Resistant Starch: Misunderstood and Mis-promoted

Men’s Health has a good reputation so HolfordWatch was disappointed to come across: Shrink Wrapped: Strip fat with our precision engineered bangers and mash. The article is a good example of a dietary recommendation that is based on a reasonable premise but is badly communicated and promotes confusion.

The writer claims that:

There’s no need to ditch the spuds…Recent University of Colorado research shows spuds have a lean secret: they’re a source of resistant starch. Studies show resistant starch’s bulk makes you feel full, but as it “resists” digestion its calories don’t get into your bloodstream. Instead, it ferments in your large intestine creating beneficial fatty acids. “This can prevent the liver from using carbs as fuel and turn to burning stored body fat instead,” says Dr Janine Higgins, nutrition research director at the University of Colorado…

The spuds
Are you ready for some culinary alchemy? Follow these simple instructions and these humble spuds will soon be transformed into nutritional gourmet gold. Start by peeling the potatoes. It doesn’t matter whether you opt for standard slim-down spuds or carb-loaded bulk-up sweet potatoes; they both get the same treatment. Chop them into 2.5cm, even-sized chunks. Rinse the chunks in water to remove excess starch. Now fill a pot with enough water to cover them, throw in a big pinch of salt and boil over medium high heat until soft. This should take about 12 minutes…

Drain the spuds, mash, add the vegetable or chicken stock and mix well. Season to taste, spoon onto your plate and top with gravy…Salivate freely and prepare to tuck in.

Now, the essential point of information that is missing from these instructions is that the mashed potatoes would have to be allowed to go cold (even chilled in the fridge) for there to be measurable resistant starch[a]: even so, that would yield a whole 2.4g per 100g (pdf) (boiled potato – it may be even less in mashed). For those who wish to increase their intake of resistant starch, it might have been better to advise that the potato is mashed together with chickpeas, butter beans or haricot beans.

Resistant starch, glycaemic index and glycaemic load are popular stories in mainstream media but they are too frequently covered incorrectly or parrot the press release nutritionism of nutritionistas. Who can forget the claim by Patrick Holford’s frequent co-author, Fiona McDonald Joyce, that chicken breast has a higher glycaemic load than chicken thigh or drumstick (chicken has a negligible carbohydrate content unless it has been breaded, marinaded in particular dressings etc.)? Like resistant starch, the full and appropriate detail about glycaemic index or glycaemic load as a guide to a sustainable way of eating it too rarely given in mainstream media: there is too much glib coverage from excited journalists who follow a diet for a few days and feel that this qualifies them to comment on it.[b] Such writers should ponder the recent diet experiment in Professor Regan’s Clinic currently showing on BBC2.

I developed my own diet pill and asked 17 overweight people to try it for a month, alongside a balanced diet and a sensible exercise plan.

More than 70 per cent of the volunteers lost weight and believed the tablets had worked. Unbeknown to them, though, the tablets were simply sugar, a placebo – which shows the power of mind over matter. Yet I could easily use my results to launch an impressive marketing campaign, – as many companies do.

In the television programme, several of the participants spoke about their reduction in appetite and their increased feelings of energy.

Whether it is the over-hyped properties of resistant starch or glycaemic index or load, this is what is so remarkably tiresome about so much of the mainstream media coverage of nutrition – a fairly sensible, simple message is garbled to the point where it is distorted to the point that it is unrecognisable. Any confusion is then blamed on ‘scientists who can’t make up their minds’ when the blame belong solely (as with Men’s Health) with the distortion of the self-styled intermediary. That sounds awfully familiar and drearily ubiquitous.


[a] For those who are agog for more information, we recommend Garrow et al.’s Human nutrition and dietetics.

Resistant Starch (RS) is defined…as the starch (and starch degradation products) that escapes digestion in the small intestine and becomes available for fermentation by the microflora in the large intestine. RS may be measured as a single fraction of starch or subdivided into RS1, RS2 and RS3. Physically inaccessible starch, which may be found in whole or partially milled grains or seeds, and in some very dense types of processed starchy foods, e.g. pasta, is RS1. Starch that escapes digestion in the small intestine because the granules in, for example, raw potato and banana starch, are intrinsically highly resistant to hydrolosis by pancreatic amylase is RS2. The third category, RS3, is mainly retrograded amylose formed during the cooling of gelatinized starch. Most moist-heated starchy foods will therefore contain some RS3 upon cooling.

The textbook gives a good overview of the variation in RS in various foodstuffs and for individuals.
[b] The journalist in question has obviously failed to browse this site if s/he thinks that our criticisms are solely of Patrick Holford’s methods and qualifications:

Holford does have his detractors. There’s even a website, Holford Watch, which is full of criticisms of his methods and qualifications.

We have expressed ourselves at some length on the issues of Holford’s mis-communication of research findings, errors in basic science and flawed scholarship.


Filed under blood sugar, GL diet, glycaemic load, glycemic load, Low GL Diet

2 responses to “Resistant Starch: Misunderstood and Mis-promoted

  1. Highway Kind

    I’m not sureMen’s Health is that great; it is published by Rodale who promote this sort of dietry nonesense in all their magazines. Runners World for example always has a large section on food and nutrition.

    I would be happy if they just presented a some recipes and said here is some good tasty food that you might like to try. Instead they feel compelled to say that it comes from the latest research and is the scientific way of eating for peak performance etc etc.

    When we buy these magazines we are already invested in the idea of getting stronger and running faster. We are looking for tips that might help and diet is seen as something that can make a difference. Unfortunately that leads to the spurious quest of classifying every foodstuff as either good or bad, better or best, according to the latest press release that crosses their desk

    • Fair enough – I suppose it’s by comparison to the standard of women’s magazines, as glimpsed in dentist waiting rooms etc. that Men’s Health looked OK. I suppose the problem for all periodicals is that ‘new science’ and ‘new discoveries’ sell – the familiar and well-established doesn’t.

      Agreed on the annoying classification of foodstuffs.

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