You don’t have to be a specific “legal age” to fast, but it does depend on the type of fasting, your health, and why you’re doing it.

1. Religious fasting (like Ramadan)

If you’re asking about fasting in Islam:

  • Fasting is only obligatory once a person reaches puberty (they’re considered religiously accountable at that point).
  • Before puberty, kids can fast sometimes to “practice,” but it’s not required, and adults are supposed to make sure it’s not harming them (no extreme weakness, dizziness, etc.).
  • Puberty can happen at different ages (roughly early teens), so there isn’t one exact age number for everyone.

Some scholars and teachers also say things like:

  • Start encouraging short or occasional fasts around 10–12 if the child is healthy and able.
  • Make it fully regular only when they are clearly mature enough physically and mentally.

2. Intermittent / weight‑loss fasting

If you mean “fasting” like skipping meals or doing intermittent fasting for weight loss or health:

  • Many health and nutrition discussions warn against minors (under 18) doing strict fasting because their bodies and brains are still growing.
  • People in fasting communities often say that teens can be especially at risk for eating disorders, body‑image issues, or overdoing it.
  • That’s why you’ll see comments like “don’t fast seriously until 18+” or “only under medical supervision.”

So even if you’re, say, 15–17, doing long or extreme fasts just for weight loss is usually not recommended without a doctor who knows your history.

3. How to think about “how old”

A better question than “what age” is “am I healthy, still growing, and is a doctor/guardian on board?”:

  • If you’re under 18 , it’s safest to only fast in a gentle, supervised way, and only if a doctor (not just the internet) says it’s okay.
  • If it’s for religion , the usual teaching is: not required before puberty, gently encouraged and adjusted to the child’s ability, and never to the point of making them ill.
  • If you already struggle with body image, bingeing, or restricting, any kind of fasting can easily make things worse.

4. Quick checklist for you

Ask yourself:

  1. Am I still growing a lot (most teens are)?
  2. Is this mainly about weight or hating how I look?
  3. Have I talked to a parent/guardian and a doctor or nurse?
  4. If I try a fast, do I feel dizzy, faint, or unwell?

If the answer to 2 is “yes” or you notice scary symptoms (fainting, chest pain, extreme weakness), you should stop and talk to an adult or health professional as soon as you can.

5. Bottom line

  • For Islamic fasting : it becomes required at puberty, not at some fixed age like 18, and kids can practice earlier only if it’s safe for them.
  • For diet/health fasting : serious or extended fasting usually isn’t advised for people under 18 without medical supervision, because of growth and mental‑health risks.

If you tell me your age and the reason you want to fast (religious, health, weight, something else), I can help you think through a safer plan to talk about with an adult in your life.

Information gathered from public forums or data available on the internet and portrayed here.