What is fasting?

Fasting means voluntarily abstaining from food (and sometimes beverages) for set periods—allowing the body to reset and repair. It holds deep significance across traditions, including Ramadan and Yom Kippur. Early societies naturally cycled through feast and famine, shaping human metabolism to alternate between glucose and fat for fuel; today’s constant food availability keeps nutrient-sensing pathways perpetually active.

The science: how your body transforms

• Fuel shift: once glycogen depletes, the body burns stored fat, producing ketones.
• Autophagy: after ~72 hours, fasting may activate the body’s self-cleaning process.
• Cellular rejuvenation: extended fasting promotes healthier cell repair.
• Metabolic flexibility: fasting supports insulin sensitivity and blood-sugar regulation.

“The Fasting Mimicking Diet helps the body bypass excessive muscle breakdown and shift into fat burning and ketone production—while still activating cellular rejuvenation benefits.” — Melanie Murphy Richter, MS, RDN

Types of fasting: finding your fit

Intermittent fasting: 16:8 or 12:12 time-restricted eating. 5:2 method: normal eating five days, reduced intake two days. Alternate-day fasting: alternating normal and very-low-calorie days. Water fasting: water only for 24+ hours (supervision needed for longer fasts). Prolonged fasting: 72+ hours for deeper changes. Fasting Mimicking Diet: five days of very-low-calorie plant-based meals that mimic water-fasting effects—three cycles support metabolic markers, sustained fat loss with muscle preservation, and may reduce biological age by 2.5 years.

The benefits

• Metabolic: enhanced insulin sensitivity and blood-sugar regulation.
• Cardiovascular: lowered blood pressure, triglycerides, and LDL cholesterol.
• Brain health: sharper cognition via ketones and autophagy.
• Healthy aging: autophagy and cellular rejuvenation linked to longevity.
• Gut health: digestive rest and microbiome support.
• Weight loss: sustainable loss, particularly abdominal fat.

Fasting safely

Proceed with caution (with supervision): people with diabetes, kidney/liver/cardiovascular conditions, those whose medications require food, and older adults. Not recommended: those with a history of eating disorders, pregnant or breastfeeding women, and children/adolescents. Always consult a medical professional before starting any fasting regimen.

Debunking common myths

Fasting slows metabolism? Strategic fasts like the FMD may improve metabolic flexibility. Fasting causes muscle loss? The FMD preserves lean muscle. Fasting leads to bingeing? Structured fasting typically helps regulate appetite. Fasting is only for weight loss? It also supports cellular repair, healthy aging, and brain health.

Prolon: a clinically tested pathway

Developed over decades by University of Southern California longevity researchers, Prolon’s 5-Day FMD keeps the body in a fasting state while unlocking cellular and metabolic benefits—autophagy and cellular rejuvenation beginning around Day 3, fat-focused weight loss with muscle preservation, and biological age reduction of up to 2.5 years with three consecutive monthly cycles.