Losing weight through exercise appears to be more difficult for obese people, research suggests.
Initially, the researchers thought that the total energy we expend in a day is the sum of the energy expended due to activity (from light gardening to running a marathon) and the energy used for basic functioning (which keeps us active even when we do nothing, such as immune function and wound healing).
But preliminary lab research indicates that simple addition could be misleading: Estimates of total daily spending tend to be less than the sum of baseline and activity spending for individuals.
To explore this further, a group of international scientists analyzed the energy expenditure measurements of 1,754 adults from a data set collected over decades and supplied by the International Atomic Energy Agency.
They found that increased activity levels with more exercise, for example, led each person’s body to compensate by limiting the energy expended on basic metabolic functions over a longer period, according to the study published in the journal Current Biology.
For example, if you go for a run and your activity tracker says that you burned 300 calories (and didn’t eat differently), you can assume that your total daily energy expenditure increased by 300 calories.
That may be the case in the short term, but in the long term, the body begins to compensate for this additional energy effort by reducing the energy expended in other processes, said lead author Professor Lewis Halsey of the University of Roehampton.
“It’s as if the government is trying to balance the budget: if, for example, it spends more on education, it may have to spend less on roads,” he said.
This can also be seen in people trying to lose weight; At first, they may find that they lose some weight, but over the course of weeks and months, that loss is irritatingly stagnant, and part of the reason could be that your body is consuming less energy for basic function.
Overall, the analysis showed that in people with the highest BMI (body mass index), about half of the calories burned in activity is translated into calories burned at the end of the day, while in those with a normal BMI , approximately 72% of the calories burned during the activity were reflected in the total daily energy expenditure.
“There seems to be … a higher energy compensation in people with a higher BMI,” Halsey said, cautioning that it was not clear why.
“Are these people heavier, in part, because they offset more energy, or do they offset more energy once they weigh more? We do not know “.
Resolving questions about the causality of the relationship between energy compensation and body fat accumulation will be key in shaping and improving public health strategies regarding obesity, the researchers noted.
It’s also unclear how much of the body’s basic function is lost to compensate for the extra activity, Halsey noted.
Still, exercise is still a healthy thing, in addition to trying to burn calories.
“And if we try too hard to burn a lot of calories by constantly increasing our exercise,” he said, “we could get into a little trouble because as our bodies compensate more and more … we could start to see the damaging effects.”
George is Digismak’s reported cum editor with 13 years of experience in Journalism