How ultra-processed foods affect the gut microbiome and health

While the occasional fast-food meal or pack of biscuits won’t harm you, making ultra-processed foods too much of your diet might. Sounds dramatic? That’s because it is.

There is every reason to be concerned about the harmful effects of ultra-processed foods on our gut microbiome – and therefore overall health.

Today, ultra-processed foods make up more than half of the diet of the population in many countries (3), with high-sugar breakfast cereals, microwave meals, and pizzas filling up freezers and cupboards nation-wide.

Combine this with research showing links between ultra-processed foods and increased risk of lifestyle-related diseases and early death (2), there is reason to be concerned.

What are ultra-processed foods?

Looking at what ultra-processed food really means, the British Medical Journal uses the following definition:

“Ultra-processed foods are industrial formulations made by deconstructing whole foods into chemical constituents, altering them and recombining them with additives into products that are alternatives to fresh and minimally processed foods and freshly prepared meals” (1).

The British Medical Journal, 2022

Well, that’s the thing. We know that ultra-processed foods are designed to be cheap, tasty, durable, convenient, and appealing. They can be extremely hard to resist and even border-line addictive!

When temptation strikes, remember these facts about ultra-processed foods. They:

  • Are more calorie dense, and we consume them 50% faster!
  • Can damage your gut lining – causing inflammation. PS inflammation is linked to health issues such as diabetes 2 and heart disease. 
  • Reduce gut microbe diversity – a key indicator of good health.

Does this mean we need to get up an hour early every day to make even the granola from scratch?

No. Because I rarely believe in extremes, I would never say never even to ultra-processed foods.

When life gets in the way, any “make every meal from scratch”-plan can meet resistance. So do enjoy that occasional fast food meal and colorful sweets – just be aware of the science behind it, and enjoy in moderation.


Every effort is a win

Because the good news is that every effort counts. And knowing the science behind it, at least helps me fight off a craving or two as I pass by the all-too available snacks and pre-packaged dinners in the grocery store.

And every time we make the effort to choose unprocessed or minimally processed over ultra-processed food, it’s a win.

Because like the British Medical Journal (4) says:

  • Higher consumption of ultra-processed foods (more than 4 servings per day) is associated with a 62% increased risk of all-cause mortality compared with lower consumption (less than 2 servings per day)
  • For each additional daily serving of ultra-processed food, mortality risk relatively increased by 18% (a dose-response effect)

3 tips for a healthy gut microbiome

In short, here are three guidelines for ultra-processed foods and gut health:

  • Avoid ultra-processed foods when possible
  • Choose fresh foods and / or foods with “real” ingredients when you shop
  • Make meals from scratch when you can

So, while I agree whole-heartedly with the researchers quoted in the British Medical Journal study that “policies to limit ultra-processed food intake are urgently needed”, I’m happy to know that every effort to eat healthy counts!

NOTE: This does not constitute medical advice. Seek advice from a healthcare professional as needed


The trouble with ultra-processed foods | The BMJ
Barns konsum av ultraprosessert mat og fedmeutvikling –
To nye studier kobler ultra­prosessert mat til helseproblemer (
New evidence links ultra-processed foods with a range of health risks | BMJ

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