relationship with food or an eating disorder.
Disordered eating and eating disorders can affect anyone, regardless of gender identity, race, age, socioeconomic status, or other identities.
They can be caused by any combination of biological, social, cultural, and environmental factors — not just by exposure to diet culture.
Consider speaking with a healthcare professional or contacting the National Alliance for Eating Disorders, which offers a daytime helpline staffed by licensed therapists and an online search tool for treatment options.
For general mental health support, you can call the Substance Abuse and Mental Health Services Administration 24 hours a day at 1-800-662-4357 (or 1-800-487-4889 for TTY).
The fasting-mimicking diet, like any other eating plan, should be undertaken only with the help and supervision of a registered dietitian or other qualified healthcare professional.
The fasting-mimicking diet differs from traditional fasting plans in that it allows for some nutrient intake while placing no time restrictions around eating. It emphasizes the consumption of plant-based foods like nuts, seeds, and berries and fatty fish like salmon.
This eating plan may not be suitable for everyone. If possible, talk with a registered dietitian or doctor before trying the fasting-mimicking diet.