Fasting has been practiced for religious and spiritual purposes for millennia, but only recently has it come to the forefront because of the research suggesting some potential health benefits.
Those who have tried a true fast (stopping eating for a defined period of time) know that it can be mentally and physically challenging. Not to mention, it can be socially tricky. The fasting mimicking diet allows you to eat while still potentially experiencing some benefits of traditional fasting.
This article will explore the concept of a fasting mimicking diet and discuss the potential health benefits.
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What is The Fasting Mimicking Diet?
Fasting is often undertaken for weight management, wellness concerns, spiritual practices, or discipline. Fasting may support metabolic health, cardiovascular health, and overall well-being.
The complete restriction of calories for a defined period, as is required during a true fast, may be challenging for many of us. A fasting-mimicking diet is thought to offer some benefits of fasting without having to forego food intake altogether. A fasting mimic is performed by consuming fewer calories than usual in a specific ratio of carbohydrates, protein, and fat. This approach may help the body mimic a fasted state.
Emerging research also investigates mechanisms like autophagy that can be upregulated in a fasted state. Autophagy is the process of the body clearing out cellular debris and recycling cellular components. It is thought that autophagy helps manage cellular health.
How to Follow The Fasting Mimicking Diet?
A fasting mimicking diet is usually performed for five consecutive days per month. It can be repeated monthly or less frequently, depending on factors such as BMI and individual health goals. Specific foods that are low in calories, sugar, and protein but high in unsaturated fats are consumed during the fasting mimic.
The five-day period provides adequate time for the body to shift into a state of ketosis, promote autophagy, and potentially support health benefits. Once the five-day period is over, a regular diet is resumed.
On day 1 of the diet, approximately 1100 calories are consumed, consisting of 11% protein, 46% fat, and 43% carbohydrate. On days 2 through 5 of the diet, approximately 700 calories are consumed, consisting of 9% protein, 44% fat, and 47% carbohydrate.
Side Effects of a Fasting Mimicking Diet
Mild-to-moderate unpleasant side effects of a fasting mimic can occur in up to 46% of participants. The most common side effects are fatigue, weakness, headache, dry mouth, and memory impairment.
Research Backing The Fasting Mimicking Diet
Much research regarding the cellular mechanisms of how the fasting mimicking diet works has been performed in yeast, mice, and other animals. However, new research is emerging from human clinical trials suggesting that the fasting mimicking diet may support metabolic health and other wellness goals.
Metabolic Health
To date, the best evidence for the fasting mimicking diet is regarding metabolic health. Markers like blood sugar, hemoglobin A1c, BMI, lipid panels, and blood pressure have shown improvement in clinical studies.
A phase 2 clinical trial of 100 participants randomized to fasting mimicking diet or control diet demonstrated that markers associated with weight and body habitus (such as BMI and waist circumference) were significantly reduced compared to the control group. Remarkably, lean body mass was preserved in the fasting mimicking group (see more below).
Systolic blood pressure was also significantly lower in the fasting mimicking group. Of interest, patients who were at greater risk for health issues, for example, those with higher BMI, higher blood pressure, or unfavorable cholesterol panels, showed the most benefit from the three cycles of the fasting mimicking diet.
Results from another clinical trial using fasting mimicking diet intervention in patients with Type 2 diabetes showed significant improvements in hemoglobin A1c, fasting blood glucose, BMI, waist circumference, and blood lipids compared to the control group.
Kidney health is a serious concern for patients with type 2 diabetes and might also be supported with a fasting mimicking diet. A small proof-of-concept clinical trial evaluated 40 patients having both type 2 diabetes and kidney concerns (determined by an increased albumin-to-creatinine ratio). The patients who were in the fasting mimicking diet arm of the study and had baseline microalbuminuria experienced a significant improvement in their albumin-to-creatinine ratio at the end of the study.
Cancer
Cancer is another area being researched to evaluate possible effects of the fasting mimicking diet. A phase 2 clinical trial evaluated the blood marker insulin-like growth factor-1 (IGF-1) and its response to fasting mimicking diet. Elevated IGF-1 levels are associated with several cancers (colorectal, breast, prostate) and possibly associated with malignant melanoma, multiple myeloma, and thyroid cancer. The participants in the clinical trial who underwent three rounds of the fasting mimicking diet had significantly lower levels of IGF-1 compared to controls.
Many clinical trials are underway to evaluate the possibility of fasting mimicking diet enhancing cancer therapies. This topic is beyond the scope of this article but will be important to follow in the future.
Retention of Muscle Mass
A concern about fasting is the possibility of decreased muscle mass accompanying weight loss. A recent randomized study evaluated young men who underwent three cycles of a fasting mimicking diet compared to young men who ate standard diets. Despite a significant decrease in body mass in the participants who did the fasting mimicking diet, there was no appreciable difference in muscle force and muscle volume between the two groups at the end of the study.
Medical-Based Fasting Mimicking Diets
To date, the only commercially available fasting mimicking diet is Prolon by L-Nutra. This plant-based program provides the food necessary for 5-days. Vitamins, supplements, and herbal teas are also provided.
Before beginning a fasting mimicking diet, speak with your healthcare provider about your individual risks and benefits. Caution is advised for:
- Patients with food allergies (allergens in the Prolon program include soy and nuts, among others)
- Patients with type 2 diabetes or hypertension who are on medications that lower blood sugar or blood pressure
- Medications will likely need to be adjusted with the help of a healthcare provider during a fasting mimic
According to the Prolon website, certain populations should NOT participate in fasting mimicking diet. These include:
- Pregnant or breastfeeding women
- Children under age 18
- Adults over age 70
- Patients with an active or recurrent infection
- Patients with an eating disorder
- Patients who are underweight
- Patients who are malnourished or have a history of protein deficiency
Summary
Fasting has many potential health benefits but can be an arduous undertaking. The concept of being able to eat and still gain potential health benefits from a “fasting mimic” is appealing. A fasting mimicking diet has evidence for supporting many metabolic and cardiovascular risk factors, including blood sugar, insulin resistance, BMI, and blood pressure. Many clinical trials are ongoing to evaluate fasting mimicking diet as an adjunct to cancer therapies. Those at risk of specific cancers that are associated with elevated IGF-1 levels (like colorectal, breast, and prostate cancer) might find fasting mimicking diet beneficial. Much more human research is needed to evaluate the benefits of a fasting mimicking diet for longevity, autoimmune diseases, and other health conditions.
*Dr. DePorto has no financial affiliation with Prolon. She is receiving no monetary or product compensation for this article.
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