Is low fat making you fat? The problem with fat replacements

Researchers at Purdue University recommend that people who want to lose weight might also want to lose the fat substitutes - like Olestra - from their diets

In the study, rats were given either regular full fat crisps or a fat-free version made with Olestra - a calorie-free synthetic fat.

Surprisingly, the rats who ate fat-free were in a for a surprise on weigh-in day.  "They actually ended up gaining more weight,” said the head of the study, Purdue Professor of Psychological Sciences Susan Swithers.

She suggests that weight gain happens because these substitutes confuse the body... and its ability to estimate how many calories are taken in. This directly impacts your body's notion of appetite and its ability to regulate intakes.
She explains:"After an experience with Olestra, that cue no longer predicts a lot of calories all the time so we might over eat the next time we get fat that has calories."

Rather than choose low fat, she suggests that "reducing portion sizes and paying attention to how many calories we're consuming is a better way to go.”