Low Carb Diet Is Bad For Thinking And Memory (Medical News Today)

wrote:

http://www.ng2000.com/blog/2008/11/10/low-carb-diet/

The actual study is

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
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WB2-4TB181Y-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view =c&_acct=C000050221&_version=1&_urlVersion=0&_user id=10&md5=8ac6c083c0959d22333692a2c85fdb49
http://tinyurl.com/62c46h

Abstract:

"To examine how a low-carbohydrate diet affects cognitive
performance, women participated in one of two weight-loss diet
regimens. Participants self-selected a low-carbohydrate (n = 9)
or a reduced-calorie balanced diet similar to that recommended
by the American Dietetic Association (ADA diet) (n = 10).
Seventy-two hours before beginning their diets and then 48 h,
1, 2, and 3 weeks after starting, participants completed a
battery of cognitive tasks assessing visuospatial memory,
vigilance attention, memory span, a food-related paired-
associates a food Stroop, and the Profile of Moods Scale (POMS)
to assess subjective mood. Results showed that during complete
withdrawal of dietary carbohydrate, low-carbohydrate dieters
performed worse on memory-based tasks than ADA dieters. These
impairments were ameliorated after reintroduction of
carbohydrates. Low-carbohydrate dieters reported less
confusion (POMS) and responded faster during an attention
vigilance task (CPT) than ADA dieters. Hunger ratings did not
differ between the two diet conditions. The present data show
memory impairments during low-carbohydrate diets at a point
when available glycogen stores would be at their lowest. A
commonly held explanation based on preoccupation with food
would not account for these findings. The results also suggest
better vigilance attention and reduced self-reported confusion
while on the low-carbohydrate diet, although not tied to a
specific time point during the diet. Taken together the
results suggest that weight-loss diet regimens differentially
impact cognitive behavior."

The page

http://www.sciencedirect.com/science/journal/01956663

has a link to PDF file of the full text of the study. It is
the article number 16 on this table of contents page. Yesterday
I was able to download the full text PDF free from this page,
but not from the abstract page. Now, when I try again, there
seems to be some problem with starting the download, perhaps
they are maintaining their server or something-

I quote Ron Peterson's recent message about this study in
sci.med.nutrition:

"The study says:

The present study examined how the initial stages of two
weight-reducing diets, a low-carbohydrate diet similar to the
AtkinsTM diet, and another with macronutrients proportions
typically recommended by the American Dietetic Association
(ADA), affect cognitive performance. Low-carbohydrate diets
typically have a 2-week introductory period wherein people
severely limit carbohydrates. After this point, carbohydrates are
gradually reintroduced, but generally remain below the RDA. To
mimic this pattern of restriction and reintroduction of dietary
carbohydrate, participants followed a 3-week dietary regimen that
included a 1-week period that eliminated carbohydrates. We
proposed that dietary carbohydrate restriction would impair
cognitive performance in the early phases of the diet, and that
this impairment would be ameliorated by the reintroduction of
carbohydrate.

and

Upon enrollment, participants chose either the LC or the ADA
diet—a macronutrient nutritionally balanced diet, akin to the 2005
American Dietetic Association guidelines diet. After selecting a
diet, the investigator thoroughly reviewed the diet guidelines and
discussed the nature of the study with the participant. Individuals
who selected the LC diet received instructions to reduce their daily
carbohydrate intake to 0 g for 1 week. For the second week, they
could add between 5 and 8 g of carbohydrates per day. For the third
week, they could add an additional 5–8 g per day (total 10–16 g per
day). Individuals who selected the ADA diet calculated their
recommended caloric intake per day based on their current weight.
Then, a list based on the ADA Food Exchange List (NHLBI Web site,
most recently accessed on 14/8/2007) was reviewed and given to
participants. All participants, regardless of diet, received a food
journal and instructions to maintain a strict record of every food
and beverage consumed over the course of the study. In addition,
they were asked to avoid any food or beverage labeled as having
‘‘net carb’’ values, as these products were not standardized by the
FDA for carbohydrate value at the time of the study. Participants
continued on their selected diet for 3 weeks."

In the abstract the sentence "Results showed that during complete
withdrawal of dietary carbohydrate, low-carbohydrate dieters performed
worse on memory-based tasks than ADA dieters", implies that during
temporary memory impairment low-carbers were getting _zero_ carbs.
That does not sound very realistic in real life, at least not in
long term. But it was not all bad for low-carbers according to the
sentence "The results also suggest better vigilance attention and
reduced self-reported confusion while on the low-carbohydrate diet,
although not tied to a specific time point during the diet".

--
Matti Narkia

http://ma.gnolia.com/groups/Nutrition

On Dec 13, 1:15*pm, Matti Narkia wrote:
wrote:
http://www.ng2000.com/blog/2008/11/10/low-carb-diet/

The actual study is

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
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WB2-4TB181...
http://tinyurl.com/62c46h

Abstract:

* * * "To examine how a low-carbohydrate diet affects cognitive
* * * performance, women participated in one of two weight-loss diet
* * * regimens. Participants self-selected a low-carbohydrate (n = 9)
* * * or a reduced-calorie balanced diet similar to that recommended
* * * by the American Dietetic Association (ADA diet) (n = 10).
* * * Seventy-two hours before beginning their diets and then 48 h,
* * * 1, 2, and 3 weeks after starting, participants completed a
* * * battery of cognitive tasks assessing visuospatial memory,
* * * vigilance attention, memory span, a food-related paired-
* * * associates a food Stroop, and the Profile of Moods Scale (POMS)
* * * to assess subjective mood. Results showed that during complete
* * * withdrawal of dietary carbohydrate, low-carbohydrate dieters
* * * performed worse on memory-based tasks than ADA dieters. These
* * * impairments were ameliorated after reintroduction of
* * * carbohydrates. Low-carbohydrate dieters reported less
* * * confusion (POMS) and responded faster during an attention
* * * vigilance task (CPT) than ADA dieters. Hunger ratings did not
* * * differ between the two diet conditions. The present data show
* * * memory impairments during low-carbohydrate diets at a point
* * * when available glycogen stores would be at their lowest. A
* * * commonly held explanation based on preoccupation with food
* * * would not account for these findings. The results also suggest
* * * better vigilance attention and reduced self-reported confusion
* * * while on the low-carbohydrate diet, although not tied to a
* * * specific time point during the diet. Taken together the
* * * results suggest that weight-loss diet regimens differentially
* * * impact cognitive behavior."

The page

http://www.sciencedirect.com/science/journal/01956663

has a link to PDF file of the full text of the study. It is
the article number 16 on this table of contents page. Yesterday
I was able to download the full text PDF free from this page,
but not from the abstract page. Now, when I try again, there
seems to be some problem with starting the download, perhaps
they are maintaining their server or something-

I quote Ron Peterson's recent message about this study in
sci.med.nutrition:

"The study says:

The present study examined how the initial stages of two
weight-reducing diets, a low-carbohydrate diet similar to the
AtkinsTM diet, and another with macronutrients proportions
typically recommended by the American Dietetic Association
(ADA), affect cognitive performance. Low-carbohydrate diets
typically have a 2-week introductory period wherein people
severely limit carbohydrates. After this point, carbohydrates are
gradually reintroduced, but generally remain below the RDA. To
mimic this pattern of restriction and reintroduction of dietary
carbohydrate, participants followed a 3-week dietary regimen that
included a 1-week period that eliminated carbohydrates. We
proposed that dietary carbohydrate restriction would impair
cognitive performance in the early phases of the diet, and that
this impairment would be ameliorated by the reintroduction of
carbohydrate.

and

Upon enrollment, participants chose either the LC or the ADA
diet—a macronutrient nutritionally balanced diet, akin to the 2005
American Dietetic Association guidelines diet. After selecting a
diet, the investigator thoroughly reviewed the diet guidelines and
discussed the nature of the study with the participant. Individuals
who selected the LC diet received instructions to reduce their daily
carbohydrate intake to 0 g for 1 week. For the second week, they
could add between 5 and 8 g of carbohydrates per day. For the third
week, they could add an additional 5–8 g per day (total 10–16 g per
day). Individuals who selected the ADA diet calculated their
recommended caloric intake per day based on their current weight.
Then, a list based on the ADA Food Exchange List (NHLBI Web site,
most recently accessed on 14/8/2007) was reviewed and given to
participants. All participants, regardless of diet, received a food
journal and instructions to maintain a strict record of every food
and beverage consumed over the course of the study. In addition,
they were asked to avoid any food or beverage labeled as having
‘‘net carb’’ values, as these products were not standardized by the
FDA for carbohydrate value at the time of the study. Participants
continued on their selected diet for 3 weeks."

In the abstract the sentence "Results showed that during complete
withdrawal of dietary carbohydrate, low-carbohydrate dieters performed
worse on memory-based tasks than ADA dieters", implies that during
temporary memory impairment low-carbers were getting _zero_ carbs.
That does not sound very realistic in real life, at least not in
long term. But it was not all bad for low-carbers according to the
sentence "The results also suggest better vigilance attention and
reduced self-reported confusion while on the low-carbohydrate diet,
although not tied to a specific time point during the diet".

--
Matti Narkia

http://ma.gnolia.com/groups/Nutrition


LOL. It gets even more bizarre. I'd like to see the food log of
what these people ate. They supposedly ate 0g of carbs the first
week, and then 5 to 8 the second? I would submit that without
closely watching these people, it's quite difficult to do this in the
real world, chosing and eating your own real foods.

But maybe best of all, is as you point out, what exactly is their
point? Apparently they say mental performance improved as carbs were
added back, but they only went from 0 carbs to 10 to 16 grams by the
third and final week. And that shows that a "low" carb diet impares
mental performance? I'd say even if they really were consuming 0
carbs for a week, and ther results were valid, it shows that the first
week of a zero carb diet impared mental performance and that in a
couple of weeks when you are anywhere near even Atkins induction level
of carbs, the effect is gone.

It 's just another example of how LC equates with some morons to an
extreme diet of 0 carbs, when in fact it is something quite different.