Fat tax would add $1 to butter
A fat tax is being suggested as a possible way to improve the health of New Zealanders by encouraging people to replace some saturated fats with polyunsaturated fats.
Some butter could be replaced with grapeseed or safflower oil, meat with omega-3 rich fish, and potato chips with nuts or seeds, while the tax could add $1 to a pack of butter.
Rachel Foster and Associate Professor Nick Wilson from Otago University in Wellington looked at five meta-analyses to estimate how the risk of cardiovascular disease could be reduced by eating less saturated fats.
They also used data from the New Zealand Adult Nutrition Survey 2008/09 to determine whether a change to the amount of fat eaten would be warranted and feasible.
Their conclusion was that replacing 5 per cent of daily energy consumed as saturated fat with polyunsaturated fats would be expected to reduce cardiovascular events by about 10 per cent.
On average New Zealanders were getting almost 34 per cent of daily energy as fat including 13 per cent as saturated fat. That compared to recommendations that dietary intake of fat be no more than 30 to 35 per cent of daily energy, with less than 10 per cent of daily energy from saturated or trans fats, the study said.
Many New Zealanders were not eating enough polyunsaturated fat, with an average intake of 5 per cent of daily energy, compared to recommended levels of 6 to 11 per cent.
The study, published in the Australian and New Zealand Journal of Public Health, said the proposal would, on average, mean men replacing 14g of saturated fat and women replacing 10g.
Examples of how that might be done included replacing two tablespoons of butter with two tablespoons of grapeseed or safflower oil, or 65g of cheddar cheese with 30 to 60g of walnuts or sunflower seeds.
"The changes that would be required to dietary habits would seem to be attainable for most people," the study said.
While the meta-analyses used in the study found benefits from replacing saturated fats with polyunsaturated fats, they did not find any significant association between saturated fat intake alone and cardiovascular disease. Replacing saturated fat with carbohydrates also did not reduce the risk of coronary events.
"The top sources of saturated fats in New Zealand are butter and margarine, milk, bread-based dishes, cheese, and cakes and muffins. Most of these are readily amenable to substitution with lower saturated fat and, in most cases, higher PUFA (polyunsaturated fatty acids) products or ways of cooking."
Looking at how to achieve a permanent 5 per cent substitution of saturated fats, the researchers said education alone was unlikely to be sufficient.
The effectiveness of a saturated fat tax would depend on the size of the tax, the price changes that resulted, and the extent to which consumers would buy less food high in saturated fat. To be effective, the amount of polyunsaturated fat eaten needed to increase.
Before a Danish-style saturated fat tax was introduced, further research was needed on quantifying the likely benefits, the costs, and cost-effectiveness.
The study noted the tax on saturated fat in Denmark only lasted a year, apparently due to concerns about job losses and the effect of cross-border shopping in Germany and Sweden. If such a tax was applied in this country, it would increase the cost of a 500g pack of butter by about $1.
Further research on a saturated fat tax would allow comparisons to be made with alternative interventions, such as taxes on other hazardous food components such as sugar and salt, or on categories of unhealthy foods that were high in salt, sugar and saturated fat.
A policy package could provide subsidised vegetable oils high in PUFAs for low-income people, maybe through targeted smart cards for specific food products, or the funding of healthy school meals by central government.
Comparisons could also be made with regulations to set maximum saturated fat levels allowed in foods, mass media campaigns to improve diets, and improved nutrition labelling of food.