The study revealed a worldwide rise in the consumption of healthy food, including fruit and vegetables, but this was overtaken by a worrying increase in the amount of junk food being eaten.
To make their findings, published in ‘The Lancet Global Health’ journal, researchers used national data from almost 90 per cent of the global population to analyse how people ate between 1990 and 2010.
They then assessed three dietary patterns. The first was based on ten healthy foods: fruits, vegetables, beans and legumes, nuts and seeds, whole grains, milk, total polyunsaturated fatty acids, fish, plant omega-3s, and dietary fibre.
The second was based on seven unhealthy foods: unprocessed red meats, processed meats, sugar-sweetened beverages, saturated fat, trans fat, dietary cholesterol, and sodium. The third was an overall assessment based on all 17 food groups.
Using this data, researchers scored countries between 0-100 – with a higher number indicating a healthier diet.
The study revealed that high-income nations, such as the US, Canada, Western European nations, Australia and New Zealand, had better diets based on healthy items but substantially poorer diets when unhealthy food was considered.
And countries in sub-Saharan Africa and some Asian nations, including China and India, saw no improvement in their diets over the past two decades.
Meanwhile, low-income nations, such as Chad and Mali, scored best for healthy foods.
Scoring lowest for healthy foods were European countries including Belgium and Hungary and republics of the former Soviet Union – including Uzbekistan, Turkmenistan, and Kyrgyzstan.
When age and sex were assessed, researchers found that older people ate better than younger adults, and women ate better than men.
Researchers hope that their findings can help nations reduce the health and economic risks of poor diets.
Dr Fumiaki Imamura, of the University of Cambridge, who led the research, said that improving diet has a “crucial role to play” in reducing the burden of non-communicable diseases, which will account for 75 per cent of all deaths by 2020.
The countries with the healthiest diets overall were:
2. Sierra Leone
7. Ivory Coast
The countries with the least healthy diets overall were:
4. Czech Rebublic