Which of the following is NOT a cause of fatigue?

In the context of fatigue, increased energy intake does not contribute to fatigue and can actually help restore energy levels in the body. The body typically requires a certain amount of energy to function effectively, and when energy intake is sufficient, it can replenish glycogen stores, support metabolic processes, and maintain overall performance. This can help prevent feelings of fatigue, especially during extended physical activity or exercise.

In contrast, glycogen depletion, central nervous system (CNS) fatigue, and the accumulation of metabolites are recognized as factors that can lead to fatigue. Glycogen depletion occurs when the body's carbohydrate stores are used up, which can happen during prolonged exercise, resulting in decreased energy availability. CNS fatigue involves a reduction in the central nervous system’s ability to generate signals for muscle contractions, which can be influenced by physical exertion and mental stress. The accumulation of metabolites, such as lactic acid, can also contribute to feelings of fatigue by affecting muscle function and performance.

Therefore, increased energy intake stands out as the factor that does not induce fatigue, making it the correct choice in this context.