Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Spaghetti hoops on toast, sausages and bacon are served in a canteen

White toast topped with spaghetti hoops is the epitome of ultra-processed food. Such foods have been linked with weight gain. Credit: Paula Solloway/Alamy

Nutrition

First strict test shows why a junk-food diet packs on weight

A steady repast of pancakes, packaged snacks and processed meats prompted people to consume more calories.

Harried humans around the world are embracing cheap, ultra-processed foods such as white bread, bacon and hash browns. But the first randomized controlled trial on the health effects of these foods shows that people offered such a diet ingest more calories — and pack on more weight — than they do when presented with more wholesome meals.

To determine how processed foods affect health, Kevin Hall at the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland, and his colleagues fed study participants ultra-processed foods for two weeks. The same participants also spent two weeks eating unprocessed foods, such as fish and fresh vegetables. Both types of meal had the same number of calories, and the same levels of nutrients such as sugar and fat. Participants chose how much to eat.

When offered ultra-processed foods, people ate more quickly and took in an average of 500 more calories per day than when they were offered unprocessed foods. Participants gained roughly 1 kilogram during the trial’s junk-food phase and lost roughly the same amount during the whole-foods phase.

More Research Highlights...

Ember and thick smoke from bushfires reach Braemar Bay in New South Wales

Vast bush fires that swept across Australia at the end of 2019 and the start of 2020 filled the skies with enough smoke to warm a portion of the atmosphere. Credit: Saeed Khan/AFP/Getty

Atmospheric science

Smoke from Australian fires turned up the heat in the southern sky

The catastrophic wildfires of late 2019 and early 2020 triggered a lingering temperature rise in a section of Earth’s lower atmosphere.
Visible and infrared images of the device in fully discharged and charged states

A display screen in its uncharged (top left) and charged (top right) state in visible light. The screen reflects one range of infrared wavelengths when uncharged (bottom left) and another range when charged (bottom right). Credit: M. S. Ergoktas et al./Nature Photon.

Optics and photonics

One screen, three images — some invisible in ordinary light

A graphene-based device can display several images simultaneously using a range of wavelengths.
Woman harvesting teff, Ethiopia

A farmer in Ethiopia harvests teff, a cereal. Small farms tend to have more-diverse landscapes than do sprawling industrial operations. Credit: Andia/Universal Images Group/Getty

Environmental sciences

Small farms outdo big ones on biodiversity — and crop yields

Large-scale farms account for most of the global food supply, but smallholdings protect species and are just as profitable.
Diagram of the nuclear composition and electron configuration of an atom of xenon-132.

A xenon atom’s electrons (grey circles; illustration) have been observed and even manipulated as they shifted their position. Credit: Carlos Clarivan/Science Photo Library

Atomic and molecular physics

An atom shuffles its electrons at ultrahigh speed — and is caught in the act

Scientists capture the movement of electrons in a xenon atom, a phenomenon that lasts for a fraction of one-billionth of a second.
Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing

Search

Quick links