That’s why the old school method of serving up your meal on a smaller plate, to trick your brain into eating less, is so dang popular. It’s based on the Delboeuf illusion, which posits that if you take two identical circles and put a large ring around one and a small ring around the other, the circle inside the small ring appears larger.
Unfortunately, new research has found that the Delboeuf inspired diet hack isn’t all it’s cracked up to be.
In a new study, published in the journal Appetite, participants were split into two groups – one was instructed to eat in the hour before the test and the other was directed not to eat for at least three hours before hand. They then had to view images of pizzas served on large and small trays, and hubcaps in large and small tyres, and identify the larger options in both examples.
They found that out the unfed group were more likely to correctly identify the larger pizza, regardless of the size of its tray. However, both groups were equally inaccurate when asked to compare the size of black circles and hubcaps placed within different sized circles.
Researchers say that this shows how hunger stimulates stronger analytic processing that can overcome the trickery of the illusion.
"Plate size doesn't matter as much as we think it does,” Dr. Tzvi Ganel, the study’s co author, said. “Even if you're hungry and haven't eaten, or are trying to cut back on portions, a serving looks similar whether it fills a smaller plate or is surrounded by empty space on a larger one."