The concept

The plan involves fasting completely for 72 hours, then eating only meat afterward, and repeating that pattern. It combines prolonged fasting with an all-meat diet, both of which have strong metabolic effects and potential health risks when done repeatedly.

What happens during a 72-hour fast

After about three days without food, the body shifts from using glucose as its main energy source to using stored fat and ketones. Insulin levels drop, glycogen stores deplete, and the body begins breaking down some muscle protein to produce glucose for tissues that still need it.
People who complete 72-hour fasts often notice reduced appetite afterward and clearer thinking, but also lower energy and decreased physical strength. Studies on fasting show short-term benefits like improved insulin sensitivity and lower inflammation markers, yet they also show increases in stress hormones and potential loss of lean mass. The longer the fast, the greater the muscle loss risk if recovery nutrition and training are not carefully planned.

Hormones and metabolism

Extended fasting lowers active thyroid hormone (T3) and increases its inactive form (reverse T3). This is part of the body’s energy-saving response. For most healthy people, levels normalize after eating again, but doing long fasts frequently can keep thyroid function suppressed for longer periods. In people with high stress, low body fat, or irregular eating patterns, that can cause fatigue, cold intolerance, or reduced reproductive hormones.

The problem with refeeding

After 72 hours of fasting, the body is in a delicate metabolic state. Reintroducing food too quickly—especially if it’s high in protein and low in electrolytes—can create imbalances. The most serious version of this is called refeeding syndrome, where phosphate, potassium, and magnesium levels drop sharply as metabolism restarts. Even in milder forms, this can cause muscle weakness, heart palpitations, or swelling.
Safe refeeding usually means starting with smaller meals, gradually increasing calories, and including sources of carbohydrates, potassium, and magnesium to restore balance.

The issue with meat-only refeeds

A meat-only diet provides complete protein and essential fats but lacks fiber, vitamin C, magnesium, potassium, and several other micronutrients found in plants. Over time, that can lead to constipation, electrolyte issues, and possible increases in LDL cholesterol and uric acid.
High protein intake after fasting helps preserve muscle, but without balancing electrolytes and carbohydrates, recovery can be incomplete. There’s also no evidence that eating only meat after fasting improves results compared to balanced refeeds; in fact, it may increase strain on the kidneys in sensitive individuals.

Would repeating this cycle be healthy?

Doing this pattern once or twice under supervision might not be dangerous for a healthy adult, but repeating it long-term would likely cause problems. The combined stress of prolonged fasting, low nutrient intake, and high protein load can lead to:

• Loss of lean muscle tissue
• Hormonal disruption, especially thyroid and reproductive hormones
• Low energy, dizziness, or heart rhythm changes from electrolyte depletion
• Increased LDL cholesterol and uric acid levels in some people
• Digestive discomfort from zero fiber intake

A safer approach

If the goal is metabolic reset or fat loss, shorter and more balanced methods are safer and often more effective:

1. Use time-restricted eating (such as 16-8 or 20-4) instead of 72-hour fasts.
2. Break fasts with mixed meals—protein, vegetables, and some carbohydrates.
3. Stay hydrated with electrolytes throughout fasting.
4. Include resistance training to maintain muscle mass.
5. Track energy, sleep, mood, and lab markers to avoid over-restriction.

The bottom line

A cycle of 72-hour fasts followed by meat-only refeeds is not a sustainable or generally healthy routine. It can create nutrient deficiencies, hormonal imbalance, and muscle loss over time. While fasting and high-protein meals can both have benefits, combining them in such extreme, repetitive form adds unnecessary risk without proven advantage.
A balanced, shorter fasting schedule with gradual refeeding and varied foods is far more likely to improve health safely.