November 19/Porto Alegre, Brazil/Federal University do Rio Grande do Sul -- A new study suggests that saccharin and aspartame cause a greater weight gain than sugar, even with the same intake of calories.

The study was led by Fernanda de Matos Feijóa of the Faculty of Medicine of the Federal University do Rio Grande do Sul, Ramiro Barcelos in Porto Alegre, Brazil.

Researchers gave rats plain yogurt sweetened with aspartame, saccharin, or sugar, plus their regular diet, for 12 weeks. Rats that ate the aspartame- or saccharin-sweetened yogurt gained more weight than those on the sugar-sweetened yogurt, despite all the groups ingesting a similar amount of calories. Researchers think the artificial sweeteners caused a decrease in energy used, or caused fluid retention. The study was published in the journal Appetite.

Previous research on humans shows that aspartame increases appetite and that many artificial sweeteners increase the motivation to eat. Sweet tastes from artificial sweeteners without calories could lead to greater ingestion of calories.