About one-third of American girls aged 10 to 14 are on a diet. Many of them resort to cigarette smoking, vomiting, fasting and other unhealthy behaviors in an attempt to lose weight. Over time, these habits can lead to full-blown eating disorders and affect overall health. The key to achieving a healthy weight is to understand your metabolism and take the steps needed to keep it functioning optimally.
Resting metabolic rate in teenage girls depends on several factors, such as their weight, body composition, activity levels and genetics. Some people have a faster metabolism than others, which allows them to burn more calories at rest.
If you have a low metabolic rate, you can lose weight without resorting to crash diets and strenuous workouts. Your body is still growing, so it's important to get enough calories. The key to weight loss is to stay active and make smart food choices on a daily basis.
Factors That Affect Your Metabolism
Metabolism and body weight are strongly connected. Think of your metabolism as your internal engine. It encompasses all the chemical reactions that occur in a living organism to sustain life. As Harvard Health Publishing notes, metabolism can be defined as the rate at which the body burns calories for fuel.
Some people have a fast metabolism and can eat everything in sight without gaining a pound. Others are not so lucky. Your metabolic rate depends largely on genetics. Other factors, such as your age, gender, body composition, activity level and eating habits, play a role, too.
For example, men have more lean mass and less fat compared to women of the same age and weight, so they expend more energy on a daily basis. That's because muscle is more metabolically active and burns more calories than fat. Strength training, for instance, can help you build lean mass, which in turn, leads to a faster metabolism.
Energy Expenditure in Adolescents
Your metabolic rate depends on your age, among other factors. According to a July 2014 review published in Medicine & Science in Sports & Exercise, resting metabolic rate (RMR) — which represents the rate at which your body burns calories at rest — is 20 to 25 percent higher in young people compared to those over 70 years old and decreases with age in both genders. As researchers point out, resting energy expenditure is related to the amount of lean muscle mass.
As a teen girl, you have a faster metabolism than your parents and other adults. This means that it should be easy to control your weight through a balanced diet and exercise.
A September 2015 review in the American Journal of Clinical Nutrition states that young people, especially girls, are more likely to become obese during puberty due to the increase in fat mass associated with this period of growth. Furthermore, obesity tends to persist into adulthood.
The good news is that both resting metabolic rate and basal metabolic rate are higher in pubertal teens than prepubertal adolescents. Despite the increase in fat mass, teenagers can easily maintain their weight due to their high energy expenditure.
However, it's hard to tell how many calories you burn at rest; your energy expenditure depends on your current weight, muscle-to-fat ratio, exercise habits and other factors. Consider using an online calculator to determine the exact number of calories burned throughout the day.
How to Lose Weight Safely
A teenager's body is still growing. Crash diets, starvation, skipping meals and other bad habits can affect your hormone levels and physical development. According to the American Academy of Pediatrics, calorie needs are higher during early adolescence. Teen girls need approximately 2,200 calories per day, while teenage boys should get around 2,800 calories daily.
If you're overweight or obese, you need to create a caloric deficit to lose weight. Basically, it's necessary to burn more calories than you take in. This can be done in several ways:
- Exercise more
- Decrease your calorie intake
- Eat less and get more exercise
- Eat foods with a high thermic effect
Let's take lean meat, fish and eggs, for example. These foods are high in protein, which requires more energy to digest and break down than fat and carbohydrates. Protein can increase your metabolic rate by up to 20 to 30 percent. Carbs, on the other hand, will raise your metabolism by just 5 to 10 percent, while dietary fat can boost your metabolic rate by up to 5 percent. For the record, this increase in metabolism usually only lasts for up to three hours after you've eaten.
Furthermore, protein curbs hunger and increases satiety, as reported in a review published in Nutrition & Metabolism in November 2014. This nutrient has a positive impact on the hormones that regulate appetite, making it easier to reduce your food intake. Therefore, you can boost your metabolism and burn more calories simply by increasing your protein intake.
Cut back on sugar and empty calories. According to a research paper published in the January 2018 edition of the journal Nutrients, breakfast cereals, soda and bread are the primary sources of sugar in a teenager's diet. These foods and beverages have little or no nutritional value and contribute to rising obesity rates.
Keep your diet varied and make smart food swaps to cut calories. Replace white bread with whole grain bread, swap soda and energy drinks for fruit-infused water or unsweetened tea and substitute white rice and pasta with veggies. Choose brown rice over white rice, fill up on leafy greens and start your day with whole grains instead of breakfast cereals.
Make exercise a habit and stay active throughout the day. Any type of physical activity, whether it's swimming, jogging, weight training or team sports, burns calories and facilitates weight loss. Don't overdo it, though — your body needs time to recover from exercise, so be sure to get enough rest between workouts.
- Minnesota Association for Children's Mental Health: "Teens, Social Media and Body Image"
- Harvard Health Publishing: "Does Metabolism Matter in Weight Loss?"
- MedlinePlus: "Can You Boost Your Metabolism?"
- NCBI: "Examining Variations of Resting Metabolic Rate of Adults: A Public Health Perspective"
- The American Journal of Clinical Nutrition: "Energy Expenditure and Intake During Puberty in Healthy Nonobese Adolescents: A Systematic Review"
- Healthy Children: "A Teenager’s Nutritional Needs"
- BetterHealthChannel: "Metabolism"
- BMC Nutrition & Metabolism: "A High-Protein Diet for Reducing Body Fat: Mechanisms and Possible Caveats"
- MDPI: "Sources of Added Sugars in Young Children, Adolescents, and Adults With Low and High Intakes of Added Sugars"