Neptune grass colonies have existed for up to 200,000 years, making them the oldest living creature in the world. The colony grass can renew itself, unlike most creatures, humans included. However, people can increase their chances for longevity, though much is circumstantial. Below are three ways that research shows how people can max out their longevity.

1.       Be Monacan. People from this miniscule country of 30,539 resident have a life expectancy of 89.7 years, making them the oldest living national group, according to the World Factbook published by the CIA. Americans are at a disadvantage, ranking 50th worldwide with a life expectancy of 78.4 years. Angolans have the shortest life expectancy at 38.8 years. The likely reason? Monaco are typically very wealthy, an predictor of longevity. The World Health Organization in 2008 found that social factors drove the huge differences in longevity worldwide. The report states that countries at all levels of income, health and illness follow a social gradient: the lower the socioeconomic position, the worse the health. The global health group formed the Commission on Social Determinants of Health, with the goal of closing the health gap between rich and poor within a generation.

2.       Have good genes. Scientists have long known that genetics plays at least some role in human longevity. An international team found people 100-years or older had one of three specific genetic signatures in an experiment that scanned the genomes of 801 centenarians and compared them with 914 healthy controls. The group found 130 genes linked to old age and found that many determine risks to ailments such as coronary artery and Alzheimer's disease. The journal PLoS ONE published the study Jan. 18.

3.       Restrict your calories. Researchers have known since 1935 that restricting calories in the diet of rats increases their lifespans. This observation extends from yeast to rhesus monkeys, and a multicenter study is currently underway to determine if people in a semi-starved state live longer. Volunteers for the CALERIE study consume 25 percent fewer calories than they typically do during a day. The result is not only weight loss, but lower risk for diabetes, heart disease and hypertension. It's a lot of normal food, Rachel Murray, a CALERIE volunteer told Time Magazine in 2010. You just have to plan what you're eating. The hypothesis that restricting calories extends life even has an advocacy group, the CR Society International that guides people through calorie restrictive lifestyles that can be difficult to maintain.