Cutting calories, portion sizes may really work

By Amy Norton

NEW YORK (Reuters Health) – Though countless fad diets
promise a trimmer physique, the old-fashioned route of portion
control and calorie consciousness may be the way to go after
all, a new study suggests.

In an experiment with 24 young women, researchers found
that the study participants ate far fewer daily calories when
their meal portions were trimmed down or when they traded in
some calorie-dense dishes for less rich substitutes — all
without their feeling deprived.

Both diet tactics — portion control and lower-calorie
options — were effective and “additive,” meaning women took in
the fewest calories when they practiced both, the study found.

In fact, the two together sliced a whopping 812 calories,
on average, from the women’s daily intake, according to
findings published in the American Journal of Clinical
Nutrition.

What’s exciting about the results, lead study author Dr.
Barbara J. Rolls told Reuters Health, is that the calorie
plummet came without “huge changes” to the diet, and without
leaving the women feeling hungry at the end of the day.

The diners still enjoyed brownies, potato chips and cheese
and crackers, albeit lower-fat versions.

It’s thought that life in a land of plenty — especially
cheap, super-size portions of calorie-dense foods — is fueling
the rise of obesity in the U.S. and other nations. Calorie
density refers to a food’s number of calories pound for pound.
A pound of broccoli, for instance, has far fewer calories than
a pound of chocolate.

Past research has shown that portion size can play a vital
role in a person’s calorie intake; if there’s more food on the
plate, more food goes into the stomach — even if the diner
could feel satisfied with less.

But calorie-density is also key, according to Rolls, a
professor of nutritional sciences at Pennsylvania State
University in University Park.

And, in fact, cutting calorie density without cutting
portions was more effective in this study than simple portion
control.

The 24 women, who ranged in age from 19 to 35, followed
each of four menu plans for two days apiece. One plan had them
eating standard portions of common foods like muffins, pizza,
pasta and salad. Another gave them lower-calorie versions of
these same meals — reduced-fat snack food, for example, or
dinners containing a larger proportion of vegetables.

A third eating plan gave the women full-calorie fare but
smaller servings, while the fourth included both portion
control and lower-calorie foods.

The researchers found that all three of the diet-conscious
tactics cut the number of calories the women ate each day, but
the combination of portion control and calorie-watching was
most effective, lowering their calorie intake by 812 calories a
day.

Controlling calorie density was, however, more effective
than eating smaller servings of richer foods. The former cut an
average of 575 calories from the women’s daily intake, while
portion control trimmed their daily calories by 231.

Rolls said the “message” here for restaurants is that
lowering the calorie density of their meals, and less so the
size, may be the wiser move. Customers may feel cheated by the
sight of skimpier servings, she noted, but may not notice the
lower calorie density.

At home, Rolls said, people can trim the calorie density of
their meals by adding more vegetables to the plate, or by
having a light soup or large salad as a starter.

SOURCE: American Journal of Clinical Nutrition, January
2006.