Examples include chicken nuggets, preserved meat products, packaged snacks and instant noodle soup meals.
Study participants provided information about their eating habits, lifestyle, and socio-economic background before having their progress monitored for seven years.
During the follow-up period researchers recorded 602 deaths, including 219 deaths caused by cancer and 34 by heart and artery disease.
The scientists, led by Dr Laure Schnabel from Paris-Sorbonne University, wrote in the journal Jama Internal Medicine: «An increase in ultra-processed foods consumption appears to be associated with an overall higher mortality risk among this adult population.»
Consumption of ready meals and other forms of ultra-processed food accounted for an average 29 per cent of total calorie intake, the study found.
It was also associated with younger age, poorer education, living alone, lower physical activity and higher body weight.
There could be several explanations for the findings, the scientists said.
Some ultra-processed foods contained large amounts of salt, and high sodium intake had been associated with higher rates of cardiovascular disease and stomach cancer.
Excessive sugar in the diet was also linked to a greater risk of cardiovascular disease death.
In addition ultra-processed foods contained little fibre, which had been shown to reduce mortality risk.