In the journal PLOS One, researchers reveal that women who had more children had longer telomeres than women who had fewer children.

Telomeres are caps at the end of each DNA strand that protect our chromosomes - thread-like structures that contain all our genetic information - from damage.

Each time a cell replicates, telomeres become shorter. They eventually become so short that they stop protecting chromosomes, leaving them vulnerable to damage, which in turn causes our cells to age and stop functioning effectively.

Previously, animal studies have supported the "life history theory," suggesting that higher reproductive behavior is associated with accelerated biological aging.

However, this latest study, led by Prof. Pablo Nepomnaschy and Cindy Barha - both of Simon Fraser University in Canada - contradicts this theory.

A panel of health experts - including Dr. Lawrence Cheskin, founder and director of Johns Hopkins Weight Management Center in Baltimore, MD, and Kathie Beales, associate professor in the Division of Nutrition at the University of Utah - was enrolled by US News & World Report to review and rank 38 of the most popular diets.

Each diet was scored using seven criteria, including short- and long-term weight loss, nutrition, safety and ease of compliance. These ratings were used to rank each diet in nine categories, including best overall diets, best diabetes diets, best weight-loss diets, best commercial diet plans and easiest diets to follow.

Our rankings put hard numbers on the belief that no one diet is ideal for everybody, but the best food plans overall are sustainable," notes Angela Haupt, senior editor of US News.

Besides the rankings and data, each diet has a detailed profile that includes how it works, evidence that supports or refutes its claims and a nutritional snapshot - tools that, along with the advice of a physician or nutritionist, can help consumers invest in diets that suit their lifestyles and further their health and wellness goals.