Dr. Birch joined the faculty of the University of Illinois, Urbana-Champaign, in 1976. She taught both human development and nutritional sciences, an indication of the cross-disciplinary approach that would characterize her research. In 1992 she moved to Penn State, where she would eventually direct the Center for Childhood Obesity Research. In 2014 she joined the University of Georgia faculty.
The findings coming out of her labs made news repeatedly over the years. One was that coercing a child to eat, say, a vegetable by dangling the prospect of dessert was a bad idea.
“The universal parental tactic of offering children a reward if they finish a certain food — you can have some cake if you finish your peas — might work in the short term,” she told The New York Times in 1989. “But in the long run, it makes children dislike the food they had to finish.”
Also unsound, she said, was the old finish-everything maxim; a better approach was to encourage children to follow their own hunger signals.
“If you focus on external factors, like how much food is left on the plate, or what time it is, then children get out of touch with their internal cues for when they are hungry and when they are full,” she said.
Those cues, her research showed, were pretty reliable if left on their own; one study found that though a child might eat 100 calories at breakfast one day and 350 the next, the overall calorie intake for the day tended to be consistent.
“If your parents say it’s not time to eat yet when you tell them you’re hungry, or insist you finish what’s on your plate when you’re already full, it can lead you to look to externals to decide when and how much to eat, and that creates lifelong weight problems,” Dr. Birch said. “Natural eaters, in contrast, eat when they’re hungry and stop when they’re full. They rarely have weight problems.”