Thin may be in, but by 2049, the average women will be a touch "chubbier and shorter," according to a Yale University study on natural selection gleaned from two recent generations of women.
Actually, thin is sort of out given the unhealthy and sometimes deadly effects of starvation diets on models who face the unemployment line if they don't remain in the words of one article "boney apparitions." Things are headed in the opposite direction anyway, says the new study.
Writing in the Proceedings of the National Academy of Sciences, Sean G. Byars and three fellow researchers said traits can be predicted for the next generation of women based on factors with 2,000 women in the famous Framingham Heart Study which began in 1948. For nine years, I lived in Framingham from whose population the initial 5,209 men and women were rescruited for the study which continues to this day.
Descendants of the women in The Framingham Heart Study on average are predicted to weigh about a kilogram more and be two centimeters shorter. If that's bad news, here's the good: women will also have lower blood pressure and chloresterol. Ths study also found women will have babies up to five months earlier and go through menopause up to 10 months later, resulting in a longer child-bearing period.
The study results would seem to validate "evolutionary biological principles" posited by Charles Darwin in "The Origin of the Species" 150 years ago.
"We found that natural selection is acting to cause slow, gradual evolutionary change," the researchers said in the PNAS article. The study strongly disputes the contemporary and population notion that medicine-inspired longevity means that natural selction no longer applies.
"The reason is that traits that enable women to have children will continue to be subject to selection. As a first step, the Yale researchers measured the individual reproductive success of two generations of more than 2000 women who participated in the Framingham study and had reached menopause. They then surveyed the traits that conferred reproductive success. After adjusting for environmental factors such as income, education and lifestyle choices such as smoking, the researchers estimated the heritability of traits by applying correlations among all relatives. They also adjusted for the indirect effects of selection by measuring the impacts the traits have on each other – such as whether high blood pressure is correlated with lower or higher age of sexual maturity."
Using statisical analysis, the researchers were able to determine which traits would be "conferred" on the future generation of women.