• Posted January 20, 2026

Whole Foods Diet Allows Folks To Eat More While Cutting Calories, Analysis Shows

Did you make a New Year’s resolution to ditch ultra-processed foods and eat only whole foods?

If so, you have better odds of losing weight in 2026 even as you chow down, a new study says.

People following a completely unprocessed, whole foods diet tend to eat a lot — a whopping 57% greater amount than those who only eat ultra-processed foods, researchers found.

Despite that, they still consume, on average, 330 fewer calories from food every day, researchers reported in The American Journal of Clinical Nutrition.

It turns out that people on a whole foods diet naturally lean toward eating a lot more fruit and veggies, rather than higher-calorie whole food options like rice, meat and butter, researchers found.

“Overeating is not necessarily the core problem. Indeed, our research clearly demonstrated consumers on a whole food diet actually ate far more than those on a processed food one,” said lead researcher Jeff Brunstrom, a professor of experimental psychology at the University of Bristol in the U.K.

“But the nutritional make-up of food is influencing choices and it seems that ultra-processed foods are nudging people towards higher calorie options, which even in much lower quantities are likely to result in excess energy intake and in turn fuel obesity,” Brunstrom said in a news release.

For the new study, researchers re-analyzed data gathered during a landmark 2019 clinical trial testing the effects of an ultra-processed foods diet versus a whole foods diet. Participants were randomly assigned to try one diet for two weeks, then the other.

Though meals were matched for calories, folks nevertheless ate an average of 508 calories a day more on the ultra-processed diet, the original study found. 

People gained about two pounds during the week they ate ultra-processed foods, and lost two pounds on the whole foods diet.

In this follow-up analysis, researchers took a closer look at exactly what people were munching when offered a whole foods diet.

All participants eating only whole foods chose to load up on fruits and veggies, sometimes consuming several hundred grams per meal, researchers found. They chose those over more calorie-dense options like steak, pasta and cream.

Overall, this resulted in those on the whole foods diet eating 57% more, based on food weight.

However, their calorie count wound up lower than when they ate only ultra-processed foods, the study found.

These results suggest that people might have an inbuilt “nutritional intelligence” that helps guide our food choices, researchers said.

“It’s exciting to see when people are offered unprocessed options they intuitively select foods that balance enjoyment, nutrition and a sense of fullness, while still reducing overall energy intake,” Brunstrom said.

“Our dietary choices aren’t random – in fact we seem to make much smarter decisions than previously assumed, when foods are presented in their natural state,” Brunstrom said.

The range and volume of fruits and veggies consumed by the participants contained essential vitamins and minerals that they wouldn’t have gotten if they’d chosen higher-calorie whole food options, researchers found.

“Had participants eaten only the calorie-rich foods, our findings showed they would have fallen short on several essential vitamins and minerals and eventually developed micronutrient insufficiencies,” said researcher Mark Schatzker, a food journalist in residence at McGill University in Canada. “Those micronutrient gaps were filled by lower calorie fruits and vegetables.”

This same nutritional intelligence also appeared at work when people chose between ultra-processed foods, to disturbing effect.

People chose options that met their micronutrient requirements, often through vitamin fortification. Unfortunately, those foods also were loaded with calories.

For example, ultra-processed foods richest in vitamin A were calorie-dense French toast sticks and pancakes. Among whole foods, most people got their vitamin A from low-calorie carrots and spinach.

“This raises the alarming possibility that UPFs deliver both high energy and micronutrients in one hit, which could result in calorie overload, because they effectively kill the beneficial trade-off between calories and micronutrients,” said study co-author Annika Flynn, a senior research associate at the University of Bristol.

“Conversely, this healthy competition is promoted by whole foods and therefore encourages people eating them to favor micronutrient powerhouses, such as fruit and veggies, over high-energy options like pasta and meat,” Flynn said.

More information

The American Heart Association has more on ultra-processed foods.

SOURCE: University of Bristol, news release, Jan. 19, 2026