Eating the same foods, day after day, may make you so uninterested in your meals that you start eating less, a new study suggests.
Women who ate macaroni and cheese every day for a week were taking in 100 fewer calories each day than normal by the week's end, the study showed.
The study "provides a very interesting new piece to the obesity puzzle by suggesting that meal monotony may actually lead to reduced calorie consumption," said Shelley McGuire, an associate professor of nutrition at Washington State University and a spokesperson for the American Society for Nutrition. "The trick will be balancing this concept with the importance of variety to good nutrition."
The study is published in the August issue of The American Journal of Clinical Nutrition.
A craving for variety
Similar to the way that drug addicts develop a need to increase their dose to feel the same effects, studies have shown that we become habituated to the foods that we eat often, said McGuire, who was not involved with the study. However, it was not known whether this would lead to an actual decrease in the calories we eat, nor was it known how often we have to eat the same thing to become habituated to it.
The 32 women in the study participated in half-hour long sessions in which they were given a computer task, and were rewarded with a serving of macaroni and cheese each time they completed their task. All of the women completed five of such sessions over the study's course, but half of the women participated in one session every day for five consecutive days, while the other half participated once a week for five weeks.
In contrast to the decrease in daily calories eaten by the women who ate the mac and cheese every day, the women whose sessions were spaced one week apart were eating about 30 more calories each day by the study's end.
This finding shows that eating the same food daily makes us habituated to it, whereas eating it weekly does not, the researchers said.
The researchers also looked at the effects of obesity on habituation — it has previously been proposed that obese people may take longer to develop habituation to foods, they said. However, the new study showed no difference in how long it took obese participants to become habituated to the macaroni in comparison with how long it took the non-obese women.
The researchers concluded that reducing variety in food choices could be an important strategy for those trying to lose weight.
The modern grocery store
Previous research has shown that increased variety in the diet is associated with greater body weight and poor choice of foods, the researchers wrote.
However, it remains unknown, the researchers said, how similar foods have to be to each other to produce the habituation effect. For example, they wrote, "Will someone show long-term habituation to consecutive meals of cheese pizza, pepperoni pizza and mushroom pizza?"
In any case, because habituation relies on a person to remember previous meals, deliberately recalling a recent meal may shorten the time needed to become habituated to a particular food, they said.
Pass it on: Eating the same food every day may become boring enough to make you eat less.
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