Tuesday, January 31, 2012

The diabetes boogeyman: Does diabetes make you fat rather than the other way around?

A boogeyman often invoked by the food fascists in their efforts to get control over what we eat

That obesity causes diabetes is one of the most entrenched medical mantras that there is. Even the (mythical) lifespan benefits of statins and antioxidants are not as often invoked as the relationship between obesity and diabetes. I think I see the relationship touted at least once a day somewhere.

But think!

* Most overweight people don't get diabetes and some diabetics are slim!

* It is true that certain diets can help control diabetes but that does not mean that diet causes diabetes. A roof can shelter me from the rain but that does not mean that roofs cause rain!

* There is undoubtedly a correlation between being overweight and having obesity but correlation is not causation and it could well be that at least in some people diabetes causes you to put on weight. I have certainly seen instances of the latter, where an overweight person discovered they had diabetes, went on a diabetic diet and promptly lost a lot of weight. It was apparently diabetes that was making them fat. Excessive appetite is a known symptom of diabetes so that is hardly a surprise. And all the so-often-quoted research findings are just correlations, so prove nothing about which way the causal arrow points.

* There are various studies of diabetes in mice but mice are a very short-lived species whereas we are a very long-lived species. We have obviously evolved life-preserving mechanisms that mice have not so what is a problem in mice might be quite easily coped with by the human body. And that is one reason why rodent findings often do not generalize to people.

So I am going to reproduce below something I wrote in 2008. I know of nothing which would alter my conclusions since. If anybody can tell me something important that I have overlooked, however, I would be delighted to hear it:
I decided to look at the evidence behind the claim. I looked at what appear to be the two most cited articles on the question — by Seidell and by Mokdad et al..

Neither article goes any where near proving the claim. Seidell, in fact, notes the differing relationship between weight and diabetes in Asia versus the West and makes the entirely sensible observation that the two things are “common consequences of changing lifestyles” — NOT directly linked, in other words. Both, for instance, could be a consequence of (say) reduced exercise.

And the Mokdad article is quite naive. It shows that fatties are more likely to have diabetes but again enables no causal inferences. Additionally, it does not allow for the curvilearity that is known to feature in relationships with obesity. In other words, it combines moderately overweight people with grossly overweight people — which flies in the face of the fact that it is people of middling weight who live longest. It could be just the real fatties who tend to get diabetes at an accelerated rate.

And genetic effects are, of course, not mentioned anywhere, despite all we know (and have known for a long time) about the genetic influence on body weight. It could be that a genetic difference causes both diabetes AND a larger fat mass. So even severe dieting would not chase that pesky diabetes-causing gene away.

The fact that prevalence of diabetes has been increasing would seem at first to discount a genetic influence but it does not, of course. Many genetic influences need environmental “triggers” to become dominant and we just don’t know what environmental triggers might have come to the fore in recent years. How about increased crime causing both stress and overeating as a response to stress? Who knows?

As far as I can see, then, the alleged effect of fat on diabetes is just a guess. Ho hum! Just another instance of crap medical “wisdom”.

I wonder do pigs get diabetes? Fat pigs are a byword. And pigs are a pretty good animal model for human beings. Pig tissue is even used for direct implantation into human hearts! Rodent models always have dubious generalizability but I think I would believe a double-blind study with pigs.

So, you see, I am not like those (such as the Global Warmists) for whom no evidence will count. I have just specified precisely what evidence would convince me. And nor would the evidence concerned be hard to gather. You might even get some good bacon at the end of it! Yum!


An example here of diabetes being associated with weight-gain and the gain being reversed by dealing with the diabetes. That train of events DOES suggest a causal inference: That it was the diabetes that caused the weight gain and not vice versa.

Update 2: Aborigines

I probably should say something about diabetes among Australian Aborigines. Within living memory, diabetes was virtually unknown among Aborigines but it is now very common. This is of course very interesting epidemiology and dietary change is the conventional explanation. At the beginning of the period Aborigines still fed themselves mostly by traditional hunter/gatherer activities and so got plenty of exercise and a varied diet of minimally processed food.

Nowadays with more generous government welfare provision they subsist largely on the most disparaged of Western foods --such as Coke and potato chips. That this switch from an aspirational diet to a disparaged one has been accompanied by a rise in diabetes tends to give epidemiologists erections. It should not, however, as there have been other large changes at the same time -- in particular the availability of alcohol has greatly increased.

At the beginning of the period it was in fact illegal to supply Aborigines with alcohol. Unlike Westerners, they have not had millennia to adapt to it and so handle it very badly. But paternalistic restrictions are out of fashion now so there is now a very large alcohol abuse problem in Aboriginal communities and it seems entirely possible that this is behind the diabetes upsurge.

To make matters worse, there is today a definite problem with "metho", which was at least much less in the past. "Metho" is a combination of ethyl alcohol and methyl alcohol, a quite poisonous product, but it is cheap and very intoxicating -- and some stores frequented by Aborigines are even reputed to keep it in the fridge for sale to Aborigines as a beverage. It even has a pet name among Aborigines: "White lady". How they survive drinking it at all is a mystery.

So diet is only one candidate for explaining health problems among Aborigines.

I should perhaps end up with a clarifying note: In all my remarks above I had in mind the form of diabetes that accounts for at least 90% of the cases: Diabetes mellitus type 2.

Fun breakfast freaks the do-gooders

A monster breakfast which weighs the same as a small child and could potentially kill diners is attracting criticism from angry health campaigners

The Kidz Breakfast at Jesters Diner in Great Yarmouth, Norfolk, includes 12 rashers of bacon, 12 sausages and six eggs and weighs on average 9lb - 1lb 5oz more than the average newborn baby.

Health experts are demanding its removal from the menu and are warning someone with a heart condition could die if they eat it, with each helping amounting to at least 6,000 calories, up to three days' food intake for an average person.


12 rashers of bacon
12 sausages
Six eggs
Four black pudding slices
Four slices of bread and butter
Four slices of toast
Four slices of fried bread
Two hash browns
Eight-egg cheese and potato omelette
Saute potatoes

Greasy spoon owner Martin Smith said the gigantic breakfast, which comes on a 2.5 sq ft plate, is 'just a bit of fun', with the menu inviting diners to tuck in and 'leave a stone heavier'.

Customers are also offered the £15 mammouth meal for free if they can devour the fry-up in less than an hour without help but no one has managed the stomach bursting feat.

Ellie Hambling, from HeartCare Cardiac Support Group, said: 'It would absolutely ruin your heart. It’s a no-goer I’m afraid.'

Prof David Haslam, from the National Obesity Forum, warned it 'is possible' someone could die after eating the meal in a single sitting, but added it was 'very unlikely'. He said eating the breakfast was 'dangerous' and 'profoundly wrong' and could lead to diabetes, heart disease and a stroke. Prof Haslam added the diner should take responsibility by 'taking it off the market'.

The breakfast has not yet been assessed by Guinness World Records, but according to records would take the title of the largest commercially available English breakfast.

The current holder, as of 1 December 2009, could be bought at Mario’s Cafe Bar in Westhoughton, Bolton, weighing an average of 6lb 7oz.

Mr Smith said: “We kept getting hassled that our Fat Boy Breakfast wasn’t big enough so we decided that we’d go one stage further and take it to the ultimate.”

He added: “Obviously this is not something that should be attempted lightly. We don’t particularly recommend it. It’s just a bit of fun really.”

The diner owner has refused to take his big breakfast off the menu but has agreed to help raise money for the HeartCare charity.


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