Study on Saccharin and Weight Gain in Rats Is Illogical and Not Applicable to Humans

ATLANTA (February 20, 2012) — Findings presented in a study titled “Adverse Effects of High-Intensity Sweeteners on Energy Intake and Weight Control in Male and Obesity-Prone Female Rats” by Swithers et al.¹ should be interpreted with caution.  The study was conducted on a small number of rats and it is well known that humans and rodents metabolize substances differently.  According to Calorie Control Council President, Dr. Haley Stevens, “The study by Swithers et al is counter to numerous human studies that have shown that low-calorie sweeteners, including saccharin, may assist individuals in losing weight and/or maintaining weight loss.”

The Calorie Control Council cites the following as serious limitations of the study:

• The results of the study are illogical.  Rats who ate a yogurt supplement sweetened with saccharin only gained weight if they were also eating a high fat, high sugar diet.  The weight gain seen was likely from the high fat, high sugar diet, not the saccharin-sweetened yogurt.
• This study is counter to numerous human studies that have shown that low-calorie sweeteners may assist individuals in losing weight and/or maintaining weight loss.  In fact, a recent human study provided further evidence that replacing sugar-sweetened beverages with beverages sweetened with low-calorie sweeteners led to weight loss.²
• There are differences between rat and human bodily processes and it cannot be assumed that the reported results of this study would apply in humans.
• This study used less than 50 rats – too small a number to draw a statistically meaningful conclusion.  Furthermore, with such small numbers of subjects, if data from one rat markedly differs from that of the other rats, the overall findings could be skewed.
• The authors mislead readers by using inappropriate statistical analysis, likely creating- “false positives.”  When their initial experiments failed to show any significant results, the authors did “post hoc” analysis, often referred to as “data dredging.”  However, post hoc analysis is only appropriate to do once a significant association has been found in the original analysis.  Thus, the authors went searching for results after the study was complete, instead of testing a hypothesis with appropriate study design.
• Other factors may have influenced the findings.  Although authors controlled for many variables that could have affected the outcome of the study, some were not accounted for such as how many total calories the rats ate or how much of the yogurt supplement they consumed.

Robust scientific data stand in sharp contrast to the assertion that low-calorie sweeteners cause weight gain. Rather, research has demonstrated that low-calorie sweeteners can be useful tools for lowering and/or maintaining body weight – a critical issue in today’s environment of excess calorie intake and overweight. In fact, over a dozen human studies have shown that low calories sweeteners may assist individuals in losing weight and/or maintaining weight loss.

References

1. Swithers et al. Adverse Effects of High-Intensity Sweeteners on Energy Intake and Weight Control in Male and Obesity-Prone Female Rats. Behavioral Neuroscience. 2013.

2. Piernas et al. Does diet-beverage intake affect dietary consumption patterns? Results from the Choose Healthy Options Consciously Everyday (CHOICE) randomized clinical trial. American Journal of Clinical Nutrition. 2013