He said the excitement lies in the purpose. Over the course of three two-week periods, Hamdorf agreed to be the study subject of a project aimed at answering questions that vex almost everyone who puts a fork to their mouth: What will happen to my body after I eat this food? Will it make me fat, raise my cholesterol, disrupt my gut microbiome, or perhaps extend my life?
The Nutrition for Precision Health Study, a $170 million national research project that aims to enroll 10,000 people across the country, aims to develop a way to determine the optimal diet for each person. The study is being conducted by six clinical centers across the country, including the New England Clinical Center led by Tufts University and Massachusetts General Hospital.
Current nutritional recommendations are based on averages of what works best for most people. But in many studies, people eating the exact same mixture of nutrients respond differently on measures like blood sugar or blood pressure, explains Holly Nicastro, program director of the national study.
The study will seek to find out exactly why this is so that one day people will hopefully be able to follow a diet that suits their unique biology.
The study also aims to overcome long-standing challenges in nutrition research. Typically, nutritional data is based on asking people what they remember eating. But memories are notoriously inaccurate and often biased by, for example, the embarrassment of having eaten the entire arm of an Oreo. Nutrition for Precision Health is testing other methods of documenting what people consume, including an app, a survey, or a small camera mounted on glasses and activated by chewing.
“We have the technology to really move away from the reliance on memory,” said Sarah L. Booth, director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “This is one of the exciting aspects of this study. We may be completely revolutionizing the way we study nutrition.
Participants first complete a “module” in which they track their normal diet for 10 days and report what they eat. If they want to continue, they choose to either buy pre-packaged meals to eat at home or enroll in a “living diet” module, a tightly controlled stay that Hamdorf has chosen. By keeping people indoors and under surveillance, researchers can precisely and precisely track what people eat and what effects those foods have on the body.
Hamdorf was among the inaugural group of four participants in the live diet phase in Boston. All were previously enrolled in the National Institutes of Health’s All of Us Research Program; This program aims to have 1 million or more participants contribute their health data, including genetics, to create a database that can inform thousands of studies. Only current All of Us members are invited to the nutrition workshop.
On the first day, participants were given blood and saliva samples, their bones were scanned, their metabolic rate was measured, and their fat/muscle ratio was documented. They were also equipped with blood glucose monitors worn around their waists to constantly monitor blood sugar fluctuations and wrist bands that track activity and sleep.
The next day, daily routines began: Weight and vital signs were taken at 6:30 a.m.; breakfast at 8 am; 12:00 lunch; 3 snacks in the afternoon; 18.00 dinner; 23:00 lights out.
Hamdorf said the rigorous schedule was liberating rather than limiting. “It’s a great feeling to be structured like this,” he said. “You just come for the food and you don’t have to go shopping or anything.”
Between meals and testing, participants were free to use exercise equipment on the 13th floor, lie on mats in the yoga room, gather in the game room, or relax in their spacious private room with panoramic windows. They loved interacting with many of the 150 people who work in the offices, laboratories and kitchen of the Human Nutrition Research Center on Aging.
They occasionally went for walks outside, but only when a staff member could accompany them, so that no one would feel the urge to eat an ice cream cone; researchers must be able to confirm that participants only ate what was served to them inside.
So what were they served?
Near the end of their first two-week assignment, at noon, the four participants went to the 11th-floor dining room, accompanied by clinical research director Paul J. Fuss, who kept an eye on them while they ate.
The kitchen staff brought them plates wrapped in plastic with their names on them. Each meal is tailored to the individual’s caloric needs; Participants are not expected to gain or lose weight.
Each also includes a small rubber spatula to catch every crumb. “We want you to lick the plate without licking the plate,” said dietitian Kayla Airaghi. If they can’t finish it, staff will weigh the leftovers and track consumption to the 10th of a gram.
On this day, Lori Mattheiss, 60, of Andover, bought burgers, peaches and potato chips; Her husband, Tim Carter, 63, was served two hamburger sliders. Jane Cashell, 75, of Clinton, ate broccoli, chicken nuggets and macaroni and cheese. Hamdorf was given Spanish rice, taco spicy chicken and cheddar cheese.
“This is not the food we normally eat,” Mattheiss said. “I’m eating things I haven’t eaten since I was a kid.” Other days he drank Yodel, Kool-Aid, canned fruit punch, and Fritos.
