When your teen is gaining weight, it can cause you to worry. Learn why this happens by understanding the six most common reasons for teen weight gain.
As the mom of four kids who have moved through the teen growth spurt, I’ve had firsthand experience with growing teens and weight gain. In my practice as a pediatric nutritionist, teens (and their parents) show up with concerns about weight.
In this article, I highlight the most common reasons for gaining weight in the teen. Often, parents are looking for a medical reason for weight gain, such as low thyroid (hypothyroidism), but in my experience, this is rarely the reason. Even so, most pediatricians and other healthcare providers will want to rule out a medical basis for rapid weight gain.
More often than not, though, weight gain at puberty is related to a teen’s stage of development, lifestyle, and/or daily food and eating habits.
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Normal Weight Gain vs. Teen Obesity
First, let’s clear something up. Weight gain is supposed to happen in the teen years.
It’s normal. Until the weight gets distributed and situated, the situation can look and feel awkward.
If you look at your teen’s growth chart, you’ll notice a surge in the weight and height curves around the time of adolescence. This reflects the normal uptick in weight gain and height growth.
However, some teens are gaining too much weight for their own good health. According to the Centers for Disease Control (CDC), the teen obesity rate is currently about 21% amongst 12- to 19 -year olds. Extra, unhealthy weight can lead to high blood pressure, high cholesterol, pre-diabetes, orthopedic problems, and more.
As a parent who may be worried about your teen, your first job is to do a reality check: Is this normal weight gain and growth, which you will see on the growth chart, or is this problematic?
Why is My Teen Gaining Weight?
Let’s look at the possible reasons why your teen may be gaining weight.
1. Growth Spurt Ages and Normal Growth
The teen body morphs quite a bit during the teen years. Did you know during growth spurts in boys more muscle is gained, while girls gain more fat?
Generally, girls get more curvy and boys get more muscular.
The timing of weight gain is something to note as well. The growth spurt ages differ for boys and girls. Typically, girls enter puberty around age 10 and start menstruating around 12 ½ years. Boys begin this process later, entering puberty around age 12 to 13 years.
What Age Do Girls Stop Growing?
Most girls have completed the majority of their growth by age 14 or 15, but this depends on when they started menstruation. Girls who are late bloomers will start their growth spurt later and finish later.
What Age Do Boys Stop Growing?
Boys begin their growth spurts about two years later than girls, so they can continue to grow into the late teens. Generally, you can expect boys to stop growing around age 17 or 18, however, some later bloomers will continue to grow into early adulthood.
Weight gain is normal at peak growth times and should not be a cause for worry. If your teen is experiencing normal weight gain, be as supportive as possible by focusing on my 7 strategies to support a teenage growth spurt.
2. Teens Make Poor Food Choices
In my own experience as a mom of teens, I’ve witnessed how food choices can get off track. If your teen is driving, that adds another challenge to the situation. Teens who can drive often find themselves heading out the door to social events that involve food.
“I’m heading to meet my friends for coffee!”
“We’re meeting for ice cream.”
“I’m getting dinner with my friend…”
As a result, food choices may not be healthy.
- Sugary drinks such as soda or flavored coffee drinks that pack a lot of calories, fat and sugar (not to mention caffeine).
- Sweets and treats like candy and ice cream.
- Fatty foods such as pizza, French fries and chips.
Having too many unhealthy foods in the diet disrupts a healthy food balance. This may contribute to extra, unhealthy weight gain.
3. A Teen Gaining Weight May Have Bad Eating Habits
[If you want to know the secret to success, it relies on using a diplomatic feeding style.]
As a result of increasing independence, I often see teenagers change their eating habits. They want more agency over their lives and this can include decision-making around eating.
It’s common for teens to:
- Skip breakfast
- Eat a light lunch
- Raid the pantry or refrigerator after school
- Eat late at night
If these tendencies become habitual eating patterns, they can lead to extra weight gain.
4. Teens Get Less Physical Activity
Teens are generally getting less physical activity than they were twenty or thirty years ago. I find it disheartening that schools nix regular physical activity at a time when our kids need it the most to help them balance their health, wellness and stress levels.
In high school, gym class is minimized to a few days a week and actual exercise may be less than that. Recess, or a break to encourage physical movement? Nope.
While some kids play a regular sport and engage in training most days of the week, studies show that athletes tend to sit around (quite a lot) when they’re not training, potentially minimizing some of the benefits of exercise.
Even if you have a teen who is not inclined to move, he or she can be encouraged to be physically active.
Exercise helps boost metabolism (aka calorie burning) and build muscle, both factors in maintaining a healthy weight and optimal body functions.
5. Excessive Use of Smart Phones and Computers Contribute to Teen Weight Gain
Did you know that 20% of US teens spend 5 or more hours a day on their screens (computer, smartphone, tablet, and video games)? This is contributing to more sedentary lifestyles for teenagers.
One 2016 study found that teens who spent 5 or more hours using smartphones and computers were twice as likely to drink more sugary drinks and less likely to exercise.
6. Lack of Adequate Sleep Encourages Eating
Does your teen stay up later and have a hard time getting up in the morning? During the teen years, the circadian rhythm shifts. This means teens get tired later than they did when they were younger.
As a result, they go to bed later. Yet, due to early school start times, they may need to rise early. This shortens their total sleep time, which may affect their ability to regulate their appetite and eating.
A 2016 study showed that inadequate sleep, poor sleep quality and late bedtimes were associated with extra food intake, poor food choices, and obesity in adolescents.
Teens function at their best when they get at least 8-10 hours of sleep each night. Obviously, getting enough sleep along with daily exercise and a healthy diet is the key to a healthy teen. Sleep is not a waste of time!
Written by: Jill Castle, MS, RDN
Published on: July 10, 2019
Updated on: July 9, 2019