Unfortunately, it is not possible to avoid the harms of too much sugar by replacing it with an artificial sweetener – especially not aspartame. While producers of this sugar substitute swear that it is safe, several studies have linked aspartame to behavioral and cognitive problems. As a chemical stressor, it can cause deleterious effects on the ability to learn and regulate emotions.
In one study, just 8 days of a high-aspartame diet cause participants to score lower on mental tests and feel more irritable and depressed to boot. Another study revealed that people who drink a lot of diet soft drinks, which replace the sugar with artificial sweetener, have an increased risk of dementia or stroke. For now, the FDA says aspartame is safe, but also mandates warning labels on products that contain it.