Why does preserving the food matrix make a difference?
How Ultra-Processed Foods Could Cause Disease: Changes in Structure
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In the past few videos, I covered the nutrient profile of ultra-processed foods, the industrial contaminants, the additives––both intentional and unintentional––as well as changes in texture. But what’s this about food matrix?
In the famous study that found that ultra-processed diets caused excess calorie intake and weight gain compared to unprocessed diets––despite the fact that both diets were matched for calories, sugar, fat, and fiber, suggesting that it may be something about the processing itself, such as the concentration of calories and the changes in texture that allow for the foods to be eaten so much faster. But wait. How did the researchers match for fiber? It’s hard to imagine ultra-processed foods having much fiber.
Here are two representative dinners. On the ultra-processed side, nonfat yogurt, fruit in heavy syrup, baked potato chips, a deli meat and cheese sandwich, and three cups (720 ml) of diet lemonade. And with the same amount of calories, fat, and sugar on the unprocessed side, a Southwestern entrée salad with greens, beans, nuts, fruits, and vegetables. How could the ultra-processed meal possibly have the same amount of fiber? What they did was sprinkle a fiber supplement in the yogurt and lemonade. So technically, both meals had the same amount of fiber. But that’s not how fiber works.
A half century ago, the dietary fiber hypothesis was proposed, suggesting that fiber was the reason that diets centered around whole plant foods were so protective against chronic disease. Predictably, this gave rise to a multibillion-dollar fiber supplement market. People could just eat real food, but where’s the money in that? (Of course, it’s hard to trust projections from internet press releases. I highly doubt the fiber market is going to hit 20,000 million billion.)
Those who get more fiber in their diet are significantly less likely to get heart disease, strokes, and diabetes, and less likely to die from cancer and all causes put together, but that’s with fiber from food. In terms of fiber intake for optimal health, the first line of defense for disease prevention is to focus on fiber from foods rather than supplements. For the treatment of disease, there is a lack of evidence-based research to support the use of most isolated fiber types. You can’t just take your magic bullet of Metamucil with your Wonder Bread. That’s not how fiber works.
Dietary fiber alone has certain benefits, but its primary role may be the physical encapsulation of nutrients inside the cell wall for special delivery to our gut microbiome. Fiber makes up the cell walls of plants, which act as an indigestible physical barrier. So, when we eat structurally intact plant foods, many of the nutrients remain trapped. Chew all you want—you’re still going to end up with nutrients completely surrounded by fiber, which then blunts the glycemic response, activates a natural satiety mechanism called the ileal brake, and delivers sustenance to your friendly flora. That’s what nature intended to happen.
That may be why apples are more satiating than apple juice—even when the juice is enriched with an identical amount of added fiber. Structure matters. You can’t just sprinkle on the fiber. Fiber is part of the matrix. The word matrix comes from the Latin matricis, derived from mater, meaning mother. We should strive to preserve the matrix (the blue pill, Neo) by choosing more unprocessed plant foods.
Even with identical chemistry, food structure may result in major differences in health outcomes. Corn chips and corn flakes cause a higher blood sugar spike than does corn on the cob. Even with identical ingredients, food structure can make a difference. For example, rolled oats have a significantly lower glycemic index than unsweetened instant oatmeal, which is also just straight oats but in thinner flakes, and oat flakes have a lower glycemic index than oat powder. The same single ingredient, oats, but in different forms can have different effects.
Why do we care? Because the overly rapid absorption of carbohydrates after eating a high-glycemic-index meal can trigger a sequence of hormonal and metabolic changes that promote excessive eating. In a study out of Harvard’s Children’s Hospital, a dozen obese teen boys were fed instant oatmeal versus steel-cut oatmeal. After the instant oatmeal, the teens went on to eat 53 % more than after eating the steel-cut oatmeal. The instant oatmeal group started snacking within an hour after their meal and went on to accumulate significantly more calories throughout the rest of the day.
Plain steel-cut oatmeal is considered a low-glycemic-index food, averaging under 55, whereas the instant oatmeal is a high-glycemic food, averaging over 70, but it isn’t as bad as some breakfast cereals, which can get even higher. This is even true of zero-sugar cereals like shredded wheat. The new industrial methods used to create breakfast cereals, such as extrusion cooking and explosion puffing, accelerate starch digestion and absorption, causing an exaggerated blood sugar response. Shredded wheat has the same ingredients as spaghetti—straight wheat—but a 70% higher glycemic index. This is one of the reasons why processing matters. Food structure may be critical for optimal health.
