Research reveals that processed foods cause overeating and slow fat loss

You don’t have to delve too far into the research on processed foods to find out that they slow down our fitness journeys. That’s because the combination of added ingredients like salt, fat and a long list of preservatives wreak havoc on gut health and have even been linked to osteoarthritis. Now a new study from the University of Bristol has shed light on how many extra calories you’ll consume when you opt for convenience, and why whole foods are a clear winner when it comes to losing weight while eating more.

The study, published in The American Journal of Clinical Nutritionwas the result of valuable teamwork from the University of Bristol in the UK and nutritionists in the US, who discovered that when we eat a lot of fast or processed foods, our body’s ability to make healthy choices decreases. It seems we all have an innate “nutritional intelligence” that serves us well when we eat whole foods, but it goes haywire when we opt for processed diets, binge on empty calories, and derail our fitness goals.

How was the research conducted?

Individuals with consistently stable body weight were told to follow separate, two-week diets with both ultra-processed and unprocessed meals to assess how these regimens would regulate their overall food choices, meal sizes, and nutrient intake.

How ultra-processed foods disrupt your body’s natural hunger signals

The experts found that people eating a completely unprocessed diet consumed more than 50% more food than those eating only UPFs, but incredibly, the unprocessed group ate an average of 330 fewer calories per day. “It’s exciting to see when people are presented with unprocessed options, they intuitively select foods that balance pleasure, nutrition and a feeling of satiety, while still reducing overall energy intake,” said the study’s lead author, Jeff Brunstrom. The results showed that instead of turning to higher calorie foods like rice or butter, the unprocessed group opted for options like fruits and vegetables, without a concerted effort to cut calories.

“Our food choices are not random – in fact, we appear to make much smarter decisions than previously thought when food is presented in its natural state,” Brunstrom added. Building on previous work that had found a similar pattern, the team believes they have also discovered why people who ate only whole foods tended to eat healthier overall. The new study concludes that the entire food group could make choices that allowed them to reap the benefits of essential vitamins and nutrients because this behavior reflects a form of nutritional intelligence that scientists call “micronutrient deleveraging,” while the UPF group ate more calories but developed a more negative nutritional profile. This intelligence is compromised when eating a processed diet, and people tend to pursue energy-dense foods.

“Overeating is not necessarily the core problem,” Brunstrom explains. “But the nutritional value of food influences choices, and it appears that UPFs push people toward higher calorie options, which even in much lower amounts are likely to result in excess energy intake and in turn fuel obesity.”

If you’ve ever eaten a ton of junk calories from processed foods and felt hungry a short time later, this theory may ring true for you. Instead, it’s heartwarming (and heart healthy) to learn that focusing on whole foods means a fuller stomach, with fewer calories consumed and better nutrition for our bodies.