Artificial sweeteners are associated with both weight gain and weight loss and a counterintuitive effect on human physiology.
The adverse effects of sugar consumption, including type 2 diabetes and obesity, have driven the popularity of artificial sweeteners (eg, aspartame, sucralose) in the United States for many years. By one estimate, approximately 30% of adults and 15% of children aged 2 to 17 years reported consumption of low-calorie sweeteners between 2007 and 2008.1 In a counterintuitive trend, consumption of artificially sweetened beverages (ASB) and obesity have increased in parallel from 1962 to 2000, suggesting a possible causal relationship. A recent review of research on the topic in an opinion article in Trends in Endocrinology and Metabolism2 summarizes what is now known about the health effects of artificial sweeteners.
Author Susan E. Swithers of the Department of Psychological Sciences and Ingestive Behavior Research Center at Purdue University reviewed multiple key studies. The first prospective study, the San Antonio Heart Study, which followed men and women over a 7- to 8-year period, reported that the risk of weight gain and obesity was greater in those consuming ASB than in those who did not. The second prospective study followed two adolescent cohorts and found that artificial sweetener intake was associated with increased body mass index and body fat percentage.
An interventional study reported that normal weight children, aged 4 to 11 years, who consumed an ASB daily, gained less weight and fat mass compared with children who consumed sugar-sweetened beverages. Notably, however there was no comparison made to children who consumed unsweetened beverages. In the second interventional study, overweight adults who replaced sugar with artificial sweeteners had no increase in weight loss or improvement in fasting blood glucose.This suggests that artificially sweetened beverages may be linked with a lower risk of weight gain than sugar-sweetened beverages in normal weight individuals but not in overweight ones.
With respect to physiologic differences, it has been documented in human and animal studies that artificial sweeteners do not stimulate insulin release the same way or activate the same dopaminergic reward pathways in the brain as sugar does. Regular intake of artificial sweeteners therefore may, in fact, stimulate more sugar cravings.
Additional randomized trials and longer follow-up are needed to definitively establish whether regular consumption of these artificial sweeteners is safe and/or beneficial.
1. Sylvetsky, AC, Welsh JA, Brown RJ, Vos MB. Low calorie sweetener consumption is increasing in the United States. Am J Clin Nutr. 2012;96:640-646. (Abstract)
2. Swithers SE. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Trends Endocrinol Metabol. 2013; [Epub ahead of print] DOI:10.1016/j.tem.2013.05.005. (Full text)