The Hidden Dangers of Intermittent Fasting: What Happens During a 36-Hour Fast?

Intermittent fasting has become a popular diet trend worldwide, praised for its potential benefits in weight loss and metabolic health. But a recent simulation showing the body’s reaction to a 36-hour fast has many people questioning whether this method is as safe as it seems.

What Is Intermittent Fasting?

Unlike traditional diets that focus on what you eat, intermittent fasting is about when you eat. Common fasting patterns include the 16:8 method, alternate-day fasting, and extended fasts like the 36-hour fast. These methods aim to trigger fat burning by limiting the eating window and giving the body more time in a fasted state.

Viral Simulation Sparks Concern

A 55-second video by the Wellness Wise YouTube channel recently went viral for simulating the body’s response to a 36-hour fast. The video showed that even after just four hours of not eating, the body begins undergoing noticeable metabolic changes. As time progresses, fat is burned for energy—but not without side effects.

The shocking part? Many viewers were unaware of the potential health consequences of extended fasting.

Common Side Effects of Intermittent Fasting

While intermittent fasting can aid in weight loss, experts warn about several risks—especially during prolonged fasts like the 36-hour version. According to The Emily Program, a mental health and nutrition service, side effects may include:

• Intense hunger and cravings

• Fatigue and decreased energy levels

• Headaches and dizziness

• Digestive issues (constipation, bloating)

• Mood swings and irritability

• Bad breath

• Trouble sleeping

• Dehydration and frequent urination (polyuria)

• Nutrient deficiencies and malnutrition

• Hormonal imbalances and reproductive health concerns

These symptoms vary depending on individual health, diet history, and the fasting method used.

Limited Research and High Drop-Out Rates

Despite its growing popularity, clinical research on intermittent fasting remains limited. The Emily Program noted that many fasting trials are short-term and have high dropout rates, suggesting the diet may not be sustainable for most people.

A professor of metabolic physiology at the University of Bath, James Betts, also expressed skepticism. In an interview with The Guardian, he explained, “There are a lot of proposed benefits to running on fats, but most of the dramatic health claims haven’t been proven in human studies.”

Potential Mental Health Risks

Perhaps most concerning is the link between fasting and disordered eating. While intermittent fasting is not considered an eating disorder, consistently ignoring hunger cues may lead to a disordered relationship with food. Experts urge caution, especially for individuals with a history of restrictive eating or body image issues.

Final Thoughts: Is Intermittent Fasting Safe?

Intermittent fasting may work for some, but it’s not a one-size-fits-all solution. The 36-hour fasting trend, while effective in burning fat, can also trigger a range of negative side effects and health risks.

Before starting any fasting regimen, it’s important to:

• Consult with a healthcare provider or dietitian

• Start with shorter fasting windows

• Monitor how your body responds

• Avoid extreme fasting if you have a history of eating disorders or chronic health conditions