Throughout evolution, fasting or food scarcity was a part of life. During this time, humans evolved natural mechanisms to protect the body during periods of famine that enhance the process of cellular repair.

Fast-forwarding to the current state of the science, clinical evidence proves that some forms of fasting can prolong life, help shed excess body fat, promote cellular clean up, and rejuvenate the body with stem cell-based regeneration.

Researchers have also studied the effects of calorie restriction on athletic performance. Restricting calories by 33% every other day has shown to lower heart rate and maximum oxygen consumption when performing the same exercises—without loss of lean body mass. Until recently, people did not realize a fasting diet could have health benefits beyond weight loss.

There are three types of fasting programs:

  • Prolonged Fasting: 4 or more days fasting with just water
  • Intermittent Fasting: 1–3 days fasting or alternate-day fasting
  • Time-restricted eating: limiting eating to an 8-hour period within 24 hours

The first diet mimicking fasting was developed by Dr. Valter Longo from the University of Southern California Center for Longevity. He is a biogerontologist and a cell biologist known for his clinical studies on the role of fasting and its effects on the cellular protection of aging, disease, and longevity.

According to his book, “The Longevity Diet,” fasting and caloric restriction help maintain cardiovascular and metabolic balance over time and help rejuvenate the body from the inside with stem-cell-based regeneration. Backed by 20 years of research, Dr. Longo developed a five-day meal plan in conjunction with a Mediterranean style diet that tricks the body into thinking it is fasting.

The “fasting” period only lasts five days a month for three months, resulting in weight loss, loss of visceral body fat (toxic fat that causes inflammation and contributes to diabetes), maintenance of lean body mass, lower blood pressure and blood sugar, improved cholesterol levels, and enhanced athletic performance. The food is plant-based without preservatives and includes nut bars, crackers, olives, and soups.

Most fasting diets, especially water fasts, do not help maintain lean body mass and deprive the body of micro and macronutrients. Dr. Longo’s diet includes supplements for micro and macronutrients. Backed by the National Institute of Health, it has the same health benefits of a five-day water fast—but with food. Look for improved energy, healthier lifestyle choices, and effects that persist after returning to a normal diet.

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Dr. Susan G. Murrmann is the co-founder of the McDonald + Murrmann Center for Wellness & Health.