Another study attests to the ineffectiveness of conventional ‘healthy’ eating advice

If I were to summarise what is conventionally regarded as a ‘healthy’ diet, I’d say it would be one which is low in fat, and rich in carbohydrate, including fruit and vegetables and fibre. I don’t particularly have much enthusiasm for such as diet myself: while I’m a general fan of fruit of veg, I don’t subscribe to the low-fat/high-carb paradigm that is at the core of conventional dietary recommendations. Why? Well, it’s got something to do with the fact that there really isn’t very much evidence that such an approach brings broad benefits for health. That’s why.

I was interested to read a study published in the latest edition of the European Journal of Clinical Nutrition which assessed the effect of a traditionally ‘healthy’ diet in a group of 750 adults aged 35 or over. Some of the group were assigned to the ‘healthy’ diet (which included instructions to consume no more that 20 per cent of their calories in the form of fat), and some weren’t. The study lasted for 4 years.

A number of measurements were made including blood sugar levels, insulin levels, and the levels of substances known as insulin-like growth-factors (IGFs). Generally speaking, low levels of sugar and insulin would suggest a lower risk of diabetes. And lower levels of IGFs would suggest a reduced risk of cancer.

During the study, the intervention group reported eating half as much fat and twice as much fibre, fruit and vegetables as their counterparts. Now, some misreporting may have gone on here. But as the authors themselves admit, even taking this into account the likelihood was that the diet of the intervention group was significantly different (supposedly ‘better’) than the diet eaten by those left to do their own thing.

And now to the results�

Compared to the non-intervention group, those eating the ‘healthy diet saw:

No significant reduction in insulin levels

No significant reduction in IGF levels

And in those with a body mass index of 25 or more, there was no significant reduction in glucose (blood sugar) levels either

In fact, the only benefit to be found was a statistically significant reduction in blood sugar levels in individuals with a BMI of less than 25.

But before we get too excited about this, let’s just see how big this reduction was. Usually, levels of glucose in the bloodstream will vary between about 4.0 and 6.0 mmol/litre of blood (mmol/L). The average decline in glucose levels in individuals eating the ‘healthy’ diet with a BMI of less than 25 was about 0.03 mmol/L. I calculate that to be a reduction in blood sugar levels of less than 1 per cent: not exactly what you’d call Earth-shattering.

Let’s not beat around the bush: this study seems to be just another example of the ineffectiveness of conventional ‘healthy’ eating. There is now plenty of evidence that the low-fat/high-carb paradigm does not deliver on its promises. One wonders what it will take for health professionals and politicians who promote this brand of eating to start reading the research and taking heed of it.


Flood A, et al.The effects of a high-fruit and -vegetable, high-fiber, low-fat dietary intervention on serum concentrations of insulin, glucose, IGF-I and IGFBP-3. European Journal of Clinical Nutrition 2008;62:186″196

13 Responses to Another study attests to the ineffectiveness of conventional ‘healthy’ eating advice

  1. Chris 7 March 2008 at 12:34 pm #

    Here is another one that seems at first glance to say similar things – a diet high in fruit, veg and whole grains (plus vegetable oil for stir frying) i.e. typical “healthy diet” – made these Chinese fatter!

    Any thoughts?

  2. Mike 7 March 2008 at 5:36 pm #

    If memory serves me, This idea that a high fruit diet is good for you came from health studies on a number of native tribes in Africa and other places.
    The thinking when somthing like. ‘Look at these people, they dont have all the problems we in the West have. It must be down to the diet of fruit they live on’.
    The problem with this thinking is, they didn’t measure the stress levels the tribal people didn’t have, and compare it with the stressed out hell we call life in the west.
    I wonder what the effects of being chased by a wild lion twice a year, would have on the health of the average Londoner. May be this is the link they are missing.

  3. Amy Dungan 7 March 2008 at 10:21 pm #

    “One wonders what it will take for health professionals and politicians who promote this brand of eating to start reading the research and taking heed of it.”

    I’d guess the answer is money. Money and prestige is what seemed to push the low-fat movement to the forefront of nutritional recommendations. I’d guess the only way that will change is if those in charge find a way to profit from the new message. (I’m not into conspiracies.. but this makes sense to me after all I’ve read on the subject. Especially after reading Gary Taubes Good Calories, Bad Calories.)

  4. Liz 8 March 2008 at 12:04 pm #

    Apropos of this I had occasion to look something up on the Food Standards Agency website the other day. Meandering around, I came across their healthy eating page and it reflects exactly this obsession with starchy carbs and low fat. The balanced diet is represented visually by a plate divided up in a “pie chart” way to show the different food groups.

