Body mass index (BMI) has long been foundational in healthcare around the world. The simple equation(方程) of weight relative to height has been used to determine your risk for certain diseases. But researchers have been questioning the value of BMI in individual health assessment now.

BMI was never intended to measure individual health. It was developed in the early 1800s to study weight variations across entire population. BMI is a rigid number based on old data," says Fatima Stanford, a professor at Harvard Medical School. And it's far from perfect in terms of the cutoffs(分界点) designed to indicate risk, she added.

A study estimated that more than 74 million American adults were miscategorized(被误分类) as unhealthy or healthy based on their BMI alone. Nearly half of people considered over weight and 29percent categorized as obese were actually healthy. Thirty percent of those considered to be at a normal weight had heart issues.

Part of the problem is that BMI doesn't tell the difference between weight from fat and muscle. So bodybuilders and athletes with high muscle mass may be categorized as overweight or obese. And even among people who do have higher body fat, BMI doesn't tell physicians anything about how the fat is distributed—a key connection to disease risk.

Furthermore, BMI cutoffs are largely based on data from western populations, making it a problem to apply this measurement to the diverse American population. There's growing evidence that body composition varies from race to race. African Americans, for example, are likely to carry more fat around the hips than white Americans. A study showed that for black adults in the U. S. , having a higher BMI (25and over) did not carry the same risk of death as it did in white adults.

Regardless of the BMI category you fall into, it's important to find a healthcare provider who will look beyond that number to get a whole picture of your health. Because despite the view that people with a higher BMI have a greater risk for a number of diseases than thinner people, the research shows it's not that simple.

We sometimes think that everything was much better and easier in the past. It's one of the tricks our minds play on us, especially when we are in low spirits.

Actually, it's unlikely that things were objectively better in the past. This form of thinking is calledrosy retrospection, which is a well-studied cognitive bias. It happens because when we think about the past, we are more likely to focus on positive generalities than annoying details.

If you think back to a holiday with your family five years ago, you're likely to recall the beautiful views rather than the uncomfortable bed. In other words, the negative details disappear from our memory over time while the positive ones remain.

Rosy retrospection can influence how we make decisions, and it's one of the reasons why we easily return into problematic relationships. The longer it is since we experienced the negative influence of a relationship, the more likely we are to let the good memories outweigh the bad memories and to perhaps forgive unforgivable behavior. It's always a good idea to review our nostalgic (怀旧的) feelings with a healthy degree of doubt.

But rosy retrospection does serve an important purpose. It keeps us in a positive state of mind in the present and is important to our psychological wellbeing. In fact, people who tend to remember negative experiences more than positive ones are likely to exhibit psychological disorders. Research generally suggests that our happiest days are still to come. And even if they're not, it's still important to believe that they are. Don't shy away from looking upon the past with a certain degree of nostalgia. But, for the same reason, don't use the past as an excuse to be unhappy in the present.

Jeremiad Oleita thinks she may have a partial solution for two of our country's persistent problems: garbage and poverty. It's called the Chip Bag Project. The 26-year-old student and environmentalist from Detroit is asking a favor of local snack lovers: Rather than throw your empty chip bags into the rubbish, donate them so she can turn them into sleeping bags for the homeless.

Chip eaters drop off their empty bags at two locations in Detroit: a print shop and a clothing store, where Oleita and her volunteer helpers collect them. After they clean the chip bags in soapy hot water, they slice them open, ay them flat, and iron them together. They use liners from old coats to line the insides.

It takes about four hours to sew a sleeping bag，and each takes around 150 to 300 chip bags, depending on whether they're single—serve or family size. The result is a sleeping bag that is "waterproof, lightweight, and easy to carry around, " Oleita told the Detroit News.

Since its start in 2020, the Chip Bag Project has collected more than 800, 000 chip bags and, as of last December, created 110 sleeping bags.

Sure, it would be simpler to raise money to buy new sleeping bags. But that's only half the goal for Oleita—whose family moved to the United States from Nigeria a decade ago with the hope of attaining a better life—and her fellow volunteers. "We are dedicated to making an impact not only socially, but environmentally, " she says.

As Oleita said, "There's the symbolism of using bags that would otherwise land in the rubbish and using them to help the homeless. It's a powerful reminder that environmental injustice and poverty often go hand in hand. "