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Large study links use of artificial sweeteners to gaining — not losing — weight

What makes this study, conducted by the Canadian Medical Association Journal, more authoritative than past ones is that it is a systematic review.

Researchers warn that people should use artificial sweeteners with caution until more is learned about their effects on the human body.

Yet another study has uncovered evidence that artificial sweeteners do not help people lose weight.  

In fact, the study, published Monday in the Canadian Medical Association Journal, reports that artificial sweeteners may actually hamper efforts to shed excess pounds. For it found that people who regularly consume artificial sweeteners — products such as aspartame, sucralose and stevia — are more likely to gain weight.

They’re also more likely to develop diabetes and cardiovascular disease, the study found.

What makes this study more authoritative than past ones is that it is a systematic review. Its authors analyzed the findings from more than three dozen other studies on the topic, including many randomized controlled trials, which are considered the most rigorous form of clinical research. 

“Given the widespread and increasing use of artificial sweeteners, and the current epidemic of obesity and related disease, more research is needed to determine the long-term risks and benefits of these products,” said Meghan Azard, the study’s lead author and an assistant professor of health sciences at the University of Manitoba, in a released statement.

Past findings have been mixed

As background research in the study points out, at least 30 percent of American adults consume foods or beverages with artificial sweeteners every day — a percentage that is increasing. Most people turn to no-calorie or low-calorie sweeteners because they believe the products will help them maintain a healthier weight.

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But studies investigating the effect of artificial sweeteners on weight have produced mixed results. Some studies have reported that the products are associated with modest weight loss, but others have found an association with weight gain. 

Furthermore, recent research has suggested that artificial sweeteners may have adverse effects on how the body metabolizes sugar, on the composition of gut bacteria and on appetite control.

Taking a new look

For their review, Azard and her colleagues analyzed data from 37 different studies. Seven of the studies were randomized controlled trials that followed about 1,000 people for an average of six months. The others were observational studies that tracked about 400,000 people for an average of 10 years.

The randomized trials showed artificial sweeteners had no consistent effect on body mass index (BMI), while the longer observational studies found that consumption of artificial sweeteners was associated with a modest increase in BMI. The observational studies also found that the consumption of artificial sweeteners was linked to increases in weight and abdominal fat, as well as to a higher risk of developing obesity, high blood pressure, type 2 diabetes, heart disease and other health problems.

For example, people who consumed the most artificial sweeteners had a 14 percent higher chance of developing type 2 diabetes and a 32 percent higher likelihood of developing a heart-related problem compared to those who consumed the least. They were also 84 percent more likely to be overweight.

Of course, observational studies can show only an association between two things, not direct evidence that one thing causes the other. Other factors — ones not identified in the study — might explain the links between the consumption of artificial sweeteners and the higher risk of certain medical conditions.

Use with caution

Still the findings are troubling, particularly given the ubiquitousness of artificial sweeteners in the typical American diet — and the growing obesity epidemic.

“Despite the fact that millions of individuals routinely consume artificial sweeteners, relatively few patients have been included in clinical trials of these products,” said Dr. Ryan Zarychanski, a co-author of the study and a clinical scientist at the University of Manitoba, in the press release. “We found that data from clinical trials do not clearly support the intended benefits of artificial sweeteners for weight management.”

The researchers warn that people should use artificial sweeteners with caution until more is learned about their effects on the human body.

For more information: You can read the study in full on the website of the Canadian Medical Association Journal.