Wholefood diet lets you eat 57 per cent more food while cutting hundreds of calories, scientists say

Yet despite eating significantly larger quantities, the wholefood group still took in 330 fewer calories each day on average.

The study, co-authored by leading US nutrition experts, reanalysed data from a landmark clinical trial led by Dr Kevin Hall at the US National Institutes of Health.

The scientists believe these findings point to something they are calling "nutritional intelligence", where the body knows what it needs when given natural options.

Participants on the wholefood diet consistently loaded up on fruit and vegetables, sometimes eating several hundred grams per meal, rather than reaching for higher-calorie options like steak, pasta and cream.

As Professor Jeff Brunstrom, who led the study, put it: "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."

The team calls this phenomenon "micronutrient deleveraging" – we naturally favour vitamin-rich produce over energy-dense alternatives.

The ultra-processed foods painted a very different picture.

Contrary to what many assume about "empty calories," these products actually delivered essential vitamins and minerals – but through artificial fortification rather than natural sources.

When focusing on Vitamin A in the ultra-processed diet, for example, the richest sources were calorie-laden French toast sticks and pancakes. Those eating wholefoods got theirs from carrots and spinach instead.

Dr Annika Flynn, a co-author on the study, warned: "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."

Professor Brunstrom reckons the real issue is not simply eating too much.

"Overeating is not necessarily the core problem," he explained. "Indeed, our research clearly demonstrated consumers on a wholefood diet actually ate far more than those on a processed food one."

The key, he says, lies in how food composition shapes our choices.

"It seems that UPFs 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."

So for anyone who made a New Year's resolution to eat cleaner, the science suggests your body might just thank you for it.