clock menu more-arrow no yes mobile

Filed under:

Survey: Americans still believe diet pills work — they don't

Sean Gallup/Getty Images

Nearly a quarter of Americans have purchased weight-loss supplements, and more than a quarter of the pill users believe that they're safe and effective.

These findings come from a new Consumer Reports survey of 3,000 Americans that finally brings some much-needed data to the table on how people use diet pills and what they think about them.

The report revealed that, while there's widespread use of off-the-shelf weight-loss aids, there's just as much misinformation about them.

Here are some of key findings from the survey:

  • A quarter of respondents thought diet pills have fewer side effects than prescription drugs or over-the-counter medications.
  • Nearly 20 percent thought the diet pills are safer because they’re "natural."
  • About half of the supplement users reported experiencing at least one side effect, including a rapid heart rate, jitteriness, dry mouth, or digestive problems such as constipation or diarrhea.
  • A third of the supplement users didn’t lose any weight.
  • Another third lost some weight, and 9 percent reported losing all the weight they hoped they would.
  • 85 percent of those who reported weight loss from the supplements were also on a diet or exercise program so it's not clear the supplements had anything to do with the weight loss.
  • The majority of people who took these pills didn't inform their family doctors.

For evidence-based reading on how to lose weight, see the Vox series: Surprisingly simple tips from 20 experts about how to lose weight and keep it off,The right way to count calories, according to experts, Everything you wanted to know about weight loss and obesity

Nutrition supplements are very loosely regulated

Of course, supplements aren't regulated the same was as other pharmaceuticals and medical devices — a fact that escaped many of the survey respondents.

Manufacturers of these pills don't need to prove that they're safe and effective before going to market. Because they're not required to demonstrate that their products actually do what they are marketed for, these pills can be promoted for any number of health benefits with no real evidence backing the claims.

As Peieter Cohen — an internist and assistant professor at Harvard Medical School — showed in one of his studies, supplements may also contain chemicals and designer stimulants that have never been tested in humans.

What's more, there's no organized approach to collecting information about the adverse effects related to supplements, he said. "So the combination of no human trials before these products reach store shelves combined with fact we have no systematic way of detecting harm, it's like throwing a match into a forest during a drought."

There's growing evidence that supplements can be harmful

Liver damage and failure from diet pills has been a well-documented problem, Vox has reported. In one example, the Centers for Disease Control and Prevention found that the weight-loss supplement OxyElite Pro caused nearly 100 people in 16 states to develop hepatitis, leading to liver replacements, hospitalization, and even death.

The Federal Trade Commission has been waging war on weight-loss supplements, too, recently suing the makers of popular products such as green-coffee beans for misleading and harmful marketing practices.

Dr. Mehmet Oz, host of the popular Dr. Oz Show, regularly features weight-loss pills on-air, and was dragged before a senate sub-committee last summer to explain why. 

As Sen. Claire McCaskill summed up: "The scientific community is almost monolithic against you in terms of the efficacy of those three products that you called miracles."

Consumers need to proceed with caution

Until there's a more robust regulatory process in place, Cohen warned that buyers need to proceed with caution.

"This category of supplements is sold as if they're going to help you: supplements for weight loss, to improve workouts in the gym. They are often labelled as having tons of diff natural ingredients combined. But actually they might rely on one chemical to have this effect." And that chemical might be dangerous.

"No consumer product should kill you. With supplements, we accept it's okay to take these pills, even if they might lead to a heart attack or stroke. To me it's mind boggling that we accept this."

H/T Time magazine

Sign up for the newsletter Sign up for Vox Recommends

Get curated picks of the best Vox journalism to read, watch, and listen to every week, from our editors.