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How Do Processed Foods Affect Health?

Sharon Palmer

I’m answering your top questions on how eating highly processed foods affects health today. We know we should fill our plates with mostly whole plant foods, so rich in nutrients, fiber, and health-promoting plant compounds. We also know we should significantly minimize highly processed “junk” foods—refined foods, such as sugar beverages, white breads, and deep-fried snacks—which don’t compare nutritionally. These foods are linked to issues like inflammation, poor gut health, and chronic diseases, like cancer, heart disease, and diabetes. It can be especially challenging to avoid them when the Western diet is teeming with highly processed foods that contain things like added sugars, refined grains, and processed meat. Not to worry! Cutting back is very doable, and you can still enjoy the occasional treat, just make sure it’s in addition to a meal with plenty of delicious whole plant foods. Check out my nutrition advice on how to understand processed foods and health in your healthy lifestyle.

How Do Processed Foods Affect Health?

Question: It’s been reported that highly processed foods are linked with chronic inflammation and oxidative stress, as well as poor gut microbiome profiles. How exactly do those things relate back to poor digestion and poor gut health?

Sharon’s Answer: The three hallmarks of a healthy microbiome are: 1) diversity of gut microbes—meaning a larger variety of different types 2) a profile of “good” microbes that are linked with health, rather than the “bad” microbes that are linked with negative health outcomes, and 3) a higher volume of these microbes in the gut. When you eat a diet filled with healthy, high-fiber foods, like beans, whole grains, and veggies, you feed those bacteria with fiber, which they need to survive. Americans eat so few of these foods, it’s no wonder so many of us have poor gut microbiomes. One of the key ways that gut microbiota work to protect health is by fermenting fiber in the gut to create short chain fatty acids, which have been linked to health benefits, such as lower risk of inflammatory diseases, diabetes, and cardiovascular disease. They have also been recognized as mediators in intestinal immune function, and have a role to play in regulating the inflammatory process and destroying pathogens. 

Mississippi Caviar is a high-fiber, whole food recipe gut for your gut.

Question: How would it feel to have low diversity in your gut microbiome? What digestive system issues, chronic inflammation, and oxidative stress could result from that?

Sharon’s Answer: There is not a lot of data on how you might “feel” based on various microbiota profiles. We do know that dysbiosis is linked to conditions like inflammatory bowel disease. Healthy gut microbiome is linked with gut defense system and normal gut function. The gut bacteria also help digest foods, produce vitamins, help absorb nutrients, destroy toxins, and many other functions. These are all activities that lead to good health and wellbeing, but they are kind of vague in the sense of “feeling” something at that moment in time. Gut bacteria has also been linked to the reduced risks of conditions like colon cancer, heart disease, diabetes, and liver disease. There is even research that suggests people who have constipation and people who have rheumatoid arthritis have lower counts of friendly bacteria.

Question: You also have said that consuming highly processed foods, as opposed to high fiber foods, increases risk of colon cancer. Is this simply because they lack fiber, or is it something in the processed foods themselves that can spur colon cancer?

Sharon’s Answer: The Western diet is strongly linked to colon cancer. It is high in red meat, added sugars and refined grains, and low in the foods I mentioned above. There are many reasons that the diet is linked with increased risk, including low in fiber and antioxidant compounds, but also that the presence of red and processed meat is probably carcinogenic, per the World Health Organization (WHO). Refined carbohydrates rapidly alter blood glucose and insulin levels, which can increase oxidative stress and inflammation. Saturated fat also increases inflammation by way of increased absorptions of endotoxins in the gut into the bloodstream. 

Jicama Grapefruit Salad is rich in whole plant foods for optimal health.

Question: How should we approach our relationship to processed food? What’s a doable, actionable way to help people cut back?

Sharon’s Answer: Try to increase your intake of whole plant foods as much as possible. You don’t have to be a purist, you can have one small treat a day, but make sure the majority of your diet is filled with whole plant foods. Research found that eating a good source of particularly potent healthy whole foods like strawberries and tomatoes at a typical Western diet meal helped undo the bad effects of inflammation at that meal. So, keep that in mind. If you’re going to indulge, make sure that you have a super healthy meal too—don’t pile further insults on top of an unhealthful meal. Instead of having a whole meal that is mired in saturated fat, refined carbs, and no whole plants and adding an ice cream sundae to that, have a plant-based meal filled with whole plant foods, and then have your treat with that meal.

Check out other nutrition questions I’m answering at The Plant-Powered Dietitian:

Does Roasting Veggies Ruin Nutrients?
Is “Clean Eating” a Healthy Lifestyle?
How to Prepare Dried Beans to Avoid Antinutrients

About Ask Sharon:

As part of my program “Ask Sharon”, I am answering the top question of the month submitted through my blogFacebookTwitter or Instagram to answer here. You can even win a prize! Don’t forget to submit your burning nutrition question via my blog, or other social media.

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