The research tracked trends in consumption of 15 dietary factors from 1990 to 2017 in 195 countries.
Consuming too much salt and too few whole grains were found to be particularly fatal, with each being responsible for three million deaths.
The causes of these deaths included 10 million deaths from cardiovascular disease, 913,000 cancer-related deaths, and nearly 339,000 deaths from Type-2 diabetes.
Research carried out by Dr Christopher Murray, Director of the Institute for Health Metrics and Evaluation, University of Washington in the USA has found that Israel has the world's healthiest diet, or to be more precise, the world's least unhealthy diet.
Prof Murray also said that as well as knocking a couple of years off of life expectancies, people should also be aware of the greater risk of disease such as cancers and heart attacks because of poor diet. "We are what we eat and risks affect people across a range of demographics, including age, gender, and economic status", said lead author Ashkan Afshin, Assistant Professor at the varsity.
What's driving this? As a planet we don't eat enough healthy foods including whole grains, nuts, seeds, fruits and vegetables.
It found that on average, reaching the "five-a-day" fruit and vegetable servings advocated by doctors cost just two per cent of household income in rich nations, but more than a half of household income in poorer ones.
United States co-author Professor Walter Willett, from Harvard University, said the findings supported recent research on heart and artery disease that advocated replacing meat with plant protein.
But now research shows that your diet could be far more likely to put you in an early grave than tobacco.
The authors note several important limitations to the study. "This concept of increasing intake of healthy food should be added to current policy debates for improving diets", he said.
Vegans can find omega-3's in certain nuts and seeds including flaxseed, chia seeds, hemp seeds and walnuts, and can also take an algae-based DHA supplement to meet their omega-3 requirements.
"We call on governments to implement evidence-informed policies that encourage people to make healthier choices by making the healthy option easiest".
The most recent analysis evaluated the consumption of major foods and nutrients across 195 countries and the impact of suboptimal intake on mortality and morbidity.