Intermittent fasting side effects (and how to avoid them)

The typical first-days effects

When you start, your body is switching from sugar to fat for fuel. It is normal to feel some of this during the first week: hunger at your usual meal times, headaches, mild dizziness, irritability (hangry) or trouble focusing. These usually fade as you adapt.

Headaches: the number one cause

Headaches while fasting usually come from dehydration and low sodium, not from fasting itself. The fix: drink more water and add a pinch of salt or electrolytes. It can also be caffeine withdrawal if you changed your coffee routine.

Dizziness and energy dips

• Hydrate and watch your electrolytes.
• Do not pair your first week with an aggressive calorie deficit.
• If you get dizzy standing up, stand up slowly (a temporary drop in blood pressure).
• Dial back exercise intensity for the first few days.

Hunger and irritability

Hunger comes in waves of 20-30 minutes and passes, especially if you drink water or black coffee. Irritability eases as your body learns to keep blood sugar steady. Starting gradually (12/12 → 14/10 → 16/8) cuts both down a lot.

When it is NOT normal and you should stop

Talk to your doctor and stop if you get fainting, strong heart palpitations or confusion, or if you have medicated diabetes (risk of hypoglycemia). Fasting is not recommended during pregnancy or breastfeeding, for minors, if you are underweight, or with a history of disordered eating.

How Ayúname helps

Ayúname reminds you to hydrate and lets you start gradually, stretching the window little by little so adapting is smooth and you do not quit in week 1.