Study shows heavily processed foods encourage you to overeat

Here’s good news if your 2020 Food Resolutions are starting to go belly-up: a landmark scientific study suggests that the industrial processing of food makes us want to eat more of it. Processed foods are habit-forming. And you thought it was your lack of willpower! Not entirely.

The clinical study was organized at the National Institutes of Health in Bethesda, Maryland. There were two groups of volunteers: one group ate a diet of highly-processed foods for two weeks and the other ate a low-processed, whole foods diet for the same period. After two weeks, the groups switched places.

Volunteers in the highly-processed food group overate and gained weight during the two week observation period compared to the volunteers presented with a diet of unprocessed foods – even when the 2 diets had the same available calories and nutrients!

The difference between processed and unprocessed food:

So you might ask: How did this study define processed food versus unprocessed food? Isn’t all the food we buy somewhat processed anyway?

This study defined processed foods as containing lots of added fat, sugar and salt. And ultra-processed foods are often in ready to eat formulas containing flavor-enhancing additives, dyes or stabilizers (which prevent ingredients from separating and also give them a longer shelf-life). 

Examples of processed food are packaged breakfast cereals, canned ravioli (I grew up on that!), sweetened yogurt and hot dogs.

Minimally processed foods included in this study were frozen, dried, cooked or vacuum packed, but without added sugar, salt or oils.
Examples of unprocessed foods for this study were: oatmeal, steamed vegetables, salads, and grilled chicken.

Participants chose how much they ate:

The study’s participants couldn’t choose what they ate, but they could choose how much they ate. Everything was calculated to gauge the quantity of food they’d consumed. 

After 2 weeks, researchers found that those on the processed food diet were eating on average 500 calories more per day than the participants in the unprocessed food group.

The 500 extra calories each day led to a gain of 2.2 pounds (or 1 kilogram) versus a loss of the same amount of weight for participants following the unprocessed diet.

Researchers suspect that people overate on the processed food diet because the additives make the food more appealing. Also, as processed food is softer and easier to chew, it’s easier to eat a lot of it – especially when eating quickly. 

It’s not only what you eat, but how you eat it that counts:

Here’s another important observation made in this study: participants on the processed food diet ate faster than those on the whole food diet.  When you eat faster you tend to consume more calories.

Though the nutritional profiles of the foods in the 2 different groups were almost perfectly matched (they had about the same amount of proteins, carbs, and fats), the processed food did contain slightly less protein. 

We tend to consume the same amount of protein and weight of food every day 

Some researchers find that people tend to eat until they reach their “protein target.” So if protein content in a meal is lower, as it is in processed foods, studies suggest that people will eat more until they reach their usual, daily protein amount.

Also, ultra-processed foods tend to be higher in calories and lower in fiber for the same weight compared to low processed foods. Though the study tried to balance this by adding fiber-containing drinks to the ultra-processed group’s diet, participants tended to eat a consistent weight or volume of food from day to day. 

As the ultra-processed food has more calories for the same weight, the participants in that group consumed more calories on the processed food diet.

Does the processing of food sabotage your diet?

Some observers of this study aren’t convinced that the high processing of food by industrial manufacturers is a threat to health. 

Though obesity and its related illnesses are more common among those eating highly processed foods, a direct causal link hasn’t been found yet.

Realistically, our modern lifestyles need some processing of food – otherwise, we wouldn’t be able to feed everyone. Also, not everyone has the time or the means to prepare a farm to table meal every night after a long day at work!

Conclusion: Yet another warning shot:

In my opinion, this study is a warning shot that illustrates how processed foods are better off having a minor role in anyone’s diet. Even so, trends show that consumers are giving them a more dominant role in everyday meals to save time and money.

The savings in meal prep time and in money they seem to provide aren’t worth the health problems they cause down the line. 

A better strategy would be to keep meals quick and simple by using minimally processed foods and relying on great pantry ingredients to do the work of adding deliciousness: a top olive oil and vinegar on a raw vegetable or a terrific spice mix on plain grilled meat will go a long way to adding healthy flavor without additives and colorings.

Read more about what products you can add to your pantry for simple, healthy meals with extra deliciousness here.

And now you: What do you think about this landmark study?

Do you rely on processed food for quick meals? Leave a comment below and let me know!

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Photos courtesy of Unsplash.com