When Do Teenagers Gain the Most Weight?

Adolescence marks a time of significant change. Teenagers experience new schools, shifting friend groups, different responsibilities and a body that undergoes rapid growth and development. Adapting to all these changes does not come easily. In particular, teenagers may feel anxious about the weight gain that occurs at this time. In looking to understand their situation, they may ask, when do teenagers gain the most weight?

Teenagers usually gain the most weight around puberty which can be age 13 to 18. Many teenagers gain the most weight around 15 to 18 years old. On average, teenagers should gain about 10 to 15 pounds or more each year.

The exact age when significant weight gain occurs will differ according to the individual. Leading up to and at the beginning of puberty, teens may see an increase in appetite and weight as their body prepares for the rapid growth and development that occurs during maturation. As height jumps up during puberty, teenagers may also see a correlated increase in weight. Girls tend to start puberty between ages 8 and 13 while boys start between ages 9 and 14. The rate of these changes will slow down dramatically in late adolescence as puberty ends. Teenagers should take note that heightened weight and height at this stage is normal and healthy.

Continue reading to learn more about adolescent height and weight and other related topics.

Do Teenagers Gain Weight After Puberty?

The large upward trend in weight commonly stops with the end of puberty. However, some teenagers may continue to see more gradual weight gain afterwards due to a host of reasons.

First, if teens did not attain a healthy weight during earlier years, their body may continue to put on weight for optimal well-being. By adulthood, females need around 21% or more of body fat while men need at least 8% body fat. Bodies cannot properly function without adequate weight or body fat.

Second, lifestyle may change as teenagers get older to include more sedentary activity. This decrease in movement during the day can cause an energy imbalance where calorie output is less than input. Teenagers with less physical activity may also see a decrease in muscle mass, which lowers their resting metabolism. Setting aside sixty minutes each day for movement can help teenagers stay fit and brings many other health benefits.

Third, older teenagers gain more autonomy over their food. Less structure may lead to more snacking, fewer balanced meals and other dietary practices that can contribute to excess calories or decreased nutrition. This poor nutrition can cause weight gain. However, as a modifiable risk factor, teenagers can improve their eating habits by focusing on including nutrient dense foods throughout the day and listening to their bodies.

Fourth, sleep provides so many benefits to increase well-being and longevity. When teenagers or adults do not get enough sleep, many areas can suffer including eating and exercise habits. Poor sleep can also impact hormones and inflammation in the body. The impact of poor sleep in the mentioned areas contributes to possible continued weight gain after puberty. Teenagers should continue to strive for 8-10 hours of sleep consistently each night.

Fifth, medical conditions can cause unwanted weight gain. This elevated weight can occur from an imbalance in hormones, digestive issues, water retention and a slowed metabolism. Medication side effects can also cause weight gain with an increased appetite or altered metabolism. Talk to your healthcare provider about your concerns and they can help direct you proper to treatment options.

Constant weighing can create disordered thoughts and cause unnecessary stress. Fluctuations in weight, even up to five pounds, can occur daily from body water shifts and digestion. For this reason, teenagers may want to avoid the scale or limit weigh-ins for health visits. Instead of weight, teenagers should focus on how they feel and whether they can create lifestyle habits that support lasting well-being.

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When is Teenage Weight Gain a Concern?

Worried about your teenager’s weight gain? Part of growing up involves gaining weight. However, excess weight gain is detrimental to a teenager’s health. How can a teenager know when to feel concerned about their weight gain? The most important piece of advice would be to talk to your healthcare provider. They can access a variety of tools, information and expertise to better determine health status.

A large amount of weight gain can occur during puberty. Using several years and months of BMI data can help teenagers understand whether their weight gain may be a cause for concern. Plotting these points on an age and sex appropriate BMI growth chart should show a pattern that follows a similar percentage curve on the graph. Large deviations or consecutive jumps in percentiles may indicate a need for further assessment.

Teenagers can also take a look at their daily choices. An increase in appetite often precedes a growth spur. In this case, eating more food is a normal and healthy response. However, eating more due to boredom, emotion or stress can cause an excess of calorie consumption. The same experience can occur with eating mostly ultra high processed foods or those with high amounts of sugar and saturated fat. Increased sedentary time or lack of of physical activity can also contribute to weight gain. Noticing these types of behaviors or other less healthful habits, along with a large amount of weight gain may indicate a need for change.

It can be normal for a teenager to gain 15 to 30 pounds (7 to 14 kg) in a year, but check in with a doctor yearly to check overall weight trends, especially if your teen is gaining more than 20 to 30 pounds (9 to 14 kg) in a year.

When is the Last Growth Spurt in the Teenage Years?

On average, children grow 2.4 inches (6 cm) per year during childhood. This growth slows down right before puberty and then jumps to about 3.15-3.55 inches (8-9 cm) per year through puberty.

Growth tends to slow down differently for males and females. In females, peak growth occurs before menstruation. The growth will then slow down but continue for a couple of years. Females generally finish maturation and growth around the age of fourteen or fifteen. Males start puberty later and end later as well. Their growth spurts tend to start two years after girls and while many finish rapid growth by the age of sixteen, others still see some more gradual growth into their later teenage years.

Why do 13-14 year Olds Gain So Much Weight?