In this two-week session, participants followed what they called the traditional American diet. But researchers resist labeling it; It is officially defined only by its content; high in refined grains and sugar-sweetened beverages and low in fruits, vegetables, whole grains and fish.
During the second and third two-week visits, separated by at least two weeks, participants ate high-fat and high-protein foods and finally followed a diet full of fruits, vegetables, beans and nuts. whole grains and fish (all four liked this best).
The three diets were chosen not because they were recommended, but because they are the most common dietary patterns in the United States, said Sai Krupa Das, principal investigator of the New England branch of the study and a senior scientist at the center. “These reflect what we consume as a nation,” he said.
The goal is not to determine which diet is best, but to measure the different responses individuals have to different ingredients.
Researchers acknowledge that it will be difficult to attract diverse populations to this phase of the project. How many people can put their lives on hold for two weeks at a time? Carter and Mattheiss, who trade stocks online, worked during their stay, and other remote workers may do the same. What about bus drivers? Restaurant owners? Parents of young children? Even the $6,200 stipend for completing all three two-week sessions may not be enough to make up for lost work.
Despite the challenges, NIH’s Nicastro said, “We have ambitious diversity goals,” and they hope to achieve that with at least “Module 1,” in which participants eat and record what they normally do. But even for the more challenging modules—prepackaged meals or residential dieting—research sites are working with churches, barbershops, community centers and other places to enroll people in All of Us and then enroll them in the nutrition study. , said Nicastro.
Rafael Pérez-Escamilla, a professor at the Yale School of Public Health who was not involved in the research, believes Nutrition for Precision Health will likely answer some fascinating scientific questions — but he said it won’t do much to help development. to reach people’s health or those suffering from the worst effects of malnutrition.
“We live in a country where nearly 70 percent of adults are overweight or obese and 70 percent or more of their calories come from overly processed or junk foods, including sugar-sweetened beverages,” he said. “The problem is heavily concentrated among the poor.”
Pérez-Escamilla would much prefer to see similar investment in efforts to increase access to healthy foods, such as “producing prescription programs” that provide debit cards to purchase fresh fruits and vegetables.
Stanford professor Christopher Gardner, who studies the health benefits of dietary ingredients but was not involved in the Nutrition for Precision Health study, called it an “incredibly ambitious” project. He predicted that researchers would identify good and bad bacteria in the gut and which foods support them.
Gardner serves on the scientific advisory board of Zoe, a privately held company that provides personalized nutritional advice based on biological information. People take tests at home and receive instructions on what to eat based on the results.
That’s exactly what the NIH study hopes to ultimately deliver, but Das, the principal investigator in Boston, said the results will have stronger scientific support. “The market is always ahead of the science,” he said when asked about Zoe.
At the end of their two-week stay, participants face two full days of testing in which every aspect of their biology is measured. On the final day, they drink two cups of Vanilla Water and sit in a chair from 8 a.m. to 1 p.m., giving blood samples at regular intervals to measure how nutrients are being metabolized.
The “living diet” sessions are expected to be completed by mid-2026. Then, with a trove of data from each individual, replicated across thousands of participants, the project will use AI to come up with recommended algorithms to determine who should eat what. But this is not the end: a series of studies will need to be carried out to validate these algorithms.
Nicastro is keen to learn what factors drive individual responses. “It could be genetics, it could be the microbiome, it could be something environmental, or possibly a lot of these things are mixed together,” he said. The ultimate goal is to have doctors or dietitians test certain factors and then create a personalized nutrition plan.
Meanwhile, the first four participants, who settled into their homes with lime green souvenir water bottles, are already finding themselves making changes to their diets. Cashell loved the third diet so much that she’s trying to recreate the recipes in her kitchen. Hamdorf noticed that he never felt hungry during the experiment, but looked forward to each meal and realized he needed to eat more and drink more water. Matthyess and Carter try to eat less in the evening and include more fruits and nuts.
Everyone was happy to be a part of the study.
“You don’t have many opportunities to contribute to important scientific research,” Carter said. “And I feel lucky to be able to do that.”
Felice J. Freyer can be reached at felice.freyer@globe.com. follow him @felicejfreyer.