Should I Fast During Puberty?

Everyone · Explainer · Updated October 1, 2026 · LearnLife Editorial

What Is Fasting and How Does It Work?

Fasting means choosing not to eat food for a set period. Some people fast for parts of the day (like skipping breakfast), while others may go 24 hours or more without eating. When the body doesn’t get food, it first uses stored sugar (glucose) for energy, then moves on to burning fat. For example, a 13-year-old who stops eating after dinner and skips breakfast gets energy from stored glucose to get through the morning. But if fasting happens often or lasts too long, it can cause tiredness, dizziness, or difficulty concentrating.

During puberty, the body grows quickly and needs a steady supply of energy and nutrients. Parts like the brain, bones, muscles, and organs all rely on food to build and work well. If a teenager fasts too often or for long periods, their body may not get enough fuel. For instance, a 15-year-old who tries a popular 16-hour fasting routine every day might not eat enough calories to support growth, leading to fatigue or poor school performance.

Fasting also affects hormones. Growth hormone and sex hormones increase during puberty to promote development. Without enough nutrition, these hormones can be disrupted, which might slow puberty and cause mood swings or irregular periods.

Why Does Puberty Matter for Nutrition?

Puberty involves many body changes that need extra food and nutrients. Teenagers grow taller, build muscles, and strengthen bones. Hormones like androgens and estrogens guide these changes. To support growth, the body needs:

• Extra calories for energy
• Protein for muscles and tissue
• Calcium and vitamin D for bones
• Iron for blood, especially for girls who start menstruating
• Healthy fats for brain and hormone health

If fasting reduces eating, the body misses these nutrients. For example, a 14-year-old girl who skips breakfast and lunch might miss iron from foods like beans or lean meat, risking anemia and tiredness.

Good nutrition also supports mental health. Balanced meals keep blood sugar stable, which helps mood and focus. Missing meals can cause irritability or anxiety, making puberty’s emotional ups and downs harder.

Since puberty builds the foundation for adult health, skipping meals or fasting can delay growth and cause other problems.

What Are the Risks of Fasting During Puberty?

Fasting during puberty can lead to several risks:

• Nutrient Deficiencies: Skipping meals limits vitamins and minerals needed for growth. For example, too little calcium can weaken bones.
• Low Blood Sugar: Without regular food, blood sugar drops, causing dizziness, headaches, or fainting, which can be dangerous during activities.
• Slowed Growth: Without enough calories and protein, growth in height and muscles may slow.
• Mood Swings: Hunger can cause irritability, anxiety, and difficulty concentrating.
• Menstrual Problems: Girls might miss periods or have irregular cycles, which can affect future health.
• Risk of Disordered Eating: Early fasting might lead to unhealthy relationships with food or eating disorders.

For example, a boy who fasts daily to lose weight may feel tired during sports and struggle at school, harming his development.

How Is Fasting Different From Healthy Eating or Dieting?

Fasting, dieting, and healthy eating are often confused but are different:

• Fasting means not eating for certain hours or days, often to lose weight or for religious reasons, skipping all or most food.
• Dieting usually means eating less or choosing healthier foods but still eating regularly.
• Healthy eating means eating balanced meals consistently to support growth and energy.

For teens, healthy eating includes:

• Having three meals a day and snacks if needed
• Including proteins (meat, beans), whole grains, fruits, vegetables, and dairy or alternatives
• Avoiding skipping meals or cutting out whole food groups without advice

For example, a teen wanting to control weight might eat smaller portions and choose fruits and veggies instead of skipping meals or fasting.

Fasting deprives the body of needed energy and nutrients, which is risky during growth. Dieting with guidance focuses on balance and nourishment.

When Can Fasting Be Done Safely During Puberty?

Some teens fast for religious reasons, like during Ramadan. To fast safely during puberty:

• Talk to a healthcare provider before starting, especially if there are health issues.
• Drink plenty of water during non-fasting hours to stay hydrated.
• Limit fasting hours by following religious guidelines, like eating before dawn and after sunset.
• Choose nutrient-rich foods when eating to get enough energy, protein, and vitamins.
• Avoid intense exercise while fasting to prevent exhaustion.

For example, a 16-year-old fasting for Ramadan might eat eggs, vegetables, and whole grain toast before sunrise and a balanced dinner with chicken and fruit after sunset, supporting growth despite fasting.

If fasting causes dizziness, tiredness, or mood changes, stop fasting and seek help from a trusted adult or doctor.

What Should Teens Do Instead of Fasting During Puberty?

Rather than fasting, teens should focus on steady, balanced eating habits:

1. Eat three meals daily: breakfast, lunch, and dinner, plus snacks if hungry.
2. Include all food groups: protein, whole grains, fruits, vegetables, dairy or alternatives.
3. Drink water throughout the day.
4. Eat when hungry and stop when full to avoid overeating.
5. Limit sugary drinks and processed snacks, opting for whole foods.
6. Avoid skipping meals, even if busy; plan quick, healthy snacks like fruit and nuts.
7. Talk to parents, teachers, or healthcare providers if unsure about eating habits.

For example, a teen feeling hungry after school might eat an apple and a handful of almonds instead of skipping food or eating candy.

If a teen wants to manage weight or body image, they should consult a healthcare provider or counselor rather than trying fasting or strict diets.

How Can Parents and Educators Help Teens Eat Well During Puberty?

Parents and educators can support teens by:

• Preparing balanced meals with protein, grains, fruits, and veggies.
• Encouraging regular meal routines, like eating breakfast before school.
• Talking openly about puberty, nutrition, and body changes to reduce confusion.
• Watching for signs of unhealthy eating, like skipping meals or mood changes.
• Promoting positive body image and self-care over dieting or weight loss.
• Modeling healthy eating themselves to set an example.

Schools can help by providing nutritious lunch options and teaching about puberty and nutrition. For instance, teachers can explain why calcium is important for bone growth during puberty.

What Related Topics Should You Explore To Support Healthy Puberty?

Understanding puberty and nutrition together helps teens make good choices. Related articles to read include:

• How to Check Your Puberty Stage: Learn about physical milestones and growth.
• Healthy Eating Tips for Young Adults: Practical advice for balanced nutrition.
• Should I Work Out During Puberty?: How exercise supports growth and health.

These resources provide more information to support a healthy transition through puberty.

Frequently asked questions

Can fasting stunt height growth during puberty?

Yes, fasting can limit the calories and nutrients needed for bone growth, potentially slowing height development during puberty. Consistent nutrition is essential for reaching full adult height.

Is it normal to feel hungrier during puberty?

Yes, because puberty causes rapid growth and body changes, teens often feel hungrier and need more food to fuel their developing bodies.

How can teens get enough calcium if they don’t eat dairy?

Teens can get calcium from fortified plant-based milks, leafy green vegetables like kale or broccoli, tofu, almonds, and fortified cereals to support bone health.

What should a teen do if they want to lose weight during puberty?

They should focus on balanced meals with appropriate portions and regular physical activity. It’s important to avoid fasting or restrictive diets and to consult a healthcare provider for personalized advice.

Can fasting affect menstrual periods in teenage girls?

Yes, fasting can disrupt hormone levels, causing irregular or missed periods. This can affect reproductive health and should be discussed with a healthcare provider if it occurs.

Who should teens talk to if they struggle with eating habits or body image?

Teens should reach out to trusted adults like parents, school counselors, or healthcare providers who can offer support and help connect them to appropriate resources.