Around the ages of thirteen and fourteen, most teenagers experience the rapid growth and development of puberty. The increase in height will correlate with an increase in weight. Furthermore, hormones will shift body fat and muscle mass percentages in teenagers. These changes can also affect weight. In fact, some kids will gain 20-30 pounds in one year during puberty.

How Can a Parent Help Encourage Body Acceptance During The Teenage Years?

Teenagers experience a lot of stress regarding their body and appearance. The changes that occur with puberty can make it especially difficult for youth to accept or like their bodies. Parents can provide support at this time to promote body acceptance and encourage self-confidence.

Parents can start by listening and expressing compassion. The feelings these teenagers have about their bodies are real and should not be brushed away. Instead, parents can express understanding and share openly about what happens with puberty. Other steps to take include:

1. Avoid Diet Talk

Teenagers do not need to diet. Cutting calories, foods or food groups leads to malnutrition. Teenagers who constantly hear a parent talk about “bad” foods or cutting calories may develop a dangerous diet mentality or disordered eating.

2. Appreciate Your Own Body

Similarly, teenagers will internalize the negative comments parents express about their own or others’ bodies. Instead of criticizing anyone’s body, including your own, talk with respect and appreciation for everything the body does. Help your teenager recognize the positive about their body.

3. Focus on Behavior, Not Weight Goals

Weights fluctuate day to day and year to year. No exact science exists to determine the perfect weight for an individual. In the end, it’s not about the number on the scale but about the overall health of your teen and their lifestyle habits. With weight being such an unreliable measure of health, parents should support teenagers in creating healthy behavior habits, not weight centered goals. A good example could be to limit screen time to two hours daily, increase physical activity, or focus on eating more fruits and vegetables and less fast food.

4. Stop With Comparisons

Individuals are meant to be different. Comparing your child to others does not lead to the best outcomes. This comparison should also not occur for yourself. Working on your own self-confidence does wonders for putting you in a place where you can protect your child’s self confidence. Placing limits on social media will also help with keeping unhealthy comparisons from hurting a teenager.

What Are Ways a Teenager Can Stay Healthy?

What can a teenager do to ensure health when the scale can’t be relied on as a health measurement? The yearly preventative visit to the doctor will provide the best option for an objective measurement of a teenager’s health status.

On top of this visit, teenagers can take a look at their daily habits. Wellness comes from repeatedly making choices that support lasting well-being. Some of the pillars of health include daily movement, balanced meals and snacks, adequate sleep, stress management, staying hydrated and avoiding risky behaviors. Teenagers can assess their own life and start with small realistic goals to improve their health in one or some of these areas:

1. Daily Movement

Health professionals recommend at least sixty minutes of physical activity each day for teenagers. This movement does not need to only consist of sports, running or other vigorous exercises. It can include movement like yoga, dancing, waking with friends, playing with the dog or doing chores. The sixty minutes also can happen throughout the day in shorter spurts rather than all at once.

2. Balanced Meals and Snacks

A balanced eating pattern focuses on inclusion, not exclusion, of foods. Teenagers should strive for meals and snacks with carbohydrates, protein and fats to ensure lasting energy and fullness. Nutrient dense foods work alongside favorite treats and snacks in moderation to increase satisfaction. Severe restriction or dieting can reduce nutrition and pleasure while fostering an unhealthy relationship with food.

3. Adequate Sleep

Teenagers need 8-10 hours consistent and quality sleep. Skipping out on this important part of the day will reduce health both in the short and long term. Sleep provides the body with an opportunity to build and repair the body, strengthen the mind, reduce inflammation and undergo many other important processes.

4. Stress Management

Stress is and always will be a part of life. However, staying in a constant state of unmanaged stress will harm both physical and mental health. Learning how to manage stress while young will offer many benefits and improve quality of life. Some techniques involve talking to someone, prioritizing tasks, learning to say no, meditation, breathing exercises, therapy and medical intervention when needed.

5. Staying Hydrated

Water performs many vital functions in the body. Dehydration, even by a small amount, will decrease overall function, performance and mental clarity. Teenagers will all require different amounts of fluid to stay adequately hydrated due to differences in weight, physical activity, gender and environment. Drinking fluids throughout the day and maintaining a pale yellow urine will help teenagers meet their unique needs.

6. Avoiding Risky Behaviors

The experience of adolescence usually means gaining more independence and trying new things. Teenagers will feel tempted to push boundaries. However, risky behaviors like unprotected sex, underage drinking, drugs, tobacco, vaping, and violence lead to lasting ill effects and are just not worth it.

As a Registered Dietitian Nutritionist, I’ve worked with hundreds and thousands of people in their health goals, especially teenagers. I’ve seen a lot of what works and what doesn’t work to get to a healthy weight! My very best tips for a healthy teenager are included in my ebook:

Teenage Healthy Weight Plan – The Right Way to Lose Weight for Teens

What’s in the eBook?

75+ pages with insightful infographics for quick tips
11 week plan with actionable steps for teens to develop healthy habits

5 week meal plan to help you eat well and eat right
Sections directed at both teens, as well as their parents
Healthy snack list recommendations

Tips for gaining or losing weight the healthy way
Calculations for daily calorie and protein needs
…And More

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