    Where do they get this stuff from? This amount of starchy carb would serve us well if we were toiling in the fields all day long or walking 6 miles t’mill every day (and six miles back at night).

    Take a look at

    And weep.

  5. A 8 March 2008 at 8:06 pm #

    There was a huge shift in research focus when fat became demonized. Anyone in non-profit and academic research knows that researchers have to chase those grant dollars just to keep their labs going. It became very hard to get and keep grants if they didn’t find a way to make their summaries agree with the anti-fat/anti-sat fat dogma. Anyone who questioned the prevailing “wisdom” was ostracized (the dark side of the “peer review” system) and marginalized. Careers were ruined for those who stayed true to scientific skepticism. Careers blossomed to those who spouted the “party line”.

    My husband is a research scientist, funded by US NIH grants, so I have a nice ringside view of this circus (thank goodness he is in “basic” research and not nutrition, clinical, drug development, or industry research). At dinner parties and other gatherings of his colleages I regularly hear how people tweak their grant proposals to chase after whatever politically favored dollars are being thrown into the air – AIDS, breast cancer, prostate cancer, colon cancer, CVD, etc. I’m not saying that they are all doing anything unethical, just that the current system of “consensus science”, lack of research funds, and political influence sometimes brings out the worst in science. Scientists, after all, are human and have families and employees to support, too.

  6. The other (non-dietician)Kate 10 March 2008 at 12:23 pm #

    I just hit that link that Liz was kind enough to provide.
    The website is enough to make you weep. They are actually saying that a good healthy diet should be based upon starchy carbs.
    ‘Fat is bad. Carbs good’.

    They don’t even have the decency to discuss the merits of a restricted carbohydrate dietary approach.

  7. Dr John Briffa 10 March 2008 at 12:36 pm #

    I blogged about the FSA and its pro-carb approach last September. have a look (if you haven’t already had enough….)

  8. Hilda 10 March 2008 at 11:14 pm #

    It is so difficult to get people to understand what a healthy diet is as the Sugar Bureau controls info sent to professionals.They dont know that sugar is bad. THe leaflet read, ‘no upper limit for sugar consumption has been established’. I would say that the upper limit is none. OK if someones eats the odd choc fair enough but they should know that it is doing them no favours. The other big cherry is veg oil. People do not believe me when I say it is bad for us.

  9. Hilda 10 March 2008 at 11:17 pm #

    LIZ – I had alook at the eatwell plate. It really is about 60% carbohydrate as as well as the bread, pasta etc section, there is also the sweets section (more carbs) and the fruit/veg section which asre basically carbs too. NO wonder diabetes is so high.

  10. The other (non-dietician)Kate 11 March 2008 at 12:07 pm #

    There is a ‘contact us’ link, where you can email various people, but to complain about the content, they suggest the webmaster.

    Has anyone ever tried to do this and would it actually get them to amend their advice?
    I doubt it.

    I remember reading the dietician ‘Chris’, who used to come and object to Dr Briffa’s advice last year, writing that the advice was for people who were advised to change their diet. I suppose this ‘eatwell plate’ is a first step, but still, they could give low-carb diets a better and more balanced write-up.
    It’s been nearly 10 years of low-carbing for me.
    I felt so ill on the Ornish diet, despite Dr Ornish’s claims that it would cut my cholesterol levels – it didn’t – it increased them! What a relief to finally stop eating brown rice and beans and bread.

  11. bob 12 March 2008 at 10:57 am #

    One has to take this in context – it is a tool that you can use to teach people. It is not saying eat 60% carbs – then look at food portions.
    If we lived on one food group alone – say protein we would all be dead.

    In contrast look at the food pyramid nutritional therapists use – it says virtually the same thing except it seems to promote being vegetarian.

  12. Hilda 13 March 2008 at 11:32 pm #

    Bob I don’t know of any nutritional therapists who use this daft food plate and most are not vegetarians. Food pyramid IS saying eat 60% carbs as fruit and veg are seen as a separate category buut are really carbs. Dividing food up in this way is arbitrary anyway. If we were stranded on a desert island we would survive as many do without pasta, bread etc.

    I don’t think the eatwell plate is any sort of step. It is mad especially for diabetics.

  13. bob 19 March 2008 at 10:51 am #

    hilda – the food pyramid is the same but has no animal protein – it says eat 3 servings a day from grains etc.

    So are you saying as a nutr therapist you do not use it then. So what do you use to teach people – remember the plate is a teaching aid.

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