Final answer:
The statement that sugar decreases dopamine is incorrect; consumption of sugar usually leads to an increase in dopamine levels, giving a rewarding feeling that reinforces sugar consumption.
Step-by-step explanation:
The assertion that sugar decreases dopamine is not accurate. In fact, consuming sugar can lead to an increase in dopamine levels, which is why sugary foods are often perceived as rewarding and can contribute to the desire to eat them. Dopamine is a neurotransmitter that plays a key role in the reward and pleasure centers of the brain.
When you consume sugar, it can trigger the release of dopamine, reinforcing the action of eating sweet foods. This is particularly evident in studies on the effects of certain stimuli, such as nicotine, which increases dopamine levels in a manner similar to how sugar can affect dopamine release. The molecular similarity of sweeteners like stevia to glucose means they can activate the same taste receptors without raising blood sugar levels, which shows the complex interaction between sweeteners and the gustatory sense. However, substances like cocaine, which increase the presence of dopamine in the synaptic cleft and impair its reuptake, would be considered agonists since they enhance the action of this neurotransmitter, in contrast to the notion that sugar would decrease dopamine release.