Girls typically start to gain weight as they go through puberty. Puberty is the process of physical changes through which a child’s body matures into an adult body capable of sexual reproduction. Puberty starts when the brain triggers the production of hormones that cause these physical changes. The timing and order of changes vary widely among girls. However, there are some general patterns of when pubertal changes tend to happen.
When Does Puberty Start?
On average, puberty begins between the ages of 8 and 13 years old for girls. But it may start as early as age 7 or as late as age 14. Puberty tends to start earlier for girls who have a higher body mass index (BMI) than average for their age. BMI is a measure of body fat based on height and weight. Girls who are overweight or obese tend to enter puberty at an earlier age.
Here is a general timeline of when pubertal changes typically happen for girls:
- Age 7-8: Early breast development may begin. The first signs are typically a small, tender lump under one or both nipples.
- Age 8-14: Breast development continues, pubic and underarm hair starts to grow, the vaginal discharge increases, and menstruation begins.
- Age 10-11: Rapid height growth occurs (growth spurt). Ovulation and fertility begins.
- Age 12+: Growth slows down and reaches adult height. Pubic and underarm hair becomes thicker and coarser. Acne may occur.
Keep in mind every girl goes through puberty at her own pace. It’s normal for changes to start earlier or later than average. If signs of puberty haven’t started by age 13-14, it’s a good idea to see a doctor.
Weight Gain and Growth Spurts
As a girl goes through puberty, her body begins to store more fat and grow taller. This leads to weight gain and growth spurts.
Some key facts about pubertal weight gain in girls:
- Girls gain about 20-25 pounds during puberty. This accounts for about 17-25% of adult ideal body weight.
- Up to half of this weight gain occurs during the peak growth spurt.
- Girls tend to gain weight across the whole body rather than exclusively in the hips and thighs.
- This pubertal weight and fat gain contributes to normal female body shape (e.g. hips, thighs, breasts).
The timing of the most rapid weight gain and growth spurt differs between girls:
- Early maturers tend to have their peak growth spurt around age 11.
- Average maturers around ages 12-13.
- Late maturers around ages 13-14.
In addition to fat, girls gain muscle mass and bone mass during puberty:
- Muscle mass doubles during puberty.
- 25-45% of adult bone mass is gained during adolescence.
Factors Influencing Weight Gain
Several factors influence the timing and amount of weight gain during puberty for girls:
Genetics
Genes play a major role in determining growth patterns during puberty, including weight gain. If a girl’s parent went through puberty early or late, she is more likely to follow the same pattern.
Nutrition
Consuming a nutritious, balanced diet supports healthy growth and weight gain during puberty. Girls who restrict calories or have disordered eating may experience delayed puberty and insufficient weight gain.
Physical Activity
Regular exercise promotes gaining muscle, bone mass and strength during puberty. But over-exercising or training rigorously could lead to problems like amenorrhea (missed periods).
Stress
High stress levels raise cortisol, which can disrupt pubertal development and influence weight gain patterns.
Body Fat Percentage
Girls who have a higher body fat percentage before puberty tend to gain more fat and enter puberty at an earlier age.
Chronic Disease
Certain chronic medical conditions like diabetes, celiac disease or hypothyroidism can affect growth and weight changes during puberty.
Medications
Some medicines may impact weight gain during puberty, such as steroids, anti-seizure drugs, growth hormone and psychoactive medications.
Healthy Weight Gain
While weight gain is a normal part of puberty for girls, the amount and patterns of gain can impact health:
- Gaining too much weight rapidly increases risk for obesity, which raises future health risks.
- Gaining too little weight can lead to delayed development, menstrual issues and low bone density.
Here are tips to support healthy weight gain during this growth phase:
- Eat regular, balanced meals and snacks. Don’t restrict calories.
- Include lean proteins, fruits, vegetables, whole grains and dairy.
- Stay hydrated by drinking water and milk.
- Limit junk food, fast food, sugary drinks and juices.
- Be active for at least 1 hour daily to build muscle and bone.
- Get enough sleep to allow for growth hormone release.
- Talk to a doctor if significant weight changes occur.
Body Image Concerns
Developing a new body shape can be challenging for girls. Having a healthy view of weight gain and body changes during puberty is important:
- Avoid focusing too much on the number on the scale. Pay attention to how you feel and fit in your clothes.
- Appreciate what your body can do and how it’s becoming stronger and more capable.
- Understand that weight distribution varies – focus less on problem areas.
- Surround yourself with positive social support and role models.
- Don’t compare yourself to media images of unrealistic, idealized bodies.
If you have ongoing struggles with body image, disordered eating or self-esteem, be sure to talk to a parent or doctor.
When to See a Doctor
Consult a pediatrician or family doctor if your daughter experiences:
- No breast development by age 13
- No menstrual period by age 15
- Periods suddenly stop for more than 90 days (amenorrhea)
- Failure to gain 4-5 inches in height per year during puberty
- Rapid weight gain or loss
- Signs of eating disorder
- Symptoms like vision changes, headaches or excessive tiredness
- Unexplained hair growth in girls
Puberty is a time of powerful physical changes. Staying connected with your daughter, encouraging healthy habits, watching for problems and seeing a doctor for any concerns can help ensure she stays happy and healthy as her body transforms into that of a woman.
Conclusion
Girls typically gain 20-25 pounds during puberty as their bodies grow and mature. This weight gain is necessary for normal development of the hips, thighs, breasts and other female attributes. The most rapid weight gain often occurs during the peak growth spurt, which happens around ages 11-14 for most girls. While pubertal weight gain is normal, focusing on healthy habits is important to avoid excess fat accumulation and obesity risk. Paying attention to any issues with development, eating patterns or self-esteem can help girls stay physically and mentally healthy as they blossom into womanhood.