This content is for reference only. Please consult your doctor before applying.
🍽️ Intermittent fasting (IF) can be a powerful tool for weight loss, metabolic health, and mental clarity—but only when it’s done correctly. One of the most overlooked mistakes, especially among women, is not eating enough during the eating window. While it may seem like a faster route to weight loss, chronic under-eating can lead to fatigue, muscle loss, hormone imbalances, and long-term health issues.
⚠️ Are You Eating Too Little Without Realizing It?
Many people assume that feeling tired or weak during fasting is normal. But if these symptoms persist even after you eat, they may be signs you’re simply not eating enough:
- You feel fatigued, dizzy, or lightheaded after meals
- You’re always cold, even in warm environments
- Your sleep becomes disrupted or you wake up hungry at night
- You’ve lost your menstrual cycle or it has become irregular
- You’re losing weight rapidly, especially muscle mass
- You have constant food cravings or anxiety around meals
These are red flags that your body is not getting the fuel it needs—regardless of how “clean” or “disciplined” your fasting routine is.
👩⚕️ Why Women Are More Affected
Women’s bodies are highly sensitive to energy availability, especially due to the hormonal fluctuations that regulate fertility, mood, and metabolism. When calorie intake is too low:
- Estrogen and progesterone levels drop, disrupting the menstrual cycle
- Thyroid function slows down, reducing metabolism
- Cortisol levels rise, causing fatigue, anxiety, and fat storage around the belly
- Ovulation may stop altogether, especially with prolonged under-eating
For women, especially those of childbearing age, eating too little can be more dangerous than eating too much.
🧮 How to Calculate Your Minimum Calorie and Nutrient Needs During IF
Fasting doesn’t mean eating less than your body needs. It means eating within a defined time frame while still meeting your nutritional requirements.
🔢 Step 1: Calculate Your Basal Metabolic Rate (BMR)
This is the number of calories your body needs to stay alive at rest.
A rough estimate:
BMR (women) ≈ 10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) – 161
BMR (men) ≈ 10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) + 5
🔄 Step 2: Add Activity Level
- Sedentary: BMR × 1.2
- Lightly active: BMR × 1.375
- Active: BMR × 1.55
- Very active: BMR × 1.725
👉 This gives your Total Daily Energy Expenditure (TDEE)—the amount of calories you should aim to eat within your eating window.
🥦 Step 3: Balance Macronutrients
- Protein: ~1.2–2g per kg of body weight (more if you’re active or want to preserve muscle)
- Fat: ~30–35% of total calories
- Carbs: Fill in the rest based on your energy needs and preferences
Even within an 8-hour window, you should strive to eat at least 80–90% of your TDEE—especially if you’re active.
✅ Tips to Meet Nutritional Needs During IF
- Don’t skip meals during the eating window. Aim for at least two solid meals.
- Add energy-dense healthy foods like avocado, nuts, seeds, full-fat yogurt, and oily fish.
- Use smoothies if you struggle with large meals—they’re easier to digest and can pack nutrients.
- Listen to your body—extreme hunger, fatigue, or mood swings are signals, not signs of discipline.
- Track your intake for a few days to get a realistic view of your calorie and protein levels.
🧘♀️ Balance Is Key
Intermittent fasting isn’t about restriction—it’s about rhythm. Undereating can sabotage the very goals that bring people to fasting in the first place: better energy, a healthier body, and long-term sustainability. By eating enough nutrient-dense meals during your eating window, you’ll not only feel better—you’ll get better results.
Reference
🍽️ Mayo Clinic Health System – Intermittent fasting: Fad or solution?
⚠️ Summa Health – Here’s the scoop on intermittent fasting
🔗 https://www.summahealth.org/flourish/entries/2019/07/here-is-the-scoop-on-intermittent-fasting
🧠 Healthline – 9 Potential Intermittent Fasting Side Effects
🔗 https://www.healthline.com/nutrition/intermittent-fasting-side-effects
