I recently saw a headline that startled me: “Harvard scientists find weight loss is not always good.” But then I wondered: With obesity rates and the incidence of Type II diabetes continually climbing, when exactly is weight loss bad? You might think: This study comes from Harvard, so it must be true, right? And it’s “scientists” who are claiming this, not the average person.
So, to find out what was behind the headline, I read the article. Then, I read the actual scientific paper, published in September 2022 in PLOS Medicine, that was referenced in the article.
The study is fascinating — a dense read, but very enlightening. It included participants from the Nurses’ Health Study (NHS), the Nurses’ Health Study II, NCI (NHSII), and the Health Professionals Follow-Up Study (HPFS). A total of well over 200,000 people were included in this review, and they were followed from 1988 until 2017, an enormous undertaking!
In an attempt to summarize the study (without reducing it to just a headline), the researchers were looking at weight loss and the subsequent impact on developing Type II diabetes. The weight loss was accomplished through a variety of methods, including exercise, low-calorie diet, low-calorie diet and exercise, fasting, commercially available weight-loss plans, the use of diet pills, and combinations of all of these. They found that a loss of 4.5 kilograms, approximately 10 pounds, actually did help reduce the risk of developing diabetes later in life. Interestingly, this impact on decreasing diabetes risk was maintained even if the study subject did not maintain weight loss. So, a one-time loss of 10 pounds actually did help the patient in the long run.
When the data was more specifically analyzed, there were some interesting findings. This benefit of reducing the risk of diabetes based on a 10-pound weight loss was limited to patients with a BMI of greater than or equal to 30, which is classified as obese. When analyzing the various methods of weight loss, the exercise proved to be the most beneficial. This is felt to be due to the other changes that exercise induces in the body, in addition to burning extra calories. We know that greater muscle mass, as opposed to fat mass, burns more calories. It is also well known that visceral fat (which is stored within the abdominal cavity and is located near vital organs) secretes hormones that impact our appetites and the degree of inflammation. Exercise helps correct some of these hormonal changes.
An unfortunate finding, although not unexpected, was that once the intervention stopped, the participants regained weight. And they usually regained more weight than they had lost. This is something that people experience frequently — go on a diet to lose 10 pounds, stop the diet and then gain 15 pounds. This is of course due to the fact that diets are not sustainable. We have previously discussed that a 20% to 30% calorie reduction will lead to weight loss and actually may increase our longevity. We also discussed, however, that maintaining a 20% to 30% decrease in calorie intake is rarely possible. What is needed are lifestyle changes that are sustainable.
In the PLOS Medicine study, an unexpected finding was discovered in patients who were described as “lean”: that is, having a BMI of less than or equal to 25. Weight loss in this group of patients actually predicted more weight gain later in life AND an increased risk of developing diabetes. This finding is somewhat paradoxical, and the authors offer several hypotheses, but they indicate that more study is needed. It’s this finding, however, that led to the headline “Harvard scientists find weight loss is not always good.” What the headline does not specify is that the weight loss in those who did not need to lose weight would not confer the benefit that an obese person with a BMI greater than or equal to 30 would achieve. Please note, this study was observational, so the researchers were watching what the patients were doing and what patients were reporting.
My point in comparing the article to the actual study is to highlight the misleading, and perhaps sensational, headline. If my personal bias happened to be that I did not feel that weight loss for myself or others was important, reading only the headline would confirm that personal bias. But that, however, is not the gist of the article. This article, without qualification, does state that patients who are obese experienced benefits from weight loss. And this benefit, in terms of reducing the risk of diabetes, is seen even if the weight loss is only temporary.
A quick Google search of online articles on the topic reveals an estimated 70% to 80% of people read only the headlines. A study conducted by Columbia University and the French National Institute (Inria) found that in 59% of links shared on the Internet, the whole article was never accessed or read — only the headline was. This led me down a completely different path, reading the findings from the Columbia University study as well as articles discussing confirmation bias, information overload and human attention span. Apparently, the human attention span was 12 seconds in 2000, and in 2022 it is only 8 seconds. This is attributed in part to the unprecedented amount of information available on the Internet and our brain’s hard-wired desire for information. That really didn’t startle me, until I read further into the article and discovered the attention span of a goldfish is 9 seconds. There is an often-quoted study showing that physicians will only give a patient 18 seconds to answer a question. In light of the knowledge that we have less of an attention span than a goldfish, 18 seconds may not be so bad! (Yes, this is sarcasm!)
Headlines are made to be sensational and to capture our attention. The reasons for this have to do with advertising dollars (including for media organizations, which are often also businesses), clicks on a website, and other factors. It is our responsibility, as the public who is consuming this information, to actually read the article and at least attempt to gain an understanding of the implications of the knowledge.
The 18th-century poet and satirist Alexander Pope said it best: “A little learning is a dangerous thing.”
We Only Read The Headlines: But What’s The Real Story?
