Many people struggle with weight loss, often turning to strict diets, pills, or extreme routines. Recently, intermittent fasting has gained attention as a possible solution, with celebrities and athletes promoting it. Unlike traditional diets, intermittent fasting focuses on when you eat, not what you eat.
Historically, people did not eat on strict schedules. As Dr. Vicki Catenacci explained, “People now eat, on average, throughout a 14-hour period each day,” meaning the body rarely rests from digestion. Fasting provides that break, helping the body reset and shift how it uses energy.
During fasting, the body goes through several stages. After about eight hours, blood sugar drops and energy use begins shifting. Around twelve hours, fat becomes the main fuel source, and insulin levels stay low, which may support fat loss. By sixteen hours, a process called autophagy becomes more active, allowing the body to recycle damaged cells. After twenty-four to thirty-six hours, fat burning and cellular repair intensify, and autophagy can reach its peak.
However, fasting can also cause side effects. According to The Emily Program, possible issues include “excessive hunger, headaches, dizziness, digestive issues, mood changes, bad breath, sleep disturbances, dehydration, excessive urination, and nutrient deficiencies and malnutrition.” Because of these risks, experts caution against extreme fasting.
Harvard professor Dr. Frank Hu noted that fasting may help with weight loss but is not necessarily better than standard calorie reduction. “You can’t follow it now and then and expect any significant changes,” he said, adding that consistency matters more than perfection.
Personal stories vary. Some people report better focus and energy, while others find longer fasts challenging. One individual warned, “Important: I don’t recommend anyone try this without careful preparation… This isn’t medical advice.”
Experts agree that fasting is not suitable for everyone. The safest approach is balance, moderation, and consulting a healthcare professional before starting, especially for those with medical conditions or a history of eating disorders.
