Turns out, she was right.
New research suggests eating those smaller bites may trick your brain into thinking your full faster.
Researchers gave over 300 college students either a full bagel, or one that was cut into four pieces.
Those students were later given a free lunch. The students who had the bagel cut into pieces ate 25% less of their lunch.
Experts say eating four pieces may have tricked their brains into thinking they had more food, while a full bagel is seen as a single portion. The researchers say cutting your food into small pieces may be a new dieting tactic.