Eating whole grains is good, but eating whole-grain kernels is better. Former chair of Harvard’s Nutrition Department Walter Willett has argued that the term whole grain should probably be reserved for only whole intact grain kernels. So, eat the wholiest of grains, intact grains, also known as groats.
A breakfast meal including whole rye kernels, resulted in increased feelings of satiety in the afternoon, compared to porridge made of whole-grain rye flour. So, instead of buying boxed breakfast cereals, make oatmeal out of whole, intact oats. They’re gr-r-oat!
Please consider volunteering to help out on the site.
- Touvier M, da Costa Louzada ML, Mozaffarian D, Baker P, Juul F, Srour B. Ultra-processed foods and cardiometabolic health: public health policies to reduce consumption cannot wait. BMJ. 2023;383:e075294.
- Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3.
- Forde CG, Mars M, de Graaf K. Ultra-processing or oral processing? A role for energy density and eating rate in moderating energy intake from processed foods. Curr Dev Nutr. 2020;4(3):nzaa019.
- Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3.
- Almy TP. The dietary fiber hypothesis. Am J Clin Nutr. 1981;34(3):432-433.
- Burkitt DP, Walker AR, Painter NS. Effect of dietary fibre on stools and the transit-times, and its role in the causation of disease. Lancet. 1972;2(7792):1408-1412.
- Moloughney S. Dietary Fiber Market to Reach $3.25 Billion by 2017. Nutraceuticals World. Oct 29, 2012.
- Dietary Fibers Market to Expand at a CAGR 11.1% will Reach $21,672.9 Million billion by the End of 2030. EIN Presswire. Feb 26, 2024.
- McKeown NM, Fahey GC, Slavin J, van der Kamp JW. Fibre intake for optimal health: how can healthcare professionals support people to reach dietary recommendations? BMJ. 2022;378:e054370.
- Grundy MML, Carrière F, Mackie AR, Gray DA, Butterworth PJ, Ellis PR. The role of plant cell wall encapsulation and porosity in regulating lipolysis during the digestion of almond seeds. Food Funct. 2016;7(1):69-78.
- Flood-Obbagy JE, Rolls BJ. The effect of fruit in different forms on energy intake and satiety at a meal. Appetite. 2009;52(2):416-422.
- Fardet A. A shift toward a new holistic paradigm will help to preserve and better process grain products’ food structure for improving their health effects. Food Funct. 2015;6(2):363-382.
- Capozzi F, Magkos F, Fava F, et al. A multidisciplinary perspective of ultra-processed foods and associated food processing technologies: a view of the sustainable road ahead. Nutrients. 2021;13(11):3948.
- Brand JC, Nicholson PL, Thorburn AW, Truswell AS. Food processing and the glycemic index. Am J Clin Nutr. 1985;42(6):1192-1196.
- Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625-1632.
- Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625-1632. Supplementary Info.
- Mackie AR, Bajka BH, Rigby NM, et al. Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate. Am J Physiol Gastrointest Liver Physiol. 2017;313(3):G239-G246.
- Ludwig DS, Majzoub JA, Al-Zahrani A, Dallal GE, Blanco I, Roberts SB. High glycemic index foods, overeating, and obesity. Pediatrics. 1999;103(3):E26.
- Gearhardt AN, Bueno NB, DiFeliceantonio AG, Roberto CA, Jiménez-Murcia S, Fernandez-Aranda F. Social, clinical, and policy implications of ultra-processed food addiction. BMJ. 2023;383:e075354.
- Wahlqvist ML. Food structure is critical for optimal health. Food Funct. 2016;7(3):1245-1250.
- Willett WC. The dietary pyramid: does the foundation need repair? Am J Clin Nutr. 1998;68(2):218-219.
- Isaksson H, Rakha A, Andersson R, Fredriksson H, Olsson J, Aman P. Rye kernel breakfast increases satiety in the afternoon - an effect of food structure. Nutr J. 2011;10:31.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In the past few videos, I covered the nutrient profile of ultra-processed foods, the industrial contaminants, the additives––both intentional and unintentional––as well as changes in texture. But what’s this about food matrix?
In the famous study that found that ultra-processed diets caused excess calorie intake and weight gain compared to unprocessed diets––despite the fact that both diets were matched for calories, sugar, fat, and fiber, suggesting that it may be something about the processing itself, such as the concentration of calories and the changes in texture that allow for the foods to be eaten so much faster. But wait. How did the researchers match for fiber? It’s hard to imagine ultra-processed foods having much fiber.
Here are two representative dinners. On the ultra-processed side, nonfat yogurt, fruit in heavy syrup, baked potato chips, a deli meat and cheese sandwich, and three cups (720 ml) of diet lemonade. And with the same amount of calories, fat, and sugar on the unprocessed side, a Southwestern entrée salad with greens, beans, nuts, fruits, and vegetables. How could the ultra-processed meal possibly have the same amount of fiber? What they did was sprinkle a fiber supplement in the yogurt and lemonade. So technically, both meals had the same amount of fiber. But that’s not how fiber works.
A half century ago, the dietary fiber hypothesis was proposed, suggesting that fiber was the reason that diets centered around whole plant foods were so protective against chronic disease. Predictably, this gave rise to a multibillion-dollar fiber supplement market. People could just eat real food, but where’s the money in that? (Of course, it’s hard to trust projections from internet press releases. I highly doubt the fiber market is going to hit 20,000 million billion.)
Those who get more fiber in their diet are significantly less likely to get heart disease, strokes, and diabetes, and less likely to die from cancer and all causes put together, but that’s with fiber from food. In terms of fiber intake for optimal health, the first line of defense for disease prevention is to focus on fiber from foods rather than supplements. For the treatment of disease, there is a lack of evidence-based research to support the use of most isolated fiber types. You can’t just take your magic bullet of Metamucil with your Wonder Bread. That’s not how fiber works.
Dietary fiber alone has certain benefits, but its primary role may be the physical encapsulation of nutrients inside the cell wall for special delivery to our gut microbiome. Fiber makes up the cell walls of plants, which act as an indigestible physical barrier. So, when we eat structurally intact plant foods, many of the nutrients remain trapped. Chew all you want—you’re still going to end up with nutrients completely surrounded by fiber, which then blunts the glycemic response, activates a natural satiety mechanism called the ileal brake, and delivers sustenance to your friendly flora. That’s what nature intended to happen.
That may be why apples are more satiating than apple juice—even when the juice is enriched with an identical amount of added fiber. Structure matters. You can’t just sprinkle on the fiber. Fiber is part of the matrix. The word matrix comes from the Latin matricis, derived from mater, meaning mother. We should strive to preserve the matrix (the blue pill, Neo) by choosing more unprocessed plant foods.
Even with identical chemistry, food structure may result in major differences in health outcomes. Corn chips and corn flakes cause a higher blood sugar spike than does corn on the cob. Even with identical ingredients, food structure can make a difference. For example, rolled oats have a significantly lower glycemic index than unsweetened instant oatmeal, which is also just straight oats but in thinner flakes, and oat flakes have a lower glycemic index than oat powder. The same single ingredient, oats, but in different forms can have different effects.
Why do we care? Because the overly rapid absorption of carbohydrates after eating a high-glycemic-index meal can trigger a sequence of hormonal and metabolic changes that promote excessive eating. In a study out of Harvard’s Children’s Hospital, a dozen obese teen boys were fed instant oatmeal versus steel-cut oatmeal. After the instant oatmeal, the teens went on to eat 53 % more than after eating the steel-cut oatmeal. The instant oatmeal group started snacking within an hour after their meal and went on to accumulate significantly more calories throughout the rest of the day.
Plain steel-cut oatmeal is considered a low-glycemic-index food, averaging under 55, whereas the instant oatmeal is a high-glycemic food, averaging over 70, but it isn’t as bad as some breakfast cereals, which can get even higher. This is even true of zero-sugar cereals like shredded wheat. The new industrial methods used to create breakfast cereals, such as extrusion cooking and explosion puffing, accelerate starch digestion and absorption, causing an exaggerated blood sugar response. Shredded wheat has the same ingredients as spaghetti—straight wheat—but a 70% higher glycemic index. This is one of the reasons why processing matters. Food structure may be critical for optimal health.
Eating whole grains is good, but eating whole-grain kernels is better. Former chair of Harvard’s Nutrition Department Walter Willett has argued that the term whole grain should probably be reserved for only whole intact grain kernels. So, eat the wholiest of grains, intact grains, also known as groats.
A breakfast meal including whole rye kernels, resulted in increased feelings of satiety in the afternoon, compared to porridge made of whole-grain rye flour. So, instead of buying boxed breakfast cereals, make oatmeal out of whole, intact oats. They’re gr-r-oat!
Please consider volunteering to help out on the site.
