“We wanted to make a health-based evaluation of the beneficial and detrimental impacts of the food in the entire diet,” Olivier Jolliet, professor of environmental health sciences at the university and senior author of the paper, told CNN.
The team came up with an index that calculates the net beneficial or detrimental health burden in minutes of healthy life associated with a serving of food. It’s based on a study called the Global Burden of Disease, which measures morbidity associated with a person’s food choices.
“For example, 0.45 minutes are lost per gram of processed meat, or 0.1 minutes are gained per gram of fruit. We then look at the composition of each food and then multiplied this number by the corresponding food profiles that we previously developed,” Jolliet said.
One of the foods researchers measured was a standard beef hot dog on a bun. Its 61 grams of processed meat resulted in the loss of 27 minutes of healthy life, Jolliet said — but when ingredients like sodium and trans fatty acids were factored in, the final value was 36 minutes lost.
Consumption of foods such as nuts, legumes, seafood, fruits and non-starchy vegetables, on the other hand, have positive effects on health, the study found.
The index looks at foods that increase or decrease life expectancy, but it’s not as easy as trying to cancel out detrimental food choices with more beneficial ones, Jolliet said.
“The index is primarily there to help aid in selecting and using calories consumed on a daily basis to tweak a minimum of habits and make the minimum of change to obtain a maximum benefit for health and the environment from our food experience,” Jolliet said.
The point is to choose better foods, not to spend time doing the math, he said.
“Is it the ultimate metric that will tell you exactly what to eat tomorrow and entirely determine your life expectancy? No,” he said. “It is a useful metric that can help you make more informed choices and makes it simpler to identify and make adequate small changes in our diet.”
It’s also not as easy as calculating what food to eat in order to live to be 100, said Marion Nestle, a professor of nutrition and public health at New York University. She told CNN the numbers may not be entirely reliable.
“Changing a diet to include or exclude any one food is unlikely to make much difference — it’s dietary (and lifestyle) patterns that count,” she said. “I suppose you could argue that the minutes add up, but that gets into further untested and untestable assumptions.”