The results of the three-year-long Framingham Food Study were revealed on Friday, Nov. 16.
The panel presentation was led by co-principal investigators Cara Ebbeling and David Ludwig, co-directors of the New Balance Foundation Obesity Prevention Center. They work in the endocrinology department of the Boston Children’s Hospital, which performed the study in partnership with FSU.
The main conclusions of the study were that low-carbohydrate diets help to maintain weight loss, but most people who go on diets end up regaining the lost weight within one to two years, according to the panelists.
Ludwig said, “This is the largest and longest feeding study to test the ‘Carbohydrate-Insulin Model,’ which provides a new way to think about and treat obesity.”
Also known as FS(2), the study was funded with an $11 million grant provided from the Nutrition Science Initiative, according to Patricia Luoto, FSU professor emerita for food and nutrition, who also served as the on-campus project director.
According to the U.S. National Library of Medicine, the study was intended to “evaluate the effects of dietary composition on energy expenditure and chronic disease risk factors, while also exploring physiological mechanisms underlying these effects.”
Ludwig said according to the Carbohydrate-Insulin Model, “the processed carbohydrates that flooded our diets during the low-fat era have raised insulin levels, driving fat cells to store excessive calories.
“With fewer calories available to the rest of the body, hunger increases and metabolism slows – a recipe for weight gain,” he said.
All participants underwent a “selective process” to determine whether they were eligible to partake in the study, according to Luoto. The criteria mandated all participants to have a Body Mass Index of greater than 25 and be between the ages of 18 and 65.
According to a University press release, there were 1,685 potential participants. Ebbeling, Ludwig, and colleagues enrolled 234 participants in the study for an “initial weight-loss diet” spanning 10 weeks.
Their goal was to lose 10 to 14 percent of original body weight, the press release states. A total of 164 participants were successful in doing so and moved onto the “maintenance” phase of the study, during which participants ate a carbohydrate-controlled diet.
Participants could eat nothing except the provided meals and snacks from Sodexo, the University’s food service provider. They were also required to refrain from consuming alcohol.
“Sodexo did an exemplary job,” Luoto said.
Luoto said there were three cohorts of study participants – one for each year of the study. The first cohort began their diets in September 2014, with each diet lasting for a 20-week period. The last cohort finished in May 2017.
The first year was limited to FSU students, faculty, and staff, while the following years expanded to the MetroWest Area and “satellite areas” of the Boston Children’s Hospital, Luoto added.
Luoto also said Framingham State was chosen for the study for many reasons.
“The first reason – and the researchers will tell you this first and upfront – is because of the food and nutrition department at Framingham State,” Luoto said.
She added the University’s “locale” was also a contributing factor. Many similar studies have been performed in hospital environments, which would have not been conducive to the scope and length of this study, she said.
“They knew that realistically, financially, logistically – that simply wasn’t possible,” Luoto said.
Sites like universities are considered by researchers to be a “free-living environment,” according to Luoto. “There are other outlets that are available to [participants] – they weren’t trying to make it purist, trying to make you come in and admit yourself for x number of weeks or months.”
Luoto added Framingham State’s location and proximity to Boston also proved convenient for participants and researchers alike.
“They didn’t really want the study to be held at a university in Boston, because they felt that the number of outlets that would be available in terms of food and entertainment might have made it more difficult for participants to stick to the diet,” Luoto said.
Luoto said the renown of Framingham State in the research scene due to the successes of the Framingham Heart Study and FS(2) have made it a possible site for future studies.
The scope of the study did not include the effect of exercise and physical activity as contributing factors to weight loss. “Participants were told they could continue with their current exercise regimens,” Luoto said