In the study, rats were divided into groups, some eating a high-fat diet, others a low-fat diet. Those on the high-fat diet were further divided into two groups. One group was given, in addition to its regular chow, Pringles chips that were high in fat and calories. The other half of the high-fat-diet group was given full-calorie Pringles some days and low-calorie Pringles other days. Those low-calorie chips contained olestra, a calorie-free fat substitute.

The rats that alternated between the full-fat and olestra-containing chips ate more food overall, gained more weight and grew more fatty tissue than did the rats that ate only full-fat, higher-calorie chips.

Rats and humans have similar biological responses to food, the study notes.

The idea that eating foods made with fat substitutes instead of real fat can aid weight loss has fueled some food manufacturers’ efforts to provide such foods in recent years. That phenomenon runs parallel to the idea that eating foods made with artificial sweeteners can keep weight in check. The same research team that conducted this new rats/fats study had done research, with similar findings, into rats’ reactions to artificial sweeteners. In short, they found, eating foods sweetened with saccharin and the like can lead to weight gain and boost body fat.

Both lines of research hint that the body may, when anticipating fatty or sweet foods, get primed for a big dose of calories. When those calories are not delivered, the body feels cheated and compensates by overeating, trying to achieve the sensation it expected to get from eating the delicious, high-calorie food it expected in the first place.

The researchers note that the use of fat substitutes and artificial sweeteners roughly coincides with the rise in overweight and obesity among Americans over the past 30 years.

From the June 21, 2011, Prepared Foods' Daily News.