Do diet foods make kids fat?

The research was conducted on laboratory rats.

TORONTO GLOBE AND MAIL

Feeding children diet food and low-calorie drinks may, paradoxically, spur overeating and weight gain, a new Canadian study suggests.

That’s because humans, like most animals, are able to instinctively match calorie intake with the body’s needs, and are conditioned to associate food tastes with calories ingested.

But when children ingest diet or caloriewise versions of foods normally high in calories, this can distort these important connections between taste and caloric content and lead to overeating, according to the research.

“Essentially, they are tricked or fooled by the taste, and conditioned to think it will always be low in calories,” said David Pierce, a sociologist at the University of Alberta in Edmonton.

He is also the lead author of the study, published in Wednesday’s edition of the journal Obesity.

The research was conducted on laboratory rats. However, Pierce said it is probably applicable to people because the “taste-conditioning process” is identical in rodents and humans.

He said the message for parents is straightforward: Feed children a healthy, well-balanced diet with sufficient calories to meet their energy needs. That way their bodies will be able to use taste-related cues to assess the energy value of their food correctly.

To conduct the study, researchers carried out a series of elaborate experiments. Young rats were given sweet or salty Jell-O-like cubes that either contained high-calorie starch or were artificially sweetened and contained no starch. This was done to condition tastes.

Later, the rats were fed snacks, then regular meals, and food consumption was measured. Those who associated the taste of “diet” snacks with fewer calories routinely overate at meals.

The same experiment was conducted with lab rats that were bred to be lean or obese, with the same results. However, the additional calories (and weight gain) were more detrimental to the obese rats.

That suggests that kids prone to obesity for genetic or other reasons will be worse off in the long run if they consume diet foods in their formative years.