Anyone who’s ever tried to lose weight by upping their workout regimen can tell you that it’s a struggle. But why? If you keep your diet the same and hit the treadmill to burn an extra 500 calories a day you should start shedding pounds. It’s just math, right?
This traditional model, called the Additive Model, measures your total energy expenditure as the sum of how much energy you expend exercising and how much energy your body spends doing the everyday tasks that keep you alive, like cell repair.
But a newer model, called the Constrained Model, takes a different approach. Instead of tacking on additional energy spent exercising to the total, the Constrained Model says your body has a more limited amount of energy it can burn each day. Under this model, your body compensates by spending less energy on the tasks that keep you alive after exercising.
Read more: “Running Is Always Blind”
So which model is right?
To investigate, researchers from Duke University analyzed data from 14 different studies involving 450 people who participated in exercise programs, publishing their findings in Current Biology. By comparing the energy the participants were expected to burn with the amount of energy they actually burned, they were able to come up with a rough estimate of how much our bodies compensate for exercise.
They found that, on average, only 72 percent of the calories burned during exercise are added to total daily burn, with the remaining 28 percent compensated for by our bodies.
However, the researchers stressed that even though there wasn’t a one-to-one increase in calories burned, exercise still showed an overall boost in total calories burned. Moreover, the 28-percent compensation figure is only an average; some bodies may compensate more and some less.
In other words, don’t cancel your gym membership just yet.
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This story was originally featured on Nautilus.