To date, adequately powered studies have not been conducted to evaluate the effect of aspartame on preference for sweet taste. 

The 2009 update did not find new studies meeting the inclusion criteria for this question and the 2009 N&NNS Workgroup  concurs with the conclusion above formulated by the 2008 Aspartame Workgroup. .

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.