Thursday, July 3, 2014

Low GI Kiwi diet

Someone I know who eats a fairly standard Kiwi diet has been advised to lose some weight.  I have found eating low GI food has been really helpful for stabilising my weight.  This is because the sugar in low GI food is released to your bloodstream much slower than that in high GI food, so a low GI food will sustain you for longer than an high GI food that contains the same amount of calories.  I thought this person might find low GI eating helpful in achieving their weight-loss goal, but I didn't want to advise them to simply eat the way I do: my low GI eating occurs within the parameters of my preferred pseudo Asian/Indian diet, rather than a more 'normal' Kiwi diet.  Here is the background information on low GI eating I came up with, along with the pointers I came up with on how to lower the GI of a fairly standard Kiwi diet.  Maybe you'll find it helpful, too!

The GI of a food is a measure of how quickly your body breaks it down to get at the sugar.  The bigger the number (they're numbers out of 100) the faster the sugar gets into your bloodstream.  You want to aim at medium and low GI foods - the ones with the smaller numbers.  Anything under 55 is considered low, and 55-69 is medium.

Figuring out what's high/low GI isn't always intuitive: e.g. apricots decrease in GI when dried but for grapes it increases.  The GI of potato varies wildly depending on how it is cooked.  The scientists don't really know what causes a food to be high/low GI - they have to work it out empirically by testing it on people.

GI is to do with the starchy content of food.  All starch can be categorised low/medium/high GI but things with little/no starch (e.g. meat) just 'aren't' GI.

When you eat a meal, you'll be eating a bunch of things with different GI values along with some things that don't have GIs.  They all average out in your stomach, giving a 'glycemic load' (GL) for the meal.  This is basically obtained by multiplying the GIs of each ingredient by how much of that ingredient there was.

I've never bothered to figure out GLs of stuff I eat: instead I just try to make sure that the overall meal has a significant portion of low GI things in it, and if I'm eating something high GI like mashed spuds I'll try and balance that out by having something low GI like beans in the meal as well.

So, bearing all that in mind, here are my ideas on how you might try to modify your diet to decrease the GL of it overall.

breakfast

  • if you're eating toast, make it either from either Vogels or Burgen bread rather than the lighter bread you normally have.  Note that this bread goes mouldy faster than regular bread so you'll probably want to store it in the fridge.  All the breads in the Vogels and Burgen ranges are medium or low GI and they have lots of varieties so hopefully you can find some you like.
  • if you're eating Weetbix, substitute it for either Special K, oat-based muesli (if possible one with dried apricots rather than raisins in it) or porridge.  The porridge or muesli need to use oats that have just been rolled, not finely chopped.
lunch
  • if toast/bread, again use Vogels/Burgen.  Sourdough bread is also medium GI, so you could try that, too.
  • if you're having cheese on toast, at least sometimes have baked beans on toast instead.  All pulses (beans/lentils/chickpeas etc.) are low GI so that will make a really low GL meal.  Peanut butter on toast would also be good.
  • if toast and soup, make sure soup has some pulses in it, rather than just meat and vegetables.  For example use those bean soup mix packets when making vegie soup or do pea and ham soup rather than oxtail.
  • if doing sandwiches, make them in pita pockets rather than on normal bread.  You could also use the Vogels/Burgen bread but I personally don't much like it untoasted.
snacks
  • rather than biscuits, eat dried apricots for a sweet snack.  Note that most other dried fruits aren't low GI, so stick with apricots and particularly don't snack on dried pineapple, raisins or dates.  Oaty muesli bars are also good (I usually buy 'Nature Valley' ones), as are biscuits heavy in rolled oats such as ANZAC biscuits.
  • for a savoury snack, eat nuts.  All nuts are low GI.  Note that both nuts and dried apricots are quite high-calorie, so just eat a few - you should find them surprisingly filling because of their low GI rating.
tea/dinner
  • if having spuds, new potatoes are lower GI than old and waxy potatoes are lower than floury.  The GI is also lower if you eat them either boiled or baked (with the skin on) rather than mashed.  Kumara is medium GI so that's also good.
  • when you have rice, make sure it's always basmati rice (which is medium GI).  Most other white rice is high GI.
  • when you have pasta, make sure it's only just cooked (i.e. 'al dente'), rather than really soft.
  • when you have mince or stews, substitute beans/lentils for some on the meat.  This will lower the GL of the overall meal considerably.  Kidney beans are good in beef stews and you can use haricot/navy beans (two different names for the same thing) with lamb/mutton.  In mince you can mix in a tin of baked beans, or substitue up to half the mince with brown lentils.  You can buy brown lentils from Indian grocers.  Cook them for about 20-30 minutes in boiling water till soft then drain and throw in with the mince.  They freeze beautifully so you could cook lots and freeze them in small amounts if that's easier.

More info
The people who came up with the whole idea of GI are at Sydney University.  Their website has a newsletter with interesting information.  They also maintain a database of the GIs of all the foods ever known to have been tested, so if you're wondering where a food sits you can enter it into there and see what its GI is.  One of their people has also written heaps of recipe books and information books about this way of eating: you can see which ones Auckland Libraries stocks here.

Love,

--Heather :-)

2 comments:

  1. The GI concept makes a lot of sense, but some of the items above just scream "your sample size was too low - this is just noise". Sourdough bread is just bread - the starch is identical, the only difference is where the yeast came from. If that affects GI, then the claim that GL = Sum_i(GI_i*quantity_i) must be wrong - there must be food interactions. Alternatively, it's not that all sourdough bread is low GI, it's that _a particular_ sourdough bread is low GI. Either way, it's clear more research needs to be done on isolating what's really going on here, and ther'es not really enough info available yet to generalise the tests they've done in Sydney to a diet I might take up here in the UK.

    Definitely food for thought though.

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    Replies
    1. Sydney just maintains the database - the sourdough bread experiments were done in Canada, Italy and Sweden as well as Australia. Sourdough bread is different from regular bread in a number of subtle ways, not least that it has a lot of acid in it. Adding acid consistently lowers the GI of foods.

      --H :-)

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