Teenagers acquire weight gradually as they mature. Although a healthful increase in weight is necessary, excess weight gain in teens and the accumulation of additional calories might be concerning. The most prevalent causes of significant weight gain in teenagers are a poor diet and a sedentary lifestyle, including lack of physical activity. However, hormonal changes during adolescence and an underlying medical condition in a few cases can also induce a sudden increase in weight in teenagers. While teenagers need to keep excessive weight gain in control, they should not deprive themselves of the regular weight increase that is necessary for their healthy development. Dive into this post as we discuss the appropriate weight gain for teens, some common reasons for excessive weight gain, and what can be done to maintain a healthy weight.

What Should Be the Ideal Weight of Teens? 

To determine the ideal weight of the teen, you need to consider several factors besides their age.

The US Center for Disease Control and Prevention (CDC) and the American Academy of Pediatrics recommend the use of BMI calculator to determine if a teen has normal weight, is overweight or obese (1). The BMI calculator considers the height and age of the teenager in determining their weight threshold. BMI for teens is interpreted differently, which is why you should refer to a BMI chart, such as the one developed by the CDC, standardized for children. The CDC says, “Because there are changes in weight and height with age, as well as their relation to body fatness, BMI levels among children and teens need to be expressed relative to other children of the same sex and age (2).” Therefore, the weight of a teen is evaluated in comparison to other teens and is assigned as a percentile. The minimum is the 5th percentile, and the highest is the 95th percentile. When the teen’s BMI is equal to or greater than the 95th percentile, they are considered obese since it means the teen’s weight is greater than 95% of teens.

Ultimately, the teen’s BMI score on the percentile chart will determine if they are of a healthy weight or not.

BMI Percentile Table and Weight Status 

Source: US Centers for Disease Control and Prevention 

BMI Calculation and CDC Charts 

You can calculate the BMI of the teen using the following formula:

Weight (kg)/ (Height in meters x Height in meters) (Weight (lb) x 703)/ (Height in inches x Height in inches)

Round off the number to one decimal place. For example, 22.554 becomes 22.5. You can calculate the BMI of your child and plot it on the chart right at home: CDC BMI Chart For Boys CDC BMI Chart For Girls

What Causes Excess Weight Gain In Teens?

Here are a few reasons that contribute to excess weight gain in teenagers (3).

1. Eating unhealthy food

Unhealthy snacking between meals can accumulate excess calories that cause weight gain. This is particularly common when teens feel “bored” and go every now and then to the kitchen or the refrigerator looking for food that makes them feel better. Teens are likely to gain weight if they eat high-calorie, low-nutrient fast food even if they have a nutritious diet at home. Access to junk food combined with the freedom that their pocket money gives them can also result in building unhealthy eating habits. Regular binge eating of fast foods and processed foods can lead to weight gain.

2. Insufficient physical activity 

The teenager needs to get adequate exercise to stay in good health. When a teen has no physical activity, then they invariably gain weight. Children who do not eat junk food may also be at risk of putting on over weight if they do not exercise at all. Teenagers burn fewer calories when at rest, according to a study (4). The study noticed that 15-year-olds burn 400 to 500 fewer calories per day when at rest, compared to what they did at the age of ten years.

3. Puberty

Puberty alone may not cause significant weight gain. However, the growth spurt tends to cause increased hunger, which may accelerate weight gain in teens who eat in excess and do not get enough physical activity. Children in their early teens (13 to 14-year-olds) are likely to gain weight naturally as a result of hormonal changes during puberty. Weight gain may be more prominent among girls (5). The child may gain about 6.5 pounds (3 kilograms) in a year after puberty (6).

4. Psychological reasons 

The changes in the body make adolescents highly self-conscious and sensitive to their figure. They may unnecessarily compare themselves to their peers and be under pressure of having the “ideal body” (7). The dissatisfaction of not having the perfect body may lead to depression, which in turn could lead to unhealthy eating habits, and thus weight gain (8). Several teens have a flawed opinion that they are fat even when they are not. In the long run, this could lead to reinforcement of the belief. Some experts state that a teenager’s constant belief that they are fat can lead them to gain excess weight (9). Stress is also linked to weight gain. Research suggests that stress and depression can lead to higher consumption of sugary and fat-rich foods (10). Food is quite likely to work as a coping mechanism to alleviate the feelings of depression and chronic stress.

5. Health reasons

Hypothyroidism is a condition where the thyroid gland becomes underactive and produces lesser thyroid hormone, one of the symptoms is an increase in weight (11). The teenager is also likely to feel tired and fatigued most of the time. This is most common in girls, particularly if some other woman in the family has thyroid disease.

Cushing’s syndrome is a rare medical condition that causes the body to produce an excess of cortisol, which is the stress hormone produced by the adrenal glands (a gland that lies over each kidney). One of the significant symptoms of the condition is weight gain. Accumulation of fat around the base of the neck is another symptom. Children with Cushing’s syndrome tend to become obese and also grow slowly (12). Certain medicines can also lead to excess weight gain due to the compounds in them. Sometimes, medications can cause complications that in turn, lead to weight gain. An example is glucocorticoids, which is a type of steroid hormone commonly used in the treatment of immune system disorders like asthma and lupus. Long-term use of glucocorticoid can cause Cushing’s syndrome, which in turn leads to weight gain.

Excessive weight gain can be controlled through changes in lifestyle and diet. But if that doesn’t help, you may have to consult a medical professional.

When To Be Concerned About Weight Gain? 

Consult a doctor about your teen’s weight gain if:

The child has extreme weight gain beyond 16 years of age and even towards the end of the teen years (2) (4). You sense the teen is gaining weight due to binge eating, which itself may have been caused by constant peer pressure, body image issues, or some other matter that is stressing them out. The weight gain seems to have begun after the kid was prescribed medicine. In such a case, talk to the doctor about it. The body develops abnormally high deposits of fat around the neck, face, and the abdomen. The skin on the abdomen has reddish-pink stretch marks (these are the symptoms of Cushing’s syndrome).

The child also appears tired, dull and complains of muscle aches.

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