Research suggests that those with a BMI of 19 to 22 enjoy the greatest longevity.
Participants whose BMIs were between 40 and 49.9 were more than twice as likely to die during the study period than those whose BMI was in the optimal range of 22.5 to 24.9.
Compared with individuals of healthy weight (BMI 18·5–24·9 kg/m2), life expectancy from age 40 years was 4·2 years shorter in obese (BMI ≥30·0 kg/m2) men and 3·5 years shorter in obese women, and 4·3 years shorter in underweight (BMI <18·5 kg/m2) men and 4·5 years shorter in underweight women.
This should be roughly in the range of 15-20% body fat. Higher body fat levels in women are generally not a health problem until at least 25%. Men should generally avoid spending prolonged periods of time below 10% body fat.
Conclusions: Obesity and overweight in adulthood are associated with large decreases in life expectancy and increases in early mortality. These decreases are similar to those seen with smoking. Obesity in adulthood is a powerful predictor of death at older ages.
Scientists say waist-to-hip ratio better measure for healthy weight than BMI.
BMI Under 18.5 Is Risky
Adults who are underweight, with a BMI under 18.5, have a 1.8 times greater risk of dying than those with a BMI of 18.5 to 24.9, according to the researchers. BMI is a rough estimate of the amount of body fat a person carries.
Findings based on millions of deaths suggest that shorter, smaller bodies have lower death rates and fewer diet-related chronic diseases, especially past middle age. Shorter people also appear to have longer average lifespans.
Severe obesity (BMI 40 to 50, which is still uncommon) reduced life expectancy by about 10 years; this is similar to the effect of lifelong smoking.
Because muscle weighs more than fat, people who are very muscular may have a high BMI. Older people. In older adults it is often better to have a BMI of 25 to 27, rather than under 25.
Your body mass index, or BMI, is the relationship between your weight and your height. A BMI of 20-25 is ideal; 25-30 is overweight and over 30 is obese. If your BMI is under 18.5, you're considered underweight. If your BMI is 18.5-20, you're a bit underweight and can't afford to lose more.
Indeed, because muscle mass decreases with age, it might be wise to shift the healthy BMI range for older adults. The same BMI could mean very different things at age 25 versus age 75.
At the end of the study, about 16 percent of the men and about 34 percent of the women survived to the age of 90. In fact, the authors found that women who were taller than 5 feet 9 inches were 31 percent more likely to reach 90, compared to those who were under 5 feet 3 inches.
In this study, men who were 5'2″ or shorter were more likely to have a protective form of the FOX03 gene, and lived the longest. Those over 5'4″ had shorter lifespans. Shorter men were also shown to have less incidence of cancer, and lower fasting insulin levels.
* A 1992 study of nearly 1,700 dead guys found that, on average, men shorter than 5'9” hung around till the ripe old age of 71. Men taller than 6'4”, on the other hand, checked out around the age of 64.
But NIST physicists have made it a lot more personal - a scale of about 1 foot - and showed that you even age faster if you are taller than your relative. The good news is you won't be able to see the difference, that one foot difference in height adds about 90 billionths of a second over a 79-year lifetime.
A BMI below 13.5 can lead to organ failure, while a BMI below 12 can be life-threatening. Note, however, that BMI alone is not enough to make a diagnosis of anorexia and is solely a possible indicator.
BMI below 18.5 is underweight (too low). BMI 18.5 to 24.9 is normal weight (just right). BMI 25 to 29.9 is overweight (high). BMI 30 and higher indicates obesity (very high).
Several large scale prospective studies15 16 17 18 19 20 21 22 23 24 and pooled analyses (each with 900 000 to 1.46 million participants)2 14 25 have reported increased risk of all cause mortality with greater BMI, and most of these found the lowest risk among participants with BMI in the range of 20 or 22.5 to 24.9.
BMI (body mass index), which is based on the height and weight of a person, is an inaccurate measure of body fat content and does not take into account muscle mass, bone density, overall body composition, and racial and sex differences, say researchers from the Perelman School of Medicine, University of Pennsylvania.
One of the main issues with BMI is that it cannot account for the difference between muscle and fat. Because muscle tissue is more dense than fat, many athletes and bodybuilders are considered overweight according to BMI despite being in peak athletic health.
Medical experts rely on BMI because it is simple, cheap, and generally accurate. At times, however, the index misclassifies patients because it does not distinguish fat from muscle.
Obesity has a similar impact on life expectancy. But while smoking certainly carries numerous and substantial health risks, obesity poses even more.
Normal weight is a BMI of 18.5 to 24.9. A BMI of 25 to 29.9 is considered overweight and a BMI of more than 30 is considered obese. A BMI of less than 18.5 is underweight. The researchers analyzed 3.6 million adults and found that a BMI of 21 to 25 is associated with the lowest risk of morbidity.