Skipping breakfast before exercise might reduce how much we eat during the remainder of the day, according to a small but intriguing new study of fit young men.

The study finds that the choice to eat or omit a meal before an early workout could affect our relationship to food for the rest of the day, in complicated and sometimes unexpected ways.

Weight management is, of course, one of the great public — and private — health concerns of our time. But the role of exercise in helping people to maintain, lose or, in some instances, add pounds is problematic . Exercise burns calories, but in many past studies, people who begin a new exercise program do not lose as much weight as would be expected, because they often compensate for the energy used during exercise by eating more later or moving less.

These compensations, usually subtle and unintended, indicate that our brains are receiving internal communiqués detailing how much energy we used during that last workout and, in response, sending biological signals that increase hunger or reduce our urge to move. Our helpful brains do not wish us to sustain an energy deficit and starve.