There are so many different diets out there, all of them claiming to be the single best solution. This lead to significant public confusion about nutrition because some of the diets suggest principles that are contrary to each other. What do you have to follow? What to believe? But there is one thing all successful diets implement directly or indirectly and that is avoiding ultra-processed food. And now we have scientific support for this principle!
What are ultra-processed foods?
First we have to look how to define ultra-processed foods. In the study I will discuss later, researchers chose to use the NOVA score:
The NOVA (a name, not an acronym) classification, developed by researchers at the University of Sāo Paulo in Brazil, assigns foodstuffs to four groups according to the extent and purpose of industrial food processing.
Class one are unprocessed foods like meat, vegetables and fruits. Class four constitutes the highly processed “junk food” everybody knows is bad, but most of us still eat: sweetened sodas, instant noodles and other convenience food.
Most class four foods also include flavour enhancers, artificial flavours, emulsifiers and preservatives. In my strict paleo-days I would have told you that’s all poison. As I broadened my horizon, I came more and more to the conclusion that most of those additives are harmless, as long as you don’t overconsume them and have a balanced, healthy diet to make up for them.
Still, flavour enhancers and artificial flavours have the problem that they make foods ultra-palatable, tastier than nature would have made them, and can therefore induce overeating.
Why are ultra-processed foods “bad”?
Overeating can be real problem in any ad libitum setting like the life of most people is: they eat what they want and how much they want. For many of us this is already a difficult combination: in my experience if I don’t track macros, go by feel and additonaly do not limit my food choices, I can easily gain half a kilo per week! My food choices come mostly from the class one list and my “cheats” are more like lamb shoulder, roast duck, sweet potatoes, homemade sourdough bread and some high quality chocolate, far far away from ice cream, white bread, french fries and hamburgers.
The first problem of ultra-processed foods is the use of everything the food industry has in its arsenal to make food as palatable (tasty) as possible. “Hyperpalatability” is the word often used in this context. This includes liberal use of flavour enhancers, artificial flavour, salt, sugar and fat. And they also manipulate consistencies to make food as appealing and exciting as possible. A combination our brain didn’t evolve to handle.
The second problem is maybe even more severe: high energy density. Ultra-processed foods generally have lots of calories per 100g of weight. Just compare boiled potatoes with french fries! One of the most important signals for our brain to stop eating is how full your stomach is. Therefore it takes many calories to fill out our stomach if you use ultra-processed foods. Overeating is very likely to happen! Our body is surprisingly bad at estimating the calories we are eating. If it would be better, there wouldn’t be such an obesity pandemic like we have right now.
What science says
And now we finally have a well made study to back all this up. Take a look into it, it is well written and surprisingly easy to understand.
The researchers took twenty weight stable female and male subjects and randomized them into a ultra-processed and unprocessed diet group. They dieted accordingly for two weeks and then switched to the other diet for another two weeks. During the entire period of the study subjects were admitted to the clinical center where they were provided with all meals, drinks and snacks. Cheating was impossible.
Meals were designed to be matched for presented calories, energy density, macronutrients, sugar, sodium, and fiber. Subjects were instructed to consume as much or as little as desired. If you want to know what they exactly ate, take a look into the study appendix, where you can find every single meal provided. It’s also very interesting to see how the same macros look like if you use unprocessed or ultra-processed foods.
And it turned out to be exactly as expected: everyone in the ultra-processed group ate about 500kcal more than the unprocessed group. Weight changed accordingly: participants in the ultra-processed group gained about 0,8kg and lost about 1,1kg during the unprocessed diet phase.
This were only a few weeks. Think about what this will mean for someone who spends his entire life on the ultra-processed diet, a.k.a. the “western diet”! Unsurprisingly the scientists conclude:
Limiting consumption of ultra-processed foods may be an effective strategy for obesity prevention and treatment.
If you don’t want to count your macros to loose fat, consider following a diet that exclusively uses unprocessed foods. Primal, Paleo or Clean Eating come to mind here. All of them have their advantages and disadvantages, but they are a good place to start. They force you into a new way of thinking about food. You have to shop differently, you have to cook, you have to plan. All this slowly takes you to a better relationship with food. You learn to value a beautiful cut of meat. You fall in love with seasonal fruits and vegetables. And finally you question how you were able to survive and like all this ultra-processed crap.
But also see the limitations. If you are like me and have the metabolism of a sloth, you can easily gain weight on completely “clean” foods. If this is the case, you have to eliminate or restrict certain foods from your diet, even if they are really healthy and unprocessed just to lower the calorie content of your diet. Or you make the big leap and start tracking. That’s up to you.
If you need help to set up your diet, feel also free to contact me (free of charge). Let us talk on how to work together on a healthy, sustainable lifestyle which meets your goals.
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