Reduce Overeating After Mentally Taxing Work

The University of Alabama study asked students to complete a challenging exam, then either exercise or rest for 15 minutes. Researchers then treated the students to an all-you-can-eat pizza lunch.

In a separate session, the students also rested and then ate pizza to allow the researchers to get a baseline for the students’ appetite.

You might have thought the exercisers would be hungrier, but the opposite was true: those who had relaxed after the exam ate about 400 kilojoules more than their baseline.

In contrast, those who exercised ate about 100 kilojoules less than their baseline, plus they burned kilojoules during their 15 minutes of high-intensity interval training, reducing their overall energy intake even further.

Researchers say the lactate — one of the brain’s energy sources — that is produced during strenuous activity might have been enough to replenish the students’ brain energy needs after the exam, reducing their need to overeat.

The study has clear implications for the workforce and students, lead author William Neumeier said.

“The modern work environment is highly sedentary and cognitively demanding,” he said.

“Previous studies have shown that mentally demanding tasks, such as a big test, deadlines or other mentally strenuous tasks we perform every day, affect the brain’s energy demands, and increases in food intake were observed following such tasks.”

He said further research was needed to fully understand the observed effect exercise had on participants’ energy intake following mental work.