In a study of Olestra, the fat substitute recently approved for
human consumption by the FDA, researchers from Pennsylvania State
University concluded that human taste buds apparently don't detect
the difference between the low-calorie fat replacer and regular
fat when used in potato chips.
"This is important because it suggests that if we can get
the taste and texture of fat-free and reduced-calorie foods right,
then they can be just as satisfying to our sense of taste and
texture as the regular version of that food, despite being lower
in fat and calories," said nutrition researcher Debra Miller
of Penn State's University Park campus, who reported the findings
at Experimental Biology '96, an annual meeting of biologic and
Miller and her colleagues also found no difference in how fast
people's taste for the two types of chips diminished, suggesting
that neither fat nor calories provide sensory signals to taste
buds that cause people to grow tired of a specific food. "If
fat and calorie content are important to achieving sensory-specific
satiety, then we would have expected different results from the
two types of chips," Ms. Miller said.
The study--involving what Penn State's Barbara J. Rolls, phd,
labeled the fat substitute most systematically investigated--provides
additional evidence that humans find olestra agreeable to their
palates and their stomachs.
Need for Real-Life Evidence
But as Dr. Rolls, Ms. Miller's coauthor, noted separately in a
press conference, a great gulf separates the impressive support
built up for Olestra and other fat substitutes in the laboratory
and what might happen in the real world.
"There is really no evidence at all on how these products
affect people in real life situations," Dr. Rolls said. "Ultimately,
we need to know how the whole array of fat-substituted foods impact
people's diets, both in terms of energy intake and the macronutrient
composition, and if they're having an impact on body weight. It
isn't an easy study. The kinds of ways people incorporate these
foods into their diet isn't known at all."
Effects on Children Still Sketchy
Questions remain, as well, about the effects of fat substitutes
on children, particularly young ones. A short-term study reported
3 years ago by Leann L. Birch, phd, head of Penn State's College
of Health and Human Development, used Olestra in addressing the
issue of whether children compensate for the calories eliminated
from their diet with the use of fat replacers by eating more food,
or if they actually have a reduction in total energy intake, which
could cause developmental problems.
"Calories were essentially the same," Dr. Birch said,
adding that the work she and her colleagues did was the only attempt
she knew of to resolve the question.
A variety of fat replacements exist, including carbohydrate-based
dextrins, modified food starches, polydextrose, and gums. Others
include in their formulation monoglycerides or triglycerides.
Olestra, formed by the esterification of sucrose with fatty acids
from edible oils, can be used in cooking, baking, and, unlike
other fat replacements, frying. Despite its sucrose lineage, the
product lacks sweetness and looks, tastes, and feels like fat.
The FDA granted Procter & Gamble approval in January to market
olestra for use in savory snack foods, such as cheese curls and
potato and corn chips. Products fried in olestra, which P &
G is selling under the brand name Olean, have recently entered
three small test markets.
No Miracles Expected
No one should expect weight-wasting miracles from olestra or other
fat replacers, advised John C. Peters, phd, Procter & Gamble's
associate director for regulatory and clinical development, food
and beverage products. "People expect these things to make
people who are obese melt away and turn into nice, skinny people.
That's generally not going to happen."
Fat replacers can only help people control or lose weight if they
are part of a sensible diet, he stressed. "As someone said,
this is a replacement for fat, not for common sense."
More than a dozen studies have addressed whether when fat is replaced
with olestra people "make up that fat by eating other fatty
food, so that they get the same amount of fat at the end of the
day," Dr. Peters said. "The answer across the board
is that there is no fat-specific appetite. So if you take the
energy out by taking the fat out, people might make up some of
the energy, they might even make up all of the energy, but they
don't make up the fat. So you get the fat-reduction benefit."
Thin people who didn't need to cut calories maintained their same
level of calories in some studies with olestra, but all still
cut their fat intake.
However, the laboratory is not the lunch room. People can override
the weight-control and/or reduced fat benefits of fat reducers
by eating more of low-fat foods or by eating other fatty foods.
"Clearly, if people take things into their own hands, what
I call cognitive override, they can do anything they want,"
Dr. Peters said. "What they do in their head, we will have