Recent reports that obesity can shorten life span were no more than quick bites for most media outlets.

Even so, there is more to chew on here. The two studies, published in esteemed medical journals, pointed to the fact being overweight in our 20s, 30s and 40s can make part of our 60s, 70s or 80s vanish.

Dutch scientists wrote in the Annals of Internal Medicine that people who are overweight at 40 are likely to die three years sooner than others who are slim. Obese 40-year-olds (more than 20 percent over healthy body weight) risked closer to six to seven years. Dropping the weight in later years might not completely reverse the damage.

“Even if you lose weight later on, you still carry a higher risk of dying,” said Dr. Serge Jabbour, director of the weight-loss clinic at Thomas Jefferson University Hospital in Pittsburgh.

Then in the Journal of the American Medical Association, Johns Hopkins University researchers introduced a new measurement for determining the health risks of obesity, calling it “years of life lost” or YLL. The study showed obesity in younger adult life, especially the 20s and 30s, significantly increases YLL.

The study identified optimal ranges of body mass index or, sorry, another acronym, BMI. For white individuals, the BMI range associated with highest longevity (and lowest YLL) is 23 to 25 (read on to learn how to calculate your BMI).

For African-Americans, the numbers broaden to 23 to 30, but some experts anticipate this range will tighten in future studies using more detailed analysis of mortality data among blacks.

Although BMI is regularly used to indicate risk for illness or death — a value greater than 30 is a red flag — one concern is BMI unfairly negatively rates individuals who have put a noticeable amount of muscle on their frame.

To calculate BMI by hand (many Internet sites provide convenient calculation), divide your weight in pounds by 2.2 to get your weight in kilograms. That’s Answer No. 1.

Then divide your height in inches by 39.4 to get your height in meters. Now multiply your height in meters by itself to get meters squared. That’s Answer No. 2.

Divide No. 1 by No. 2 to get your BMI.

The Dutch researchers found being overweight and age 40 creates the same longevity risk as a regular smoking habit. In a JAMA editorial accompanying the Johns Hopkins study, Harvard physician Dr. JoAnn E. Manson noted that obesity will soon overtake smoking as the No. 1 cause of preventable death in the U.S.

Dr. Robert Kushner, medical director of the Wellness Institute at Northwestern Memorial Hospital in Chicago, said the new measurements such as YLL and old standbys such as BMI can help put obesity “closer to the center of the radar screen.” But what convinces most people is “not being able to bend over to tie your shoes, being out of breath or not fitting into a dress.”

“We have to create a society that supports people to scale down their weight rather than enabling them to scale up,” said Kushner.

In his new book, “Dr. Kushner’s Personality Type Diet” (St. Martin’s, $23.95), co-authored with wife and nurse practitioner Nancy, the Northwestern physician explains the “scaling up” phenomenon of gaining weight with each life stage. He said it can start in childhood, continue in college and keep spiraling upward because of career and family demands.

“I call it false weight,” said Kushner. “For one patient, it might be the freshman 10, the stressful-job 6, the honeymoon 4 and the baby 6. That’s 26 pounds of false weight.”

In his 20 years of practice at the University of Chicago and Northwestern, Kushner has noticed certain tendencies among patients. He has devised seven “eating personality” types and lays out diet plans for each type. The two most common eating-personality types are “hearty portioner” and “unguided grazer.” Hearty portioners eat oversized portions (two to five times the norm), eat too fast and usually feel stuffed. They tend to suffer from indigestion and sluggishness.

Unguided grazers don’t plan meals. Their meals and snacks can vary widely by day, though convenience is a common denominator. These folks eat relatively higher amounts of calories, fat and salt.

Kushner has also devised exercise personality and coping personality types.

“The most common exercise personality type is what we call ‘hate-to-move strugglers,”‘ said Kushner. “What does that tell you about America? We need to keep looking for ways to help people break their old patterns of scaling up.”

You can visit www.doctorkushner.com to take the mini-quiz for your eating personality type.