Although humans are living longer than ever before, one in five deaths last year were linked to poor diet, according to the most comprehensive study ever carried out on the subject.
Millions of people are eating the wrong sorts of food for good health. Eating a diet that is low in whole grains, fruit, nuts and seeds and fish oils and high in salt raises the risk of an early death, according to the huge and ongoing study Global Burden of Disease.
One bright spot was the better-than-expected health performance of several countries, including Ethiopia, the Maldives, Nepal, Niger, Portugal and Peru, which made outsized improvements in relation to national wealth, or GDP. India was not on this list.
The study, based at the Institute of Health Metrics and Evaluation at the University of Washington, compiles data from every country in the world and makes informed estimates where there are gaps.
It says more than 1.6 million people in poor countries died in 2016 from diarrhoea caused by contaminated water and food, while another 2.4 million succumbed to lung infections that mostly could have been prevented or treated, researchers said today.
Another two million mothers and newborns perished due to complications at birth that rudimentary health care could have largely avoided.
Somewhat paradoxically, the study also finds that people are living longer. Life expectancy in 2016 worldwide was 75.3 years for women and 69.8 for men. Japan has the highest life expectancy at 84 years and the Central African Republic has the lowest at just over 50. In the UK, life expectancy for a man born in 2016 is 79, and for a woman 82.9.
Diet is the second highest risk factor for early death after smoking. Other high risks are high blood glucose which can lead to diabetes, high blood pressure, high body mass index (BMI) which is a measure of obesity, and high total cholesterol. All of these can be related to eating the wrong foods, although there are also other causes.
AIDS and tuberculosis each claimed more than a million lives, while malaria killed over 700,000 people, according to half-a-dozen studies published jointly in The Lancet, a leading medical journal.
But trend lines have declined over the last decade for these communicable diseases.
The same cannot be said for viral hepatitis, which killed 1.34 million people in 2016 - 22 per cent more than in 2000, according to the World Health Organization.
"Hepatitis deaths can be avoided," said Raquel Peck, CEO of World Hepatitis Alliance, pointing out that no global facility exists to combat the disease and that most sufferers don't even know they have it.
"Globally, only 5 per cent of people living with viral hepatitis are aware of their condition."
Nearly three quarters of all deaths in 2016 were caused by non-communicable diseases, with heart disease related to restricted blood flow the single biggest killer of all, accounting for 9.5 million deaths. That's an increase of nearly 20 per cent in a decade.
Similarly, mortality due to another so-called "lifestyle" disease, diabetes, went up by more than 30 per cent over the same period to 1.4 million.
Cancers - led by lung cancer - are also on the rise, accounting for nearly nine million deaths in 2016, 17 per cent more than in 2006.
Tobacco is blamed for 7.1 million of those fatalities.
Startlingly, the study finds that, combining the two extremes of inadequate nutrition in poorer countries and unhealthy eating in richer communities, poor diet is linked to one in five deaths worldwide.
"Among all forms of malnutrition, poor dietary habits - particularly low intake of healthy foods - is the leading risk factor for mortality," researchers concluded.