Food digestibility as important as ingredients, research shows

Ultra-processed foods contributing to human health problems, says UG professor

By Lilian Schaer for Livestock Research Innovation Corporation 

New research from the University of Guelph shows that how the body digests food is as important as what it’s made of. A piece of a plant-based meat alternative might look and taste like meat, but that doesn’t mean it has the same impact on the human body as the real thing. 

This has consequences for overall human health, says Prof. Michael Rogers, a Tier Two Canada Research Chair in food nanotechnology and associate professor in the University of Guelph’s food science department who led the research.

“We’re seeing an entirely new epidemic of metabolic syndrome and we see the prevalence of this syndrome, which includes obesity, high blood pressure and diabetes, increase whenever a population introduces new ultra-processed foods,” says Rogers.  

He believes what he calls the disturbing trend of displacing minimally processed foods – like meat – with products that are ultra-processed to be a significant contributor to the problem. Ultra-processed foods are ones made from ingredients extracted from whole foods, formulated to be tasty, low cost, convenient and have a long shelf life. 

Rogers and Ph.D. candidate Zhitong (Zoe) Zhou compared how the body digests a plant-based meat product and an actual meat product. The project used a Beyond Beef burger and a burger made of real ground beef, but the findings are equally applicable to plant-based chicken alternatives and chicken meat, he notes. 

They found that the human body more quickly and easily digests a plant-based burger than a meat burger. This leads to rapid fat digestion and ultimately a higher lipemic index (equivalent to the glycemic index for carbohydrates), which is an important biomarker for cardiovascular health. 

In addition to lipids, the plant-based burger contains significant amounts of starch, which is capable of increasing blood sugar levels, whereas a meat patty contains no carbohydrates, so it doesn’t impact blood sugar levels.

“Meat is a complex protein network that entraps fat, so it takes the body longer to access and digest or break down that fat. This releases nutrients more slowly into the body, potentially altering feelings of fullness for a longer period after eating,” explains Rogers. “When you formulate a plant-based burger, the fat can’t be bound the same way as it is in meat, so it breaks down more quickly. That’s a major limitation to current ultra-processed food technologies.”

Although the food industry has done a remarkable job of creating many processes to turn perishable whole food commodities into self-stable ingredients such as oils, starches and protein isolates, Rogers believes more needs to be done to formulate them into ultra-processed foods that also resemble whole foods while they’re being digested.

“People need to change their thinking around ultra-processed foods. Just because something is plant-based, doesn’t make it healthier,” Rogers says. 

Part of the challenge is that only about two percent of Canadians are involved in farming leaving most people with little understanding of food and how it is produced. This spills over into environment and climate change issues: there is little appreciation for the key role that livestock play in carbon sequestration and being able to use land for food production that isn’t suitable for growing crops. 

“A two-class food ecosystem is emerging in Canada, where only a subset of Canadians can afford the time and cost to follow Canada’s Food Guide recommendations to prepare meals from scratch and to avoid ultra-processed foods; this will become a problem for Canada moving forward,” Rogers says. 

Rogers’ research was supported by Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery and Canada Research Chair Programs. A webinar where Rogers presents his research in more depth is available.

This article is provided by Livestock Research Innovation Corporation as part of its ongoing efforts to report on research developments and outcomes, and issues affecting the Canadian livestock industry. It was published in the April 11, 2023 edition of the Ontario Farmer.