Tuesday, December 16, 2008

Dodgy D'Anci

Just a few comments after reading through Stan's latest dodgy paper, the one by D'Anci et al in Appetite.

Here are some of my favorite quotes:

"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"

Okaaaay. A week of zero carbs, a week of under 8g/d and a week of under 16g/day. If anyone has a spare copy of Dr Atkins New Diet Revolution, perhaps they could send it to D'Anci. She might even read it before her next "similar to the AtkinsTM" study. Or maybe not. After all, quoting the AtkinsTM diet is hard for a main stream nutritionist who thinks high fibre, brightly coloured, mostly leaf based vegetables are actually healthy. Especially the number of servings Atkins suggested of this mainstream approved garbage. You don't get many of the AtkinsTM induction veggies on zero carbs per day!

"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"

This is exactly what they found, that the cognitive impairment of zero carbing can be reversed by as little as 8g/d of carbohydrate. Perhaps skipping the zero carb phase would have left the study with absolutely no anti LC data? After all, the ADA dieters had higher confusion scores than the LC group at all time points...

"...weight loss was not significantly different over the 3-week experimental period, weight loss was less than 2 kg in each group (LC diet M = 1.88 kg; ADA diet M = 1.76 kg; n.s.)"

This is impressive. I can't really see how they achieved this. On an intensely ketogenic, carbohydrate restricted diet there was only slightly more weight loss in the LC group than could be achieved by simply following the ADA advice for weight loss. You would have expected the water loss from metabolism of liver glycogen would have accounted for a significantly greater weight loss in the first week in the zero carb group compared to the ADA group. How can this be? Beats me. Maybe the LC group were told to eat enough protein to keep out of ketosis? How can you tell? Nothing in the methods.

And this one, the absolute crowning achievement:

"Hunger ratings did not vary between the two diet conditions"

Sooooo, the AtkinsTM diet is a NON CALORIE RESTRICTED diet which, if actually followed, produces progressive weight loss. The ADA (low calorie macronutrient balanced) dieter's advice re calories is stated in the methods section as:

"Individuals who selected the ADA diet calculated their recommended caloric intake per day based on their current weight"

The closest I could find to what this really means on the ADA website was:

"An individualized reduced calorie diet is the basis of the dietary component of a comprehensive weight management program. Reducing dietary fat and/or carbohydrates is a practical way to create a caloric deficit of 500 – 1000 kcals below estimated energy needs and should result in a weight loss of 1 – 2 lbs per week."

It doesn't actually say anywhere in the paper how much of anything the participants ate! But what ever they ate, they were either HUNGRY on the AtkinsTM like diet or not hungry at all on a caloric deficit of up to 1000kcal on the ADA diet. Smell of fish here?

Another gem from the homilies in the discussion:

"Participants most likely selected into a diet best fit their eating habits, although this was not assessed. If so, the diet conditions may not have been sufficiently different from normal to produce much dysphoria or food preoccupation"

Zero carb is close to the diet of exactly how many Americans?

And finally (got to stop some time!)

"Another common phrase may be an important reminder to these prospective dieters—You Are What you Eat"

Humans are fat and protein, with a little carbohydrate thrown in. Maybe that's what we should eat!

Peter

16 comments:

donny said...

If they wanted to know that the tiny increase in carbs (rather than just low carb adaption) was responsible for the improvement, they would have had to have had some of the zero carb participants stay zero carb as a control.

Peter said...

Absolutely. Could just have been adaption. Adding back 8g/d isn't exactly going to replete glyciogen stores is it?

Peter

Stan (Heretic) said...

Hi Peter,

I actually got the full text later on but gave up on trying to argue it since there was no meat in it!

(They also banned me from McDougall's forum after I posted about vit K2 and healthy teeth on high fat+meat diets, so I couldn't respond...)

There was nothing in that paper that would tell us what exactly they ate and how much. That is one of the most garbagey unscientific writup I have seen for a long time. I though nothing would surprise any more about those medical "researchers" but they seem to be surpassing themselves.

Regards,
Stan (Heretic)

mark said...

There is also a problem of the average ages of the two cohorts being unknown. Participants were 22-55 years old.

Given that the study had an anti-low carb bias, and that age information for the cohorts was not provided, I suspect the average age of the low-carb group was much higher than that of the ADA group. This might account for the reaction time differences and cognitive performance.

Mark.

Stan (Heretic) said...

Re: I suspect the average age of the low-carb group was much higher than that of the ADA group.

VEry likely! It would explain why they claimed that the pseudo-Atkins group was chosen based on their preferences. They may have been the people who tried Atkins before. That is almost always older people, in my experience (observations). Virtually everyone who adopts Optimal Diet in Poland is either old or sick or both. It is often the last resort therapy when everything else fails.

That vegan forum I mentioned, took that paper as a "proof" against the LC diets in general even though the study itself does not claim so, in fact they wrote that both groups suffered from mental impairments albeit of different kind: LC group during the zero carb stage; ADA group during the whole process.

Zbig said...

> Virtually everyone who adopts
> Optimal Diet in Poland is either
> old or sick or both.

isn't it all over the world?
two major target groups for diets are :
A. young girls who need to fit into a smaller dress in a month's time
B. older folks whose health deteriorates and they want to do something about it

Young and middle-aged males with "beer bellies" just don't need any diet, they will cut on beer but not today yet :)

Group A fears of fat so they pick what's available in Polish and have a good reputation and support on the internet - mostly Montignac and South Beach

Group B don't read these fads, they talk in the doctor's waiting rooms and they quite often have heard of a cousin or a neighbor who got rid of some problems with this fat diet...

Basically that's how it works, and yet another group of "optimals" are "internet fighters" who engage in countless fights and debates with vegetarians :)

Stan (Heretic) said...

Basically that's how it works, and yet another group of "optimals" are "internet fighters" who engage in countless fights and debates with vegetarians :)

Zbig, this is so true I cannot even comment! 8-:)

I have to say that after they banned me on one vegan forum and my account conked out on webmd due to some software glitch, I decided to cut down on that addiction. I am getting better, except Peter may see me more often here (sorry)... 8-:)

Stan (Heretic) said...

Another dodgy paper:

Progressive bone mineral content loss in children with intractable epilepsy treated with the ketogenic diet

http://www.ajcn.org/cgi/content/abstract/88/6/1678

I am curious what exactly did they feed to the children, I am suspecting vegetable oil. Since they also showed a decline in vitamin D, I doubt if they were getting animal fat and probably not enough meat either.

Lauren said...

Thanks for breaking it down, Pter. That study was rather frustrating to sift through! The fact that it got so much press was equally depressing. I'd have brain fog at ZERO grams of carbs, too!

Peter said...

You're very welcome Stan!

Peter said...

Stan, AJCN is always hard to get the full text on recent papers and, even if you could get it, it might not necessarily give you the actual foods used, though clearly if it talks about cholesterol concerns you can assume PUFA, probably omega 6. I doubt anyone would really want to be on a fully ketogenic diet unless they had a serious epilepsy problem. The question then is whether something as mild as the OD would work. I certainly know of anecdote (through yourself?) that it can work for "ordinary" epilepsy. But perhaps not for these serious resistant cases...

Peter

Stan (Heretic) said...

Re: I doubt anyone would really want to be on a fully ketogenic diet unless they had a serious epilepsy problem. The question then is whether something as mild as the OD would work.

Hi Peter,

Yes it does. There is a recent paper that tested Atkins' diet on epileptic children and they concluded that it works just as well. I will dig it out later.
Regards,
Stan

Peter said...

Hmmmm, fits well with the low dose coconut oil in Alzheimers. Us moderate ODers are on the right track...

Stan (Heretic) said...

"Controversial Atkins Diet may be beneficial for people with epilepsy"

http://www.eurekalert.org/pub_releases/2005-01/bpl-cad013105.php

ItsTheWooo said...

I know even small bits of carb make a tremendous difference in how I feel, so I wouldn't dismiss the possibility that a slight bit of extra carb helped. A NO carb diet is absolutely unnatural. Even if we are talking about innuit eating nothing but animals, it's assumed they're eating carb-containing liver and innards, right?
I would not expect humans to ideally thrive on zero carbs.


Good catch re: age and diet preference. As a 20 something I can tell you that low carb is supremely uncool. Older people are attracted to low carb, they're less brainwashed by vegan propaganda and what not.

On a low carb forum, people younger than 35 will be rare.
On a vegetarian/vegan forum, people older than 35 will be rare.




Regarding kids on the ketogenic diet... it also needs to be considered the THERAPUTIC ketogenic diet is not at all like a regular low carb diet. This is a very protein restricted way of eating. Osteoporosis is mainly about protein or deficient growth hormones ... that is, NOT ENOUGH of it. The kids grow slowly and have poor bones because they are fed nothing but lipids. Even water is restricted, because fluids can dilute the ketone level potentially triggering a seizure.

I suppose that level of strictness is necessary for some epileptics but there's evidence something as liberal as atkins induction is reasonably effective for epilepsy. Shame, all of that limited food choice, growth retardation and fluid restriction for nothing.

It's highly effective for my mood problems, which I suppose can be considered a form of epilepsy (screwed up cell metabolism leading to irrational energy/mood).

Bris said...

I simply can't see any valid reason why anyone needs any carbohydrates:

- the brain functions as well or better on ketones than glucose.

- glucose is readily synthesised from protein by gluconeogenesis.

- the muscles contain about 100g of glycogen and the liver another 400g. This is 2000 KCal of energy.

When I was 20 I undertook a military survival exercise. I had zero food for three days. Apart from hunger there were absolutely no side effects at all from starvation.