 Early onset of puberty is considered a risk factor for a number of diseases in adulthood, including hormone-related cancers, a shorter lifespan, metabolic syndrome, and cardiovascular disease. The conventional thinking has been that the reason the age of puberty has been getting earlier and earlier is because our children have been getting fatter and fatter. Well, our kids have been getting heavier, especially in the United States, were number one. But while the age of a girl's first period has been dropping in the US and Asia, in Europe, despite their kids getting heavier too, there hasn't been a steady decline in puberty onset, so maybe it's less about how much kids are eating and more about what they're eating. The most consistent link between diet and premature puberty has been animal protein consumption. For example, every gram of daily animal protein intake, the weight of a paperclip, has been associated with about a 17% increase in the risk of girls starting their periods earlier than age 12. Why this link between animal protein and premature puberty? Well, we know meat increases the levels of the growth hormone IGF-1, and that alone is associated with early onset puberty. But maybe animal protein is just a proxy for the endocrine disrupting chemicals that build up the food chain in animal products. Recent reports have found significant associations between the exposure to environmental pollutants and sexual maturation. This was done over in Europe in the US. A similar relationship was found with the flame retardant chemicals, for example, which are found mostly in poultry and fish, unless you're eating cat food. Over the last three decades, human exposure to these levels of industrial pollutants in the US have increased from virtually non-existent to almost everyone crying around now. They appear to have multiple adverse effects, but if all the potential toxicities endocrine disruption, meaning hormonal disruption, may be the main concern in children. Girls with the most circulating in their bloodstream appeared up to 10 times more likely to start their periods early. But since these chemicals are found mostly in fish and poultry, maybe the levels of these chemicals in their bloodstream is just kind of a proxy for their meat consumption. Whatever the reason, animal protein intake is associated with early onset puberty, whereas plant protein has the opposite effect. Children with higher levels of vegetable protein start puberty seven months later than average, and children eating more animal protein may start puberty seven months earlier than average. A soy seems most protective. Girls with the highest levels of dietary isoflavone intake, phytonutrients, and soy foods may experience their onset of breast development approximately seven or eight months later than girls with the lowest levels of intake. What effect might these shifts have on disease rates? Well, delays in the onset of, in the timing of puberty, in response to dietary, beneficial dietary habits, higher intakes of vegetable protein and soy, and lower intakes of animal protein, may be of substantial public health relevance. A later age of starting one's period is related to a reduced risk of breast cancer, and a later first period is associated with lower total mortality, meaning a longer lifespan. Hence the delay in the timing of puberty by approximately seven or eight months, which is achievable with dietary modifications, either more plants or fewer animals, may translate into about a 6% reduction in breast cancer risk and up to a 3% decrease in total mortality. And it's not just a problem in girls, boys eating more meat and childhood appear to be more likely to grow up with a kind of abdominal fat deposits that increase risk for heart disease.