Week 42 in the tea study and Adam Sharpe is dreaming of white pizza and beer.
Since mid-October nearly every morsel of food the 26-year-old Hyattsville landscaper has eaten has been prepared by cooks at the Beltsville Human Nutrition Research Center.
On weekdays, Sharpe has eaten his breakfasts and dinners in a small, drab cafeteria on the research center's campus. His lunches and weekend meals - even his Thanksgiving turkey - were precisely measured and packed for him to take home. And he has drunk tea, or a beverage that tastes like tea, five times a day, every day.
"I had to change my whole lifestyle," said Sharpe. Such are the sacrifices for science.
Here in Building 308, a three-story brick structure on a campuslike setting in Beltsville, U.S. Department of Agriculture scientists are toiling to find answers to today's most pressing food and nutrition questions: How much are Americans really eating? Why are we getting so fat? Do compounds found in tea, watermelon, barley and other foods really fight disease? What is the effect of diet on cancer, heart disease, diabetes and osteoporosis?
The folks at the lab are the ones who warned you about the artery-clogging components of butter and vegetable shortening. They documented the benefits some women derived from alcohol and showed that watermelon is a good source of disease-fighting lycopene.
In the tea study, they are trying to find out whether components found in black tea can reduce the damage smoking causes to blood vessels.
Studies typically run for several weeks and involve 20 to 40 participants who are paid anywhere from a few hundred dollars to several thousand dollars for their time and trouble. But some research involves hundreds of participants in studies that can go on for a year.
"There are not a lot of places in the country that can do the large studies, and that's what we're doing here," said researcher David J. Baer.
About 200 full- and part-time employees work at the center. Research is funded by food giants such as Kraft and Unilever, nonprofit agencies and tax dollars, but Baer said scientists feel no pressure to skew their reports to benefit their sponsors. "The data are what the data are," he said.
And sometimes the data point to surprising conclusions. Despite well-publicized reports about the health benefits of chemicals found in tea, red wine and blueberries, Baer said the research center so far has found very little proof to back up the claims.
Even such common-sense notions that exercise can help a person lose weight may not be true, said researcher William V. Rumpler, who is investigating whether high-fat diets actually make a person fat. Increased exercise often leads to increased eating, and no weight loss at all, he says.
Building 308 holds a mishmash of laboratories, conference rooms and offices. There are two cafeterias with two cooks in charge of preparing meals for the research studies. One is Diana Shegogue, who doesn't fancy herself a chef so much as a partner in research.
Her kitchen resembles that of a school cafeteria - stainless-steel tables, industrial gas stove and ovens. The food is similar, too.
While the quality of ingredients she uses in her meals is top-notch, Shegogue said the scientists strictly control the menu and portions, and the food she prepares is by necessity bland. No flourishing squiggles of sauces on these plates, although Shegogue said she tries to make the meals as appetizing as possible.
"We want them to eat the food and not cheat," she explains.
Although some experiments require the kitchen staff to follow exacting recipes and precisely measure portions, two studies starting this month will not require as much work from the kitchen crews.
One is designed to find out whether chips made from red potatoes are more healthful than those made from white potatoes. Participants will eat a 2-ounce bag of chips with their lunch and another with dinner, and on one occasion with breakfast, for several days during the course of a month. They will eat their meals at home.
"People were very excited about eating potato chips," said Anne Kurilich, one of the researchers who interviewed participants for the study.
The other study may be a bit less appetizing. Scientists will explore whether purple carrots are more healthful than orange ones. Participants will drink the juice from the purple carrots for several days over the course of two months. A few of their meals will be packed by the nutrition center's kitchen staff.
Not all of the studies require feeding subjects, however.
Researchers also are studying how people burn calories. One room at the center is equipped with a bed and a small boxlike device that measures the calories a person is using while resting.
In another room, there are two sealed chambers in which subjects spend up to 23 1/2 hours a day so that scientists can determine how many calories are expended during normal activities.