Learning to make healthy choices can counter the effects of large portions

January 25, 2018 by Katie Bohn, Pennsylvania State University
Credit: CC0 Public Domain

People are often told that eating everything in moderation can help them lose weight, but it is better to choose healthier foods than to try to eat less, according to Penn State researchers.

In a recent study, measured how much participants ate when given meals that varied in portion size. Despite about one-third of participants having been trained in different strategies to manage portions during a previous year-long weight loss trial, all participants ate more as portion sizes grew. Although the trained participants ate the same amount as the others, they tended to choose and ended up consuming fewer calories overall.

"The results show that choosing healthy, lower-calorie-dense foods was more effective and more sustainable than just trying to resist large portions of higher calorie options," said Faris Zuraikat, graduate student. "If you choose high-calorie-dense foods but restrict the amount that you're eating, portions will be too small, and you're likely to get hungry."

Previous research has shown the power of the "portion size effect," which is the tendency for people to eat more when larger portions are served and can result in people consuming more calories than they intended.

The researchers designed an intervention to help people counteract this effect, in which participants were taught strategies to control food portions and eat healthier. Zuraikat said he and the other researchers wanted to see if this training was effective in helping people control portions.

"We gathered a group of subjects who had extensive training on portion-control strategies to see if their response to increasing portion size of foods served at a meal differed from untrained individuals," Zuraikat said. "We were also interested in whether those untrained individuals with overweight and obesity or normal weight differed in their response."

The researchers recruited three groups of women to participate in the study: 34 controls with overweight, 29 controls with normal weight, and 39 who had previously completed a one-year weight loss trial emphasizing portion-control strategies. All participants visited the lab once a week for four weeks. During each visit, the researchers provided the same foods but increased the portion size of the foods in a randomized order across weeks.

Each meal consisted of foods with higher calorie density, like garlic bread, and lower calorie density, like salad. Foods were weighed before and after the meal to determine how much was eaten, and was determined from these measures.

The researchers found that when they were given larger , participants in all three groups ate more. For example, when the portion size was increased 75 percent, the average amount consumed went up 27 percent.

However, the participants who received training consumed fewer calories overall than those who did not. Even though the participants in all three groups ate similar amounts of food, the participants who received training chose foods lower in calorie density.

"All the groups were served the same meals, but their food choices differed. The participants who went through the training consumed more of the lower calorie-dense foods and less of the higher calorie-dense foods than the untrained controls," Zuraikat said. "Consequently, trained ' calorie intake was less than that of the control groups, whose intake didn't differ by weight status."

The researchers say the study—published in the journal Appetite—illustrates the strength of the effect while also suggesting easier, more sustainable strategies for managing calorie intake.

"The study supports the idea that eating less of the higher-calorie-dense foods and more of the nutritious, lower-calorie-dense foods can help to manage hunger while consuming fewer calories," said Barbara Rolls, professor and the Helen A. Guthrie Chair of Nutritional Sciences, Penn State. "You still have a full plate, but you're changing the proportions of the different types of foods."

Explore further: Keep an eye on children's calories, researchers say

More information: Faris M. Zuraikat et al, Comparing the portion size effect in women with and without extended training in portion control: A follow-up to the Portion-Control Strategies Trial, Appetite (2018). DOI: 10.1016/j.appet.2018.01.012

Related Stories

Keep an eye on children's calories, researchers say

March 17, 2016
Most children overeat significantly when served large portions of calorie-dense popular foods, according to a Penn State study. The results suggest that manipulating calorie content and portion size can substantially reduce ...

Readjusting calorie consumption as you lose weight

January 12, 2018
(HealthDay)—If you find that your weekly weight loss is slowing down, maybe it's time to readjust your calorie intake.

Be sure to read labels for portion, calorie control

January 11, 2018
(HealthDay)—"Nutrition Facts" labels mandated by the U.S. Food and Drug Administration have made it easier to know more about what's inside packaged foods. But the information isn't always easy to decipher, especially since ...

New research finds brain activation in children viewing large portions of food

December 15, 2016
Viewing large portions of high-calorie food activates reward and sensory processing areas in children's brains, according to a Penn State study.

How dieting encourages your body to replace lost weight

August 3, 2017
Obesity is a risk factor for numerous disorders that afflict the human race, so understanding how to maintain a healthy body weight is one of the most urgent issues facing society. By 2025, it is estimated that 18 percent ...

Recommended for you

Students more likely to eat school breakfast when given extra time, new study finds

August 18, 2018
Primary school students are more likely to eat a nutritional breakfast when given 10 extra minutes to do so, according to a new study by researchers at Virginia Tech and Georgia Southern University.

Like shark attack and the lottery, unconscious bias influences cancer screening

August 17, 2018
What do shark attack, the lottery and ovarian cancer screening having in common? It turns out our judgments about these things are all influenced by unconscious bias.

Moderate carbohydrate intake may be best for health

August 17, 2018
Eating carbohydrates in moderation seems to be optimal for health and longevity, suggests new research published in The Lancet Public Health journal.

Phantom odors: One American in 15 smells odors that aren't there, study finds

August 16, 2018
Imagine the foul smell of an ash tray or burning hair. Now imagine if these kinds of smells were present in your life, but without a source. A new study finds that 1 in 15 Americans (or 6.5 percent) over the age of 40 experiences ...

US drug overdose deaths surge amid fentanyl scourge

August 16, 2018
US drug overdose deaths surged to nearly 72,000 last year, as addicts increasingly turn to extremely powerful synthetic opioid fentanyl as the supply of prescription painkillers has tightened.

Parental life span predicts daughters living to 90 without chronic disease or disability

August 15, 2018
Researchers at the University of California San Diego School of Medicine report that women whose mothers lived to at least age 90 were more likely to also live to 90, free of serious diseases and disabilities.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.