Comments on: Tom Wolever on carbohydrate quality

By: Bill Shrapnel

Bill Shrapnel — Sun, 13 Oct 2013 04:40:50 +0000

Hi Kelly. You have put your finger on one of the key issues confronting nutritionists at present. Now that we know that carbohydrate is no better than saturated fat in relation to heart disease risk, the emphasis is turning to carbohydrate ‘quality’. We should be recommending that people eat good quality carbs, and less poor quality carbs. But currently there is no agreement on what comprises good and bad carbs.
GI is ONE dimension of carbohydrate quality but it is often criticised because it endorses the use of some foods that are nutrient-poor. I think the concepts of GI and nutrient density should be considered together and this is exactly what Manny Noakes and I did in our carbohydrate quality model, which is discussed elsewhere in this blog. If a food is nutrient-rich + low GI – that’s great. If a food is either nutrient-rich or low GI – that’s OK. But if a food is both nutrient-poor and has a high GI, what has it got going for it? Nothing! To my mind these are the carbohydrate-foods we should be limiting in our diet. But these foods don’t necessarily contain sugar. White rice is a good example of a nutrient-poor, high GI food that still appears on healthy eating guides. Who knows why? It’s consumption increases the risk for diabetes! Regards, Bill

By: Kelly

Kelly — Tue, 01 Oct 2013 00:51:08 +0000

Hi Bill,
Currently looking into GI foods. I enjoyed this article, but just wondering if you know of any studies that have looked into whether or not GI is a good indication of a ‘healthy’ food? For example, because peanut M&M’s have a low GI, does this mean they are a healthy food? To me, no it doesn’t, but I can’t find any research that has looked into this idea.
Thanks,
Kelly.

By: Bill Shrapnel

Bill Shrapnel — Tue, 28 May 2013 00:30:38 +0000

Hi Michelle.
The term ‘superfood’ is absurd yet the lay media almost demands its use, especially if you want publicity for a book. In this morning’s paper I read about an American ‘nutritionist’ who ‘champions superfoods such as goji berries, hemp seed and blue-green algae’. So he gets his photo in the newspaper and the opportunity to promote his book. Unfortunately, he also advocates raw foodism which he describes as a ‘great cleansing protocol’. People following his advice may get ‘cleansed’ in a way they didn’t bargain for. I hope nobody dies.
Regards, Bill

By: Michelle

Michelle — Mon, 27 May 2013 03:47:03 +0000

“Sometimes the acceptance of new approaches in science proceeds slowly, funeral by funeral.” Such a great sentence, and such an irritating side effect of tenure.

I found your blog today – I am a 20-something female and it is so refreshing to see a sensible, scientific approach to nutrition, especially in comparison to the multitude of blogs written largely by other 20-something females with no qualifications or even a rudimentary understanding of how science works (no, a fashion magazine list of “superfoods to try” is not an acceptable source). Thank you for redeeming my faith in the term “nutritionist”.

By: Bill Shrapnel

Bill Shrapnel — Mon, 27 May 2013 00:25:23 +0000

Hi Paul
In our model we included dietary fibre in our calculation of nutrient density, on the grounds that if it had an NRV it should be included (Drewnowski’s rationale). Thus wholegrains were assessed according to the sum of their parts – essential nutrients and fibre (and didn’t rate very well on those grounds).
Some people have argued that this elevated fibre too highly, giving it equal weight to thiamin. Others argued that fibre was the key to protection against chronic disease by cereal foods. Paul, you seem to fall in the latter camp. But are you saying that glycaemic response is not associated with risk? Regards, Bill

By: Paul Rogers

Paul Rogers — Sun, 26 May 2013 23:19:10 +0000

Another model might be total dietary fibre, with less concentration on GI or whole grains. At around 0.5 gm/kg/bw/day and above, I would be surprised if targeting GI or whole grains made much difference to diabetes or CVD risk — other factors being equal.

By: Bill Shrapnel

Bill Shrapnel — Thu, 23 May 2013 07:12:26 +0000

Totally agree Kate. That’s why Manny Noakes and I included both GI and nutrient density in our carbohydrate quality model. Carbohydrate quality is not a black/white issue – there is a fair bit of grey in the middle. Sooner or later we will have to decide which combination of parameters is best. Anything would be better than the starch/good, sugar/bad paradigm which hasn’t really changed in my 32 years as a dietitian, despite there being little evidence to support it. Maybe it will happen in your professional lifetime! Regards, Bill.

By: Kate

Kate — Wed, 22 May 2013 04:47:06 +0000

This is an excellent debate! I personally have a love/hate relationship with the glycemic index. While I think it is another way to measure the quality of carbohydrate foods, it also presents a way for food manufacturers to make some less-than-healthy foods appear more-so. In my own practice, I often find that people may choose a lower quality food, for example a low GI sweet biscuit, as a snack instead of fresh fruit or perhaps more quality carbohydrates merely because of the GI. I think that’s the wrong message. We need to look at the total diet. The emphasis should be on total diet quality, and GI is just one (albeit flawed) measure of quality.