Neonatal overfeeding induced by reducing the litter size leads to an obese phenotype and increases preference for sweet food in adult male rats.

Early overfeeding can change food preference without increasing every kind of intake

This experiment asked whether excess nutrition soon after birth affects the foods animals later choose, alongside its effects on body weight. The distinction matters because eating more of a preferred food is different from eating more of everything.

A model of early overfeeding. Researchers raised male rats in litters of four or eight, reducing competition for milk in the smaller litters. They studied 55 offspring from eighteen litters and later measured body weight, abdominal fat, food intake, movement and anxiety-related behavior.

Preference emerged when there was a choice. Rats from smaller litters were heavier and carried more abdominal fat. When standard chow or sweet food was tested separately, the groups did not differ significantly in intake. When both foods were offered together, however, the early-overfed animals ate more sweet food than controls. The choice test therefore detected a difference that the separate intake tests had missed.

The groups did not differ in general locomotor activity, while the smaller-litter group showed reduced anxiety-like behavior on the test used. Those observations help characterize the model and discourage treating increased sweet preference as interchangeable with increased anxiety or reduced movement.

The study connects an early nutritional manipulation with adult body composition and relative food preference. It does not identify the brain mechanism behind that preference. Its contribution is to show that the later effects of early overfeeding depend partly on what is measured: ordinary intake, intake of a single palatable food, and choice between foods can yield different answers.