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Bloomberg story on fiber benefits hinges on unpublished data from a private fitness app

Rating

4 Star

Categories

It’s Comical. It’s Critical. It Might Even Help You Lose Weight.

Our Review Summary

Box filled with harvested autumn applesThis story urges people to make sure they’re eating enough dietary fiber, with a focus on fiber’s role in promoting healthy weight loss. And, overall, it does a fairly good job — though giving a high-profile to unpublished data from a privately-owned fitness app (MyFitnessPal) is a little unusual.

To draw causal conclusions about a specific food/dietary component, without providing fulsome data is worrisome. Also, we’re unaware of any studies at this point that speak to the veracity of MyFitnessPal dietary record keeping, and the accuracy of its collection is probably worth validating and exploring–or at least noting its limitations.

And, on a broader level, focusing on a single ingredient such as “fiber” feeds nutritionism–the notion that the presence or absence of a particular nutrient makes a food healthful or not. We don’t have nutrition drilled down that specifically. This point would have made the story stronger.

 

Why This Matters

Fiber–especially from whole fruits and vegetables–is an important part of a healthy diet, with institutions from the Mayo Clinic to Harvard’s T.H. Chan School of Public Health outlining the myriad ways that a fiber-rich diet reduces health risks. And, as this story notes, most people don’t get enough fiber. Recommendations for daily intake of fiber vary, but tend to come in between 25 grams per day to 38 grams per day, depending on age and sex.

A 2014 paper from USDA’s Food Surveys Research Group found that Americans consume an average of 16 grams of fiber per day. Given the potential benefit of eating more fiber, this would seem like a conversation worth having. And that appears to be the goal of the story.

Criteria

Does the story adequately discuss the costs of the intervention?

Satisfactory

The story doesn’t specifically address costs, but it does discuss some of the most common types of fiber-rich food — such as fruits, vegetables, legumes and whole grains. Given the diversity, and widespread availability, of these foods, we’ll give this a Satisfactory rating. However, it would have been nice to see some acknowledgment that many people — people particularly people with limited financial resources — live in so-called “food deserts,” which have little access to fresh produce, etc.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Satisfactory

The story discusses a wide range of benefits, ranging from reduced risk of heart disease to weight loss. But the focus of the story was on weight loss, so that’s what we’ll focus on here. The story refers to two studies, only one of which appears to have been published. The first study is an analysis of people who have used the MyFitnessPal app in an attempt to lose weight. In that case, users who came within 5 percent of their weight loss goal consumed an average of 29 percent more fiber than users who did not come close to their weight loss goals. The second study was actually published (in 2015), and compared weight loss across two groups of study participants who had metabolic syndrome. One group followed the American Heart Association’s recommended diet, while the other was told only to eat 30 grams of fiber per day. Both groups ended up eating the same amount of fiber per day (19 grams), and both groups lost weight. At the end of a year, the AHA diet group lost more (an average of 5.6 pounds), but the second group still lost 4.6 pounds.

Neither of these studies are in the mold of a conventional intervention/health-benefit paradigm. But then neither is specifically looking at either a precisely-defined intervention (such as a pharmaceutical trial) or a disease — they’re looking loosely defined dietary guidelines and weight loss (and while weight can be a risk factor, it is not an illness). Bearing that in mind, the story does a satisfactory job of quantifying the relevant benefits in each instance.

Does the story adequately explain/quantify the harms of the intervention?

Satisfactory

In general, eating more fiber carries few potential harms. The primary risks are, as the Mayo Clinic notes, “adding too much fiber too quickly can promote intestinal gas, abdominal bloating and cramping.” To minimize that risk, the Mayo Clinic urges people to “Increase fiber in your diet gradually over a period of a few weeks. This allows the natural bacteria in your digestive system to adjust to the change. Also, drink plenty of water. Fiber works best when it absorbs water.”

This story does not outline these harms specifically, which is too bad. But the story does tell readers that they should “add fiber slowly and with plenty of water.” That’s enough to rate this as Satisfactory (though it’s clearly not ideal).

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The two studies, mentioned above under benefits, have some problems: It’s not clear where the unpublished MyFitnessPal data come from or how they were analyzed; and the 2015 study was of only 240 volunteers. These limitations were not noted.

Also, the story would have been much stronger if it had addressed one key question: Were there any differences between groups (in either study) in regard to their age, sex, or physical activity? Any of those factors could play a key role in differences in weight loss, and the story sheds no light there.

A side note: As we mentioned above, this story discusses a wide range of other benefits associated with eating enough fiber, ranging from reduced risk of heart disease to reduced risk of diabetes. We mention this because the story links to relevant research supporting each of those claims. We applaud that.

Does the story commit disease-mongering?

Satisfactory

There is no overt disease mongering. But we did want to point out two things. The story states: “fiber may play an important role in that ever-elusive health goal, weight loss.” First, while being obese may be a disease, simply being overweight is not. Second, many people who aspire to lose weight do so for reasons other than health (and aren’t overweight in the first place). Those are important distinctions, and ones that this story doesn’t make.

Does the story use independent sources and identify conflicts of interest?

Satisfactory

The story quotes from a wide variety of sources, and clearly labels each source’s affiliation.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

One issue that’s not addressed in the story is the utility of fiber supplements. Are they good? Bad? Beneficial? Useless? The story doesn’t offer any insight here. It would be useful for readers to know whether such supplements may be useful tools for meeting daily fiber intake goals.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

Foods that contain fiber have been around longer than humans have, so we’ll rate this N/A.

Does the story establish the true novelty of the approach?

Not Applicable

Dietary fiber isn’t new, and the story doesn’t claim that it is. We’ll rate this N/A.

Does the story appear to rely solely or largely on a news release?

Satisfactory

The story doesn’t appear to be based on a news release. (In fact, given that the story doesn’t seem to draw on any particularly new studies, guidelines or other external drivers, we’re kind of curious as to what spurred this story. We’re suspecting a pitch from MyFitnessPal.)

Total Score: 6 of 8 Satisfactory

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