The greater your weight, the lower your IQ, say scientists

[Demi]

The Sunday Telegraph
London, UK
Published: 15 October, 2006



It is bad for your blood pressure, knocks years off your life and is a strain on your heart. Now scientists have discovered that gaining weight lowers your intelligence.

The findings follow last week's government figures that show Britain as the "fat man" of Europe, with nearly a quarter of adults and more than 14 per cent of children under 16 classified as obese.

The new five-year study of more than 2,200 adults claims to have found a link between obesity and the decline in a person's cognitive function. The research, conducted by French scientists, which is published in this month's Neurology journal, involved men and women aged between 32 and 62 taking four mental ability tests that were then repeated five years later.

The researchers found that people with a Body Mass Index – a measure of body fat – of 20 or less could recall 56 per cent of words in a vocabulary test, while those who were obese, with a BMI of 30 or higher, could remember only 44 per cent.

The fatter subjects also showed a higher rate of cognitive decline when they were retested five years later: their recall dropped to 37.5 per cent, whereas those with a healthy weight retained their level of recall.

According to British guidelines, a person with a BMI of between 18.5 and 25 is considered to be at an ideal weight, while 25 is overweight and 30 or more is regarded as clinically obese.

Dr Maxime Cournot, who headed the study, suggested that hormones secreted from fats could have a damaging effect on cerebral cells, resulting in decreased brain function. "Another explanation could be that since obesity is a widely known cardiovascular risk factor, due to the thickening and hardening of the blood vessels, that the same happens with the arteries in the brain," said Dr Cournot, an assistant professor in clinical epidemiology at Toulouse University Hospital.

Dr David Haslam, the clinical director of the National Obesity Forum, said the research was alarming. "It goes to show obesity affects every single organ in the human body," said Dr Haslam.

But Ann Widdecombe, the former Tory minister, said that the research seemed unsustainable. "You just need to look around the world and you will see hundreds of thin nitwits and clever fat people," said Ms Widdecombe, who lost two stone when taking part in the television show Celebrity Fit Club.

"When I lost weight it was my waistline that improved, not my cerebellum."


http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/10/15/nweight15.xml

[KvonM]

ok i'm offended. there's no indication that this study took anything OTHER than weight and vocabulary into account... it says nothing about the person's overall IQ, nothing about their upbringing, what schools they attended, what jobs they held, nothing other than fat = stupid.

[Nancy LC]

I believe it isn't the weight that is the factor, it's the high carb diet that goes onto progress into diabetes, senility and so on. Poor blood glucose levels wreck the brain. The weight is only one of the symptoms of the crappy diet everyone is eating.

Bad journalism strikes again.

[kyrasdad]

If you do drop IQ as you gain weight, it's possible that the weight itself isn't the problem - the poor nutrition is. I believe your mental functions are inexorably tied to physical ones, for what that's worth. That doesn't mean a trim, athlete is always smarter than a fat guy, it's just that the fat guy might not be as intelligent as he could be if he ate right.

[Whoa182]

I noticed a massive difference in memory when I stopped eating junk food and ate more healthy... so yeah, you are probably right. Saying that, there IS still a decline with age in memory function, even if you have the best diet. But there is probably no reason to think that by improving nutrition and testing these subjects again, there would be no improvement.

[ItsTheWooo]

Obesity is a symptom. To be obese precludes an elevation in insulin secondary to a decrease in the capacity for metabolism to create and use energy from food (peripheral insulin resistance). As tired and sluggish as carb eating obese people are (due to energy starvation) so is their brain foggy and slow. These effects are from the metabolic abnormalities secondary to insulin resistance as well as the resulting energy starvation.

[ItsTheWooo]

My cognative abilities - especially memory - has improved so much since low carbing and taking fish oil. As soon as I started LC, my depression got 110% better almost overnight. A high energy LC diet is essential.
The fish oil is an independent factor, as the most pronounced increases in emotional and intellectual improvements were observed these past few months of supplementing 1 g / day of epa and dha. Fish oil has improved my memory, and it has also helped even my moods and elevate the height and frequency of my ability to feel happy.

Whoa: It is well known low energy diet and underweight decrease memory, learning (of new information), and emotional feeling as well.
Learning and emotions are very similar processes (an evolutionary adaption). If the body perceives stress / trauma, it manipulates neurotransmitter activity (level/action) to extinguish emotions, learning, and memory. If the capacity to feel, learn, and remember were well preserved during acute trauma, imagine the long term implications. Needless to say, if the body detects starvation, the body detects stress.
If your cognative abilities and emotional state has improved underweight and energy restricted, this is merely evidence that your pervious diet disagreed with your body an extreme amount. It is likely you would enjoy even better functioning if you increased energy and maintained a healthy weight.

[kyrasdad]

I noticed a massive difference in memory when I stopped eating junk food and ate more healthy... so yeah, you are probably right.

Same with me. I am sharper than ever. It is something I didn't expect.

I suspect that even if I hadn't dropped a pound, I would have been sharper just because I wasn't subsisting on thousands of calories of refined junkfood, but mostly whole foods. My caloric intake declined, but not by as much as you'd think.

Like Wooo said, obesity and decreased intellect (the "fog" she refers to is a perfect description of it) are symptoms of the same problem - poor nutritional content.

[Whoa182]

Whoa: It is well known low energy diet and underweight decrease memory, learning (of new information), and emotional feeling as well.

Possibly when you go too low in calories yes (as some people reported in the CR lists and even DR walford himself), but I don't consider 1700-1800 for a mainly sedentary person to be extremely low. Also I am a small body frame. I am CERTAIN my concentration and ability to learn has increased since I hate healthy and started taking fish oil.

Learning and emotions are very similar processes (an evolutionary adaption). If the body perceives stress / trauma, it manipulates neurotransmitter activity (level/action) to extinguish emotions, learning, and memory.

If the capacity to feel, learn, and remember were well preserved during acute trauma, imagine the long term implications. Needless to say, if the body detects starvation, the body detects stress.

Check this out about hunger and memory

Hunger pangs 'may trigger memory'
http://news.bbc.co.uk/1/hi/health/4723162.stm

"New research suggests it may be wise to revise for and sit exams on an empty stomach as hunger can help with the creation and retrieval of memories. American scientists found the hunger hormone ghrelin can increase the number of nerve connections in the area of the brain where new memories are formed. "

If your cognative abilities and emotional state has improved underweight and energy restricted, this is merely evidence that your pervious diet disagreed with your body an extreme amount.

Well I mainly lived on cereal for a lot of my teen years, I always ate around 3 big bowls of wholegrain cereal a day and lots and lots of whole fat milk.

It is likely you would enjoy even better functioning if you increased energy and maintained a healthy weight

Yeah possibly... and I'm sure I will gain weight in time, I really doubt I'll need to do this CR more than 10-20 years anyway.

As I said in the other thread though, I eating several meals and snacks a day. What also helps I find is protein, when I eat a high carb meal without protein I don't feel as good or as alert. I always get at least 30% protein with my meals now...

[ItsTheWooo]

Skipping a meal. Meal to meal hunger won't produce the kind of stress state I'm talking about, as meal to meal hunger is a normal occurrence that is not perceived as abnormal stress. Abnormal stress (related to food/diet/weight) comes from a chronic low energy diet, with a too low body fat (indicators of starvation). Evolutionarily speaking, it is highly adaptive for acute hunger to be associated with memory formation. I am not surprised to see that Ghrelin (pre-meal hunger hormone) helps form new memories.

It is far less advantageous to remember all the little details about being immobilized from low energy, poor effect, and extreme hunger (famine, starvation state). In the natural world, indication of starvation only occurs IN starvation - fad dieting, eating disorders, CRON, and other neurotic habits of modern humans don't apply :) .
At the point of chronic/severe stress, it becomes an issue of trying to stay alive long enough for it to pass... there is little choice to respond and stop it. If it were possible to stop it, the person WOULD have done so before the stress became chronic/severe in the first place. Chronic stress is like a little flag telling the body "something really bad is going on and our existence is threatened; try to stay alive". It tells our genes there is a major environmental shift occurring, and we aren't jiving.
If/ when it does pass, there is no advantage to retaining the experiences in vivid detail. It is most likely beyond your scope of control to stop or prevent it, because if it were possible, we would have done so before it became chronic. Therefore, retaining the trauma would yield no benefit, and it would only impair functionality in the recovered stage (emotional maladjustment).

Therefore, the greater and more chronic stress a person is under, the more impaired their emotions/learning capacity. In fact, it is hypothesized eating disorders are an attempt to obliterate unpleasant feelings, and chaotic/traumatic circumstances, by triggering a highly stressful state (thus producing numbness and reduced memory access/formation).

[LilithD]

I'm dubious about this. Firstly, BMI, as we saw in a recent post, is a very poor tool. Secondly, as people have said above, it could be far more to do with insulin resistance than actual obesity. Thirdly, I've know many chubby people who were pretty damn smart!

[Whoa182]

I don't know what to say :) other than...

Since going on CR and eating healthy I started to read books (never read a full book before I started CR) about everything, and I must have read hundreds of books and many published stuff on the net. I just had this massive thirst for knowledge, which I think came from supplementing with omega 3 for about 2-3 months, but could also be the change of diet too. And I also retain what I learn very well. I think i've learned more in the last two years than I did the whole time I was in high school!

[Dodger]

I don't know what to say :) other than...

Since going on CR and eating healthy I started to read books (never read a full book before I started CR) about everything, and I must have read hundreds of books and many published stuff on the net. I just had this massive thirst for knowledge, which I think came from supplementing with omega 3 for about 2-3 months, but could also be the change of diet too. And I also retain what I learn very well. I think i've learned more in the last two years than I did the whole time I was in high school!Whoa, it could be that you have reached that stage called 'maturity'.

[KarenJ]

Same with me. I am sharper than ever. It is something I didn't expect.

I suspect that even if I hadn't dropped a pound, I would have been sharper just because I wasn't subsisting on thousands of calories of refined junkfood, but mostly whole foods. My caloric intake declined, but not by as much as you'd think.

Like Wooo said, obesity and decreased intellect (the "fog" she refers to is a perfect description of it) are symptoms of the same problem - poor nutritional content.


Same here. The mental clarity I have now makes the fog I suffered previously even more profound.

I don't call it Brain Fog, I call it Grain Fog. :lol:

[Nancy LC]

Grain Fog! I love it. I also get Milk Brain. :p

[Samuel]

Learning and emotions are very similar processes (an evolutionary adaption). If the body perceives stress / trauma, it manipulates neurotransmitter activity (level/action) to extinguish emotions, learning, and memory. If the capacity to feel, learn, and remember were well preserved during acute trauma, imagine the long term implications. Needless to say, if the body detects starvation, the body detects stress.
Woo, I have a simpler explanation for what you are saying.

When I'm overweight and somebody explains something to me, I get plenty of "garbage" thoughts in my mind which reduces my concentration. Such thoughts are like "Why is he looking at me this way?. Is it because I look bad?!". This is in addition to the pains I feel due to tight belt and clothes which also keep my brain too busy to concentrate on whatever is said to me!