KFC announced on Monday that it was changing its frying oil to eliminate trans fats from its main meals in the USA. Monday as it happens was also the day the New York City Board of Health began a public hearing on whether restaurants in New York should be banned from selling foods with trans fats on the grounds that they increase the risk of heart disease and have no nutritional value. But the pressure has been building up for some time.

Labelling regulations in the US have changed, forcing manufacturers to own up to how much trans fat - produced by partial hydrogenation of industrial oils - is in their products. A retired doctor had also filed a class action four months ago against the company for selling food with trans fats without telling its customers. The lawsuit was supported by the campaign group, Center for Science in the Public Interest (CPSI), which greeted KFC's news as an important milestone and announced it will now withdraw its lawsuit. So that's a victory for public health and consumer power then.

CSPI has certainly achieved remarkable progress in the US. But KFC is not changing its recipes in the UK where it uses partially hydrogenated rapeseed oil, although it says it has been researching new fats here. Not enough lawsuits perhaps. Nor does the KFC website for the UK tell customers how much trans fat is in its products, although it tells me it will during 2007. You have to go to the UK campaign group Which? for the information that a KFC meal contains 4.4g of trans fat according to its analysis.

And here's a curious thing. KFC in the US is switching from partially hydrogenated soya oil to a new low-linolenic soya oil. The new low-linolenic soya oil has only 3% alpha-linolenic acid compared with 8% in standard soya oil. That alpha-linolenic acid is the omega-3 fatty acid that is pretty short in the industrialised diet and most of us could do with more of it rather than less. But it's a bore to manufacturers because it's unstable. Hydrogenating was one way to deal with it, engineering it out of the bean is another. And yes, you've guessed, the new low-linolenic soy oil for KFC comes from a soya bean developed by biotech giant Monsanto.

Monsanto's website explains how this new soybean, called Vistive, is now being planted in large tracts of the American mid-west "to help manufactures reduce the presence of trans fatty acids in their products". Vistive, its says, was "developed through conventional breeding". A puzzle then that Vistive soybeans also have the trademarked GM Roundup Ready trait so that they can be sprayed with the company's herbicide glyphosphate.

If you want to know how a new transgenic soybean can manage not to be a new genetically engineered soybean, have a look at another campaign website, the anti-GM Institute of Science in Society.

But here's the real conundrum. Thanks to subsidies and the muscle of large US-based food multinationals, 20% of available calories in the US now come from soy oil. Experts such as Joseph Hibbeln at the US government's National Institutes for Health believe this unprecedented change in our diets is not only responsible for cardiovascular disease but is changing the architecture and functioning of the brain.
http://lifeandhealth.guardian.co.uk/health/story/0,,1924356,00.html

His theory is that the dramatic rise in omega-6 fatty acids mainly from oils such as soya, have flooded out the omega-3 fatty acids we need to build the brain, as well as for vascular health, because they compete for the same metabolic pathways.

If he's right, companies like KFC are leaping out of the fat straight into another oil-fuelled fire. But don't worry Monsanto is on the case. It has another new modified soya bean in the pipeline - Vistive omega-3, due to become available around 2011-2013. Perhaps they hope customers won't have noticed this other problem before then. It's taken over a decade for progress on trans fatty aids after all.

There is of course another simpler way - just stop eating so much industrial oil, full stop. But then KFC couldn't sell so much fried chicken.