Why did I faint 1/2 hour after lunch when i am on intermittent fasting?

Recently i have a spell of fainting after i eat 1x Chicken Burger, 1 x Chicken Wing, 1 x Potatoe. It was after 1/2 hour after i consume my food. As i start to get up, i start to see stars on my vision, i try to shake it off but as i walk, my vision start to disappear and before i know it, i was on the ground. Luckily my friends were beside me. 

As i google on the Chat GPT, it gives some answer what could have happened. This is the first time i encounter such an issue from intermittent fasting. I need to watch on how to break my fast which is my first meal of the day. Gradually ease into the body needs. 

From Chat GPT. 

Fainting (syncope) 30 minutes after lunch, especially while practicing intermittent fasting (IF), can happen due to several factors. Here's a breakdown of the possible causes — but this is not medical advice and you should consult a doctor for a proper diagnosis.

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🧠 Top Reasons Why You Might Have Fainted After Lunch During IF

1. Reactive Hypoglycemia (Low Blood Sugar After Eating)

• When you fast, your body becomes more insulin sensitive.

• After breaking your fast with a high-carb or sugary meal, your blood sugar spikes, then crashes rapidly due to high insulin release.

• That sharp drop (reactive hypoglycemia) can lead to dizziness, sweating, and fainting.

Signs: Shaky hands, heart palpitations, cold sweat before fainting.

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2. Postprandial Hypotension (Drop in Blood Pressure After Eating)

• Blood is redirected to your digestive system after a meal.

• If your blood vessels don't compensate properly, your blood pressure drops, leading to light-headedness or fainting.

More common in: People over 60, those with autonomic nervous system issues, or on certain medications.

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3. Dehydration or Electrolyte Imbalance

• IF sometimes leads to reduced water and salt intake.

• This can lower blood volume, reducing blood pressure.

• When you eat and sit/stand afterward, this could trigger fainting.

Clues: Dark urine, dry mouth, leg cramps, fatigue.

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4. Too Much Food Too Fast

• A large meal, especially with refined carbs, can overload the digestive system.

• This triggers a strong parasympathetic ("rest and digest") response, lowering your heart rate and blood pressure — possibly leading to fainting.

🧪 Probable Cause: Reactive Hypoglycemia + Postprandial Hypotension

After fasting for 16 hours (16:8 IF), your body is more sensitive to insulin. The meal you broke your fast with — Popeye’s chicken burger, potato, fried chicken wing — is:

• High in refined carbs (burger bun, potato)

• High in fat and salt (fried items)

• Low in fiber and slow-digesting nutrients (e.g., whole grains, vegetables)

This combination can:

1. Cause a quick spike in blood sugar (from the bread and potato).

2. Your body then responds with a surge of insulin → leading to a rapid drop in blood sugar (reactive hypoglycemia).

3. Plus, a large, greasy meal after fasting sends a lot of blood to your gut → drops blood pressure (postprandial hypotension).

4. Result: You may feel dizzy, lightheaded, then faint.