Life is as complex as food labelling systems

The International Consensus Summit on Glycemic Index, Glycemic Load and Glycemic Response called for this because of the physiological effects of different carbohydrates on blood sugar, which affect the risk of developing type 2 diabetes and heart disease.

At the same time, another project by The Institute of Fiscal Studies, part-funded by the UK government, found that although there had been a 20% fall in calories consumed over the 30 years up to 2010, the weight of the average person has increased by 0.25kg a year. This was deemed to be only partly due to lack of exercise. It indicated that the diet had become more loaded with takeaway foods.

What a pity the Department of Health (DH) did not wait for these research results before introducing the front-of-pack labelling initiative. Now, those consumers who look at a list of glycaemic loads (GLs) for common foods could be confused because some carbohydrate foods with high GLs are among those that the DH is encouraging people to eat more of. Many of these, such as rice and potatoes, being single-ingredient foods, will not be labelled with traffic lights and people may be less aware of the dangers of eating too much of these. Had the colour coding been based on GLs, foods like these would have had red traffic lights.

Similarly, dairy products such as milk and yogurt, which qualify for amber traffic lights under the DH system would be green under GL criteria. Although the majority of common foods with red or green lights under the DH system would be similarly coloured under a GL labelling scheme, the latter has the advantage of being relative to recommended portion sizes rather than the misleading per 100gm. GL labels could have included the portion size in brackets, eg peanut butter GL1 (16gm).

Advice to consumers on healthy diets might have been a lot simpler using a GL scheme and, arguably, more accurate. Although most of the foods on the naughty but nice shelves would be red under both schemes, foods misleadingly categorised as red or amber under the DH scheme would be more correctly green, according to GL.

 Simple advice to consumers would be to base most of their diet on the green GLs and eat the reds sparingly. Foods containing no carbohydrate, such as meat, fish and dairy, have zero GI so separate and simple advice could be given on packs of these as to healthy portion sizes, rendering traffic lights redundant. But life is not so simple!