Weight gain can happen at any age, but there are certain times in life when people tend to put on extra pounds. Here is an overview of the most common ages when people gain weight and why it happens.
Childhood
Weight gain often starts in early childhood. According to the CDC, about 1 in 5 school-aged children and adolescents in the United States has obesity. There are a few reasons weight gain happens more frequently at this age:
- Growth spurts – Children naturally gain weight as they grow taller. Growth spurts happen at different times for different kids, but they are common around ages 6-8 for girls and ages 10-15 for boys.
- Poor eating habits – Many kids develop less healthy eating patterns as they gain more independence. Easy access to processed, high-calorie foods also contributes.
- Less active play – With more academics, organized activities, and screen time, many children get less active free play than previous generations.
To curb unhealthy weight gain in childhood, experts recommend limiting processed foods, getting at least 1 hour of exercise per day, and promoting healthy home eating habits from an early age.
Adolescence
The teenage years are another period when people commonly gain weight. According to one national survey, about 1 in 5 adolescents in the U.S. are obese. Some reasons include:
- Puberty – Hormone changes during puberty increase body fat. Girls gain about 15 pounds, while boys gain about 30 pounds on average.
- Unhealthy habits – Many teens make poor food choices and do not get enough exercise. Peer pressure can reinforce bad habits.
- Stress and emotions – Teenagers deal with many pressures. Emotional eating and bingeing are common responses.
To help teens maintain a healthy weight, experts suggest being a role model for healthy eating, encouraging physical activities they enjoy, and discussing strategies to manage stress.
Early adulthood
The college years and early 20s are when many young adults first live independently. This new freedom often leads to weight gain with:
- Less healthy eating – Without parental oversight, young adults often opt for fast food, processed snacks, sugary drinks, and alcohol.
- Irregular schedules – College students and young professionals often have late nights or irregular meal times.
- Less activity – With new jobs and responsibilities, many people in their 20s get less exercise than previously.
To avoid unhealthy weight gain at this age, experts suggest planning healthy snacks and meals, using campus dining halls wisely, and continuing to exercise regularly.
Pregnancy and postpartum
It is normal to gain weight during pregnancy and keep some weight postpartum. According to the IOM, healthy pregnancy weight gain depends on pre-pregnancy BMI:
| Pre-pregnancy BMI | Recommended Weight Gain |
|---|---|
| Underweight (less than 18.5) | 28-40 lbs |
| Normal weight (18.5-24.9) | 25-35 lbs |
| Overweight (25.0-29.9) | 15-25 lbs |
| Obese (over 30) | 11-20 lbs |
Gaining within these ranges lowers the risks for mothers and babies. Postpartum, it’s typical to keep 5-10 pounds after having a baby. To lose excess weight after pregnancy, experts suggest breastfeeding, eating nutrient-dense foods, and resuming exercise once cleared by a doctor.
Midlife
Many adults start gaining about 1 to 2 pounds per year in middle age. Reasons include:
- Slower metabolism – Basal metabolic rate slows about 2 to 3 percent per decade after age 30.
- Loss of muscle – Lean muscle mass decreases with age, further slowing metabolism.
- Hormone changes – Reduced estrogen in women and testosterone in men increases fat storage.
- Lifestyle changes – People tend to be less active and eat more calories as they age.
To combat midlife weight gain, experts suggest strength training to build muscle, getting at least 150 minutes of moderate aerobic activity per week, and eating a balanced diet with appropriate portions.
Menopause
Many women gain weight around menopause, with an average increase of about 5 pounds. However, some women gain far more. Weight gain during menopause is linked to changes in hormones, including:
- Declining estrogen – Estrogen helps keep fat distributed to the hips and thighs. As it drops, fat accumulates around the abdomen.
- Lower testosterone – Testosterone helps increase muscle mass and trim fat. Declining levels allow more fat storage.
To manage menopausal weight gain, providers suggest eating foods rich in calcium and vitamin D, exercising regularly, and considering short-term hormone therapy if appropriate.
Older adulthood
Gaining weight continues to be common among older adults for several reasons:
- Less activity – Many older adults struggle with limited mobility and have difficulty exercising.
- Medications – Some drugs commonly prescribed for older adults cause weight gain as a side effect.
- Underlying illness – Conditions like hypothyroidism or depression can disrupt metabolism.
- Loss of taste and smell – This leads to overuse of salt, sugar, and fats when cooking and seasoning food.
Strategies to limit unhealthy weight gain in older age include walking or chair exercises, engaging in hobbies, and eating filling, nutritious foods.
Conclusion
While weight gain can happen at any age, the most common times for unhealthy weight gain include childhood, adolescence, early adulthood, middle age, menopause, and older adulthood. Weight gain is often associated with growth, life changes, hormonal changes, aging, and decreased activity levels. Following a healthy lifestyle with good nutrition and regular exercise can help limit excessive weight gain during these vulnerable periods of life.