US researchers say they have been able to show how it is possible to be a “bad vegetarian or a good non-vegetarian” by studying the quantities of ultra-processed food in a person’s diet.
Their study, which looked at the health impacts of both ultra-processed food and red meat consumption, is one of the largest of its kind, and involved over 77,000 participants.
The study, ‘Ultra-processed food intake and animal-based food intake and mortality in the Adventist health study-2’, published in the American Journal of Clinical Nutrition, assesses the mortality risks of two dietary factors independent of each other:
- The proportion of the diet composed of ultra-processed foods as opposed to less processed foods; examples of ultra-processed foods include soft drinks, certain meat analogs, and candy.
- The proportion of the diet from animal-based foods (meats, eggs, and dairy) as opposed to plant-based foods.
When the study authors adjusted their statistical model to focus on ultra-processed food intake irrespective of other factors like animal-food consumption or age, they found that people who obtained 50% of their total calories from ultra-processed foods faced a 14% increase in mortality compared to people who received only 12.5% of their total calories from ultra-processed foods.
The study found that high consumption levels of ultra-processed foods were associated with mortality related to respiratory, neurologic, and renal conditions — particularly Alzheimer’s disease, Parkinson’s disease, and chronic obstructive pulmonary disease (even when restricted to people who never smoked). However, high ultra-processed food consumption was not associated with mortality from cardiovascular disease, cancer, or endocrine conditions.
Results did not reveal an association between mortality and dietary intake of total animal-based foods. Once researchers parsed animal-based foods into sub-categories, however, they found a statistically significant 8% increase in the mortality risk associated with moderate (approximately 1 ½ oz per day) consumption of red meat compared to no red meat.
“Our study addresses the question of what can make a vegetarian diet healthy or unhealthy. It seems that the proportion of ultra-processed foods in someone’s diet is actually more important with respect to mortality than the proportion of animal-derived foods they eat, the exception being red meat”
Study author Gary Fraser, MBChB, PhD, a study author, and professor at Loma Linda University School of Medicine and School of Public Health, said: “Our study addresses the question of what can make a vegetarian diet healthy or unhealthy. It seems that the proportion of ultra-processed foods in someone’s diet is actually more important with respect to mortality than the proportion of animal-derived foods they eat, the exception being red meat.”
Fraser says the study exposes how it is possible to be a “bad vegetarian or a good non-vegetarian” because it isolates the health impacts of processed foods in the diet — whether it’s vegetarian or not. Results revealed that vegetarians who ate a lot of processed foods as part of their diets faced a similar proportionate increase in mortality outcomes as non-vegetarians who ate a lot of processed foods in their diets.