Featured Research

from universities, journals, and other organizations

Low-carb Diets Can Affect Dieters' Cognition Skills

Date:
December 15, 2008
Source:
Tufts University
Summary:
A new study shows that when dieters eliminate carbohydrates from their meals, they performed more poorly on memory-based tasks than when they reduce calories, but maintain carbohydrates. When carbohydrates were reintroduced, cognition skills returned to normal.

A new study from the psychology department at Tufts University shows that when dieters eliminate carbohydrates from their meals, they performed more poorly on memory-based tasks than when they reduce calories, but maintain carbohydrates. When carbohydrates were reintroduced, cognition skills returned to normal.

Related Articles


"This study demonstrates that the food you eat can have an immediate impact on cognitive behavior," explains Holly A. Taylor, professor of psychology at Tufts and corresponding author of the study. "The popular low-carb, no-carb diets have the strongest potential for negative impact on thinking and cognition."

Taylor collaborated with Professor Robin Kanarek, former undergraduate Kara Watts and research associate Kristen D'Anci.

While the brain uses glucose as its primary fuel, it has no way of storing it. Rather, the body breaks down carbohydrates into glucose, which is carried to the brain through the blood stream and used immediately by nerve cells for energy. Reduced carbohydrate intake should thus reduce the brain’s source of energy. Therefore, researchers hypothesized that diets low in carbohydrates would affect cognitive skills.

Study participants included 19 women ages 22 to 55 who were allowed to select the diet plan they preferred -- either a low-carbohydrate diet or a low-calorie, macronutrient balanced diet recommended by the American Dietetic Association. Nine women chose a low-carbohydrate diet and 10 selected the low-calorie diet.

"Although the study had a modest sample size, the results showed a clear difference in cognitive performance as a function of diet," says Taylor.

The 19 dieters completed five testing sessions that assessed cognitive skills, including attention, long-term and short-term memory, and visual attention, and spatial memory. The first session was held before participants began their diets, the next two sessions occurred during the first week of the diet, which corresponded to the week when low-carb dieters eliminated carbohydrates. The final two sessions occurred in week two and week three of the diets, after carbohydrates had been reintroduced for those on the low-carb diet.

"The data suggest that after a week of severe carbohydrate restriction, memory performance, particularly on difficult tasks, is impaired," Taylor explains.

Low-carb dieters showed a gradual decrease on the memory-related tasks compared with the low-calorie dieters. Reaction time for those on the low-carb diet was slower and their visuospatial memory was not as good as those on the low-calorie diet. However, low-carb dieters actually responded better than low-calorie dieters during the attention vigilance task. Researchers note that past studies have shown that diets high in protein or fat can improve a person's attention in the short-term, which is consistent with the results in this study.

Participants were also asked about their hunger levels and mood during each session. The hunger-rating did not vary between participants on a low-carb diet and those on a low-calorie diet. The only mood difference between dieters was confusion, which was higher for low-calorie dieters during the middle of the study.

"Although this study only tracked dieting participants for three weeks, the data suggest that diets can affect more than just weight," says Taylor. "The brain needs glucose for energy and diets low in carbohydrates can be detrimental to learning, memory, and thinking."


Story Source:

The above story is based on materials provided by Tufts University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Danci et al. Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite, 2009; 52 (1): 96 DOI: 10.1016/j.appet.2008.08.009

Cite This Page:

Tufts University. "Low-carb Diets Can Affect Dieters' Cognition Skills." ScienceDaily. ScienceDaily, 15 December 2008. <www.sciencedaily.com/releases/2008/12/081211112014.htm>.
Tufts University. (2008, December 15). Low-carb Diets Can Affect Dieters' Cognition Skills. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2008/12/081211112014.htm
Tufts University. "Low-carb Diets Can Affect Dieters' Cognition Skills." ScienceDaily. www.sciencedaily.com/releases/2008/12/081211112014.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Says It Will Scale Up Its Ebola Response

UN Says It Will Scale Up Its Ebola Response

AFP (Nov. 20, 2014) UN Resident Coordinator David McLachlan-Karr and WHO representative in the country Daniel Kertesz updated the media on the UN Ebola response on Wednesday. Duration: 00:51 Video provided by AFP
Powered by NewsLook.com
Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Reuters - US Online Video (Nov. 20, 2014) U.S. Congress hears from a victim and company officials as it holds a hearing on the safety of Takata airbags after reports of injuries. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Obesity Costs Almost As Much As War And Terrorism

Obesity Costs Almost As Much As War And Terrorism

Newsy (Nov. 20, 2014) The newest estimate of the cost of obesity is pretty jarring — $2 trillion. But how did researchers get to that number? Video provided by Newsy
Powered by NewsLook.com
Ebola Crisis Affecting US Adoptions

Ebola Crisis Affecting US Adoptions

AP (Nov. 20, 2014) The Sanborn family had hoped they'd be able to bring home their 5-year-old adopted son from Liberia by now. But Ebola has forced them to wait. The boy is just one of thousands of orphans in West Africa who've been impacted by the deadly virus. (Nov. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins