The $190 Million Question: What Are We Supposed to Eat?

A new study could cut through years of confusion about nutrition guidance

By Andrea Petersen | Photographs by Christiana Botic for The Wall Street Journal
Feb. 20, 2024
Tap story

Kevin Elizabeth is one of 500 Americans who will be living at scientific facilities around the country for six weeks, eating precisely selected meals and undergoing hundreds of medical tests.

Elizabeth at Pennington Biomedical Research Center in Baton Rouge, La.

The 28-year-old tech worker is part of a new study, costing $189 million, that is one of the most ambitious nutrition research projects the National Institutes of Health has ever undertaken.

If the study succeeds, it could help Americans get healthier and cut through years of confusion about nutrition guidance.

At the kitchen preparing study participants' meals, food is measured to the tenth of the gram.

Chronic diseases linked to our diets are on the rise. Sometimes-conflicting advice hasn’t helped—remember the low-fat craze?—and has resulted in little improvement in our health.

A research specialist measures chicken salad.

41.9%

The percentage of U.S. adults ages 20 and over with obesity, according to Centers for Disease Control and Prevention data collected from 2017 to 2020. That is up from 30.5% in 1999 to 2000.

Individual servings of Lifesaver Gummies are packaged for study participants.

The study will involve 10,000 participants in all. Some are signing up for intense measures, like monitors that follow them and make sure they don’t eat smuggled food, or special eyeglass cameras to record what they eat.

During a recent test to measure Elizabeth's resting metabolic rate, a TV was on. “They can’t watch the Food Network,” said biomedical engineer Isabella Reed, who said even looking at food can change the test results. “We watch a lot of Hallmark movies and HGTV."

And then there’s the bathroom. Some participants elsewhere in the NIH study are using a new “smart” toilet paper device to collect stool samples.

If all goes according to plan, in a few years you’ll be able to walk into your doctor’s office, get a few simple medical tests, answer questions about your health and lifestyle, and receive personalized diet advice, says Holly Nicastro, coordinator for the NIH’s Nutrition for Precision Health study.

Researchers are measuring people's insulin and glucose levels, among many other metrics.

Scientists agree broadly on what constitutes a healthy diet—heavy on veggies, fruit, whole grains and lean protein—but more research is showing that different people respond differently to the same foods, such as bread or bananas.

Elizabeth and his fellow participants spend two weeks each on three different diets.

One is high fat and low carb; another is low on added sugars and heavy on vegetables, along with fruit, fish, poultry, eggs and dairy; a third is high in ultra-processed foods and added sugars.

The study’s scientists aren’t going in with any particular hypotheses about which foods are best. Instead, they will take the vast amounts of data they are collecting to create algorithms that, they hope, can predict what a particular diet will do for any one of us.

“I thought it would be nice if I could do something meaningful for, like, science and, personally, just to learn more about diet and how it affects me personally,” said Elizabeth, who works in technology at a company that rents out heavy equipment to businesses.

Since he works remotely from his Baton Rouge home, his schedule hasn’t changed much during the study. But he misses his fiancée, who’s a nurse elsewhere at Pennington Biomedical, and their two cats.

Photo Editor: Elena Scotti

Produced by Brian Patrick Byrne

 Read more