Poor nutrition alters the ratio of lean mass to body fat and delays the onset of menarche. In the US, the age at menarche decreased by 3 years since 1840 due to improvements in the population's nutritional status. Underweight females generally experience menarche at later ages than normal weight females.
Some health problems and being underweight can cause delayed puberty. Less commonly, a problem with hormones causes it.
The researchers found that girls with higher total body fat had differences in reproductive hormone levels, developed mature breasts more slowly and got their first period earlier than girls with lower total body fat.
Frequently overweight and obese children are taller for their age and sex and tend to mature earlier than lean children. The increased leptin and sex hormone levels seen in obese children with excessive adiposity may be implicated in accelerated pubertal growth and accelerated epiphyseal growth plate maturation.
In girls at least, research suggests a possible link between early puberty and obesity. "A number of studies have shown that girls who are overweight are more likely to have puberty early, and that girls who are underweight -- and especially anorexic -- undergo puberty later," says Kaplowitz.
Puberty in women normally occurs between 11 and 14 years of age. If a child reaches a particular weight (around 45 kg or 100 lb), the onset of puberty is triggered. The heavier the child, the earlier puberty occurs, possibly affecting risk of later disease.
Does body weight affect height? A 2011 study suggests that there is “no association between adult height and weight status.”
Changing Body Shape
Boys tend to look a little chubby and gangly (long arms and legs compared to the trunk) just prior to and at the onset of puberty. They start to experience a growth spurt as they progress further into puberty, with the peak occurring during the later stages of sexual maturation.
The authors found an association between %BF and resumption of the menstrual cycle, establishing a cut-off point of 21.2% of total body fat.
Body fat plays a significant role in reproduction. Sex hormones are fat-soluble and are stored in the body's fat layers. Women that have a low BMI produce a reduced amount of estrogen which can lead to an abnormal menstrual cycle. Amenorrhea, or the lack of a menstrual cycle, is a result of a low BMI.
Results: The onset of puberty occurred when the boys' weight gained 40.33±9.03 kg (median 39.00) and BMI was 18.62±3.12 kg/m2 (median 17.80), whereas the late stage was reached at weight of 62.44±10.39 kg (median 61.00) and BMI 21.47±2.84 kg/m2 (median 21.20).
Most often, it's simply a pattern of growth and development in a family. A guy or girl may find that his or her parent, uncle, aunt, brothers, sisters, or cousins developed later than usual, too. This is called constitutional delay (or being a late bloomer), and it usually doesn't need treatment.
The most common cause of delayed puberty is a functional delay in production of gonadotropin-releasing hormone (GnRH) from the hypothalamic neuronal networks that synergize to initiate the episodic or pulsatile release of the GnRH.
Delayed puberty is when: boys have no signs of testicular development by 14 years of age. girls have not started to develop breasts by 13 years of age, or they have developed breasts but their periods have not started by 15.
Studies indicate that the body's fat content must account for 17% of the body's weight before menarche can occur and that, at age 18 years, the fat content must be at least 22% for the maintenance of regular menstrual cycles.
According to the American Journal of Clinical Nutrition, there are healthy body fat percentages based on your age. For people aged 20 to 39, women should aim for 21% to 32% of body fat. Men should have 8% to 19%. For people 40 to 59, women should fall between 23% to 33% and men should fall around 11% to 21%.
Men and women need different amounts of fat. For a man, 2–5% fat is essential, 2–24% fat is considered healthy, and more than 25% classifies as obesity. For a woman, 10–13% fat is essential, 10–31% fat is healthy, and more than 32% classifies as obesity.
Delayed puberty also may occur when the testes produce too little or no hormones. This is called hypogonadism. This can occur when the testes are damaged or are not developing as they should. It can also occur if there's a problem in parts of the brain involved in puberty.
During puberty, boys and girls will have a growth spurt and grow to their adult height. So that means girls who start puberty the latest will still be getting taller in their mid-teens. For boys, the latest to reach puberty will still be getting taller into their late teens.
In some children, weight spurts happen before height spurts. Other children just gain more weight than they need for their height. This is how children become overweight. Parents, family members, and friends can all help a child who is at risk of or has become overweight.
At approximately age 9 years, those who became obese or overweight stood approximately 3.5 cm taller than those who had normal weight as an adult. Differences in height were slightly greater by age 11 years, whereby those who became obese were, on average, 4.5 cm taller than the normal weight group.
Obesity hormones indeed do affect growth. It has been shown that tall and obese children exhibit variation in the ghrelin gene [30], and leptin was shown to stimulate growth even in the presence of caloric restriction [31].
Hormone-driven changes are accompanied by growth spurts that transform kids into physically mature teens as their bodies develop. It's important for them to have healthy eating habits, a well-balanced diet, and some physical activity each day to ensure continued growth and proper development during these years.
Delayed puberty affects about 2% of adolescents. Most commonly, puberty may be delayed for several years and still occur normally, in which case it is considered constitutional delay of growth and puberty, a common variation of healthy physical development.