The UK ranked 23rd (127 deaths per 100,000), and the USA ranked 43rd (171 deaths per 100,000) after Rwanda and Nigeria (41st and 42nd).
That's different from obesity, say the researchers, as these are deaths not from overeating, but from nutritional imbalance in the diet - too much salt, or too few fruits, vegetables and whole grains.
Chris Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington, who led the study, claimed that the findings confirmed what people had believed for many years.
"Our assessment suggests the leading dietary risk factors are high intake of sodium [salt] or low intake of healthy foods", he said. "The countries with the highest rates of diet-related deaths were Uzbekistan (892 deaths per 100,000 people), Afghanistan, Marshall Islands, Papua New Guinea, and Vanuatu".
The study tracked trends in consumption of 15 dietary factors from 1990 to 2017 in a total of 195 countries.
An analysis of nearly 20 years of diet data from 195 countries found that poor diets killed 11 million people globally in 2017.
The global diet also included less than a quarter of the recommended amount of whole grains - at 29g average intake a day compared with the recommended 125g - and nearly double the recommended amount of processed meat - at around 4g average intake per day compared with the 2g recommended.
Perhaps not surprisingly due to their high omega-3 and fibre diet, Spain, Turkey and Bangladesh have some of the lowest number of diet related deaths.
The study also pinpointed the key elements of a healthy diet that not only prevents those deaths, but can actually actively protect consumers' bodies from the illnesses measured: nuts, seeds, seafood, fiber, fruits and vegetables.
The global intake of red meat was 18% greater than that considered optimal.
"The lack of fruit, vegetables and whole grains in diets across the world are very important - but the other dietary factor highlighted by this study is the high intake of sodium".
Authors of Thursday's study noted that economic inequality was a factor in poor dietary choices in many countries.