Getting a bag of leftover dog food can reduce food waste, but it can derail your diet and exercise goals, according to a new study.
Many dieters try to keep fit by eating only some of their food, saving the rest for later.
However, marketing researchers at the University of Michigan have found that this often leaves people with the false impression that they "eat less," which means they are "rewarded" with extra food or skipping the gym.
This problem is becoming increasingly worrying as portion sizes grow, and those who "just eat half" of their food continue to consume a lot of calories.
"We know that increasing portion sizes increase consumption, but excessively expanded portions also cause consumers to face more leftovers," said Aradhna Krishna, a marketing professor at the Ross Business School at the University of Michigan. .
Krishna and co-author Linda Hagen of the University of Southern California conducted five studies to see how leftovers can bias our perception of our own eating habits.
In general, no matter how much food someone ate in their first session, if the portion left over was large, they seemed to think they had not eaten too much.
That misconception had a direct effect on a person's lifestyle in the hours and days that followed.
People with larger debris were more likely to indulge in unhealthy snacks and larger portions in the meals that followed, because they felt they had been "won."
In the same sense, a person with a large portion left over felt less motivated to exercise than someone who left nothing, even if the two ate the same.
"The psychological factors of this phenomenon are two," said Hagen.
& # 39; Larger leftovers reduce perceived consumption, which leads people to feel better about themselves. And feeling better about themselves, in turn, reduces people's motivation to compensate. "
The United States has always been known for giving its rotund population more for its money, and more and more.
In the last 25 years, the average serving size in any given establishment has doubled or tripled.
Bagels are now six inches wide, not three; a medium bag of popcorn is 11 cups, not five; and a soft drink is 20 ounces, not 6.5.
Americans are not necessarily eating more in an environment. A study by other researchers found that when serving sizes increase by 100 percent, people only eat 35 percent more.
However, that means that their leftover portions are growing, and Krishna and Hagen warn that it also affects us.
"This study demonstrates that even leftovers derived from these expanded portions can affect consumption later, broadening the scope of portion size research and highlighting the complex ways in which enlarged portions can influence consumption behaviors," said Krishna. .
"Our research reveals that uneaten foods can have a significant influence on perceptions, affect, motivation and important behavior related to people's health."