New Delhi, 14 May 2025: Intermittent fasting (IF) has become one of the most popular health trends in recent years. From weight loss to improved metabolism, better blood sugar control to enhanced longevity. It’s praised as a miracle fix for many health concerns. But while It can offer real benefits when done correctly. It isn’t for everyone — and the potential health risks are often overlooked.
If you are thinking of starting intermittent fasting, here’s what experts say about its lesser-known side effects.
What Is Intermittent Fasting?
Intermittent fasting is an eating pattern that cycles between periods of fasting and eating. Common methods include the 16:8 method (16 hours of fasting, 8-hour eating window), the 5:2 diet (eating normally for five days, significantly reducing calories on two days), and alternate-day fasting.
This diet doesn’t focus on what you eat, but rather when you eat. While this simplicity is appealing, it can cause unexpected side effects — especially if started abruptly or without medical advice.
Fatigue and Low Energy
One of the most common side effects of intermittent fasting is feeling tired or low on energy. When the body is deprived of regular meals, especially in the beginning, it may struggle to maintain stable blood sugar levels. This can leave you feeling sluggish, irritable, or even dizzy.
Disrupted Sleep Patterns
Intermittent fasting can interfere with your circadian rhythm, especially if your last meal is early and you go to bed hungry. This can result in difficulty falling asleep, staying asleep, or feeling rested upon waking. Poor sleep can negatively affect overall health, metabolism, and mood.
Digestive Issues
Long fasting windows followed by large meals can upset the digestive system. Some people report bloating, constipation, acid reflux, or indigestion, particularly if they consume too much food too quickly during the eating window.
Nutritional Deficiencies
Skipping meals regularly without planning can lead to nutrient deficiencies. Intermittent fasting may cause a person to miss out on essential vitamins, minerals, and fiber, especially if the diet lacks variety or balance.
Hormonal Imbalances (Especially in Women)
Women may be more sensitive to the effects of fasting due to hormonal fluctuations. In some cases, It has linked to disrupted menstrual cycles, fertility issues, and changes in stress hormone levels like cortisol. It’s essential that women consult a healthcare provider before starting this dietary approach.
Disordered Eating Patterns
For some individuals, intermittent fasting can trigger unhealthy eating behaviors. The restrictive nature of fasting can lead to overeating or binge eating during feeding windows, and may worsen pre-existing conditions like anorexia, bulimia, or orthorexia.
Who Should Avoid Intermittent Fasting?
Intermittent fasting is not suitable for everyone. People with diabetes, low blood pressure, eating disorders, pregnant or breastfeeding women, and those on certain medications should avoid it unless supervised by a medical professional.
While intermittent fasting can offer benefits, it’s not a one-size-fits-all solution. Listen to your body, start gradually, and consult a healthcare provider to determine if it’s right for you. Understanding the potential health risks and side effects is just as important as knowing the benefits.