- Touvier M, da Costa Louzada ML, Mozaffarian D, Baker P, Juul F, Srour B. Ultra-processed foods and cardiometabolic health: public health policies to reduce consumption cannot wait. BMJ. 2023;383:e075294.
- Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3.
- Forde CG, Mars M, de Graaf K. Ultra-processing or oral processing? A role for energy density and eating rate in moderating energy intake from processed foods. Curr Dev Nutr. 2020;4(3):nzaa019.
- Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3.
- Almy TP. The dietary fiber hypothesis. Am J Clin Nutr. 1981;34(3):432-433.
- Burkitt DP, Walker AR, Painter NS. Effect of dietary fibre on stools and the transit-times, and its role in the causation of disease. Lancet. 1972;2(7792):1408-1412.
- Moloughney S. Dietary Fiber Market to Reach $3.25 Billion by 2017. Nutraceuticals World. Oct 29, 2012.
- Dietary Fibers Market to Expand at a CAGR 11.1% will Reach $21,672.9 Million billion by the End of 2030. EIN Presswire. Feb 26, 2024.
- McKeown NM, Fahey GC, Slavin J, van der Kamp JW. Fibre intake for optimal health: how can healthcare professionals support people to reach dietary recommendations? BMJ. 2022;378:e054370.
- Grundy MML, Carrière F, Mackie AR, Gray DA, Butterworth PJ, Ellis PR. The role of plant cell wall encapsulation and porosity in regulating lipolysis during the digestion of almond seeds. Food Funct. 2016;7(1):69-78.
- Flood-Obbagy JE, Rolls BJ. The effect of fruit in different forms on energy intake and satiety at a meal. Appetite. 2009;52(2):416-422.
- Fardet A. A shift toward a new holistic paradigm will help to preserve and better process grain products’ food structure for improving their health effects. Food Funct. 2015;6(2):363-382.
- Capozzi F, Magkos F, Fava F, et al. A multidisciplinary perspective of ultra-processed foods and associated food processing technologies: a view of the sustainable road ahead. Nutrients. 2021;13(11):3948.
- Brand JC, Nicholson PL, Thorburn AW, Truswell AS. Food processing and the glycemic index. Am J Clin Nutr. 1985;42(6):1192-1196.
- Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625-1632.
- Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr. 2021;114(5):1625-1632. Supplementary Info.
- Mackie AR, Bajka BH, Rigby NM, et al. Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate. Am J Physiol Gastrointest Liver Physiol. 2017;313(3):G239-G246.
- Ludwig DS, Majzoub JA, Al-Zahrani A, Dallal GE, Blanco I, Roberts SB. High glycemic index foods, overeating, and obesity. Pediatrics. 1999;103(3):E26.
- Gearhardt AN, Bueno NB, DiFeliceantonio AG, Roberto CA, Jiménez-Murcia S, Fernandez-Aranda F. Social, clinical, and policy implications of ultra-processed food addiction. BMJ. 2023;383:e075354.
- Wahlqvist ML. Food structure is critical for optimal health. Food Funct. 2016;7(3):1245-1250.
- Willett WC. The dietary pyramid: does the foundation need repair? Am J Clin Nutr. 1998;68(2):218-219.
- Isaksson H, Rakha A, Andersson R, Fredriksson H, Olsson J, Aman P. Rye kernel breakfast increases satiety in the afternoon - an effect of food structure. Nutr J. 2011;10:31.
Motion graphics by Avo Media
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Title
How Ultra-Processed Foods Could Cause Disease: Changes in Structure
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Content URLDoctor's Note
If you missed the previous videos in this series, check out:
- What Are Ultra-Processed Foods?
- How Bad Are Ultra-Processed Foods?
- Which Ultra-Processed Foods Are the Worst in Driving the Association with Death and Disease?
- Do the Health Impacts of Ultra-Processed Foods Apply to Plant-Based Meat Alternatives?
- How Ultra-Processed Foods Could Cause Disease: Food Additives
- How Ultra-Processed Foods Could Cause Disease: Industrial Contaminants
- How Ultra-Processed Foods Could Cause Disease: Packaging Chemicals
- How Ultra-Processed Foods Could Cause Disease: Loss of Phytonutrients
- How Ultra-Processed Foods Could Cause Disease: Changes in Texture
- How Ultra-Processed Foods Could Cause Disease: Calorie Density
Stay tuned for the rest of this extended video series on ultra-processed foods, coming out over the next several months.
If you don’t want to wait for each video to be released, we’ve compiled all the information into a new book, Ultra-Processed Foods: Concerns, Controversies, and Exceptions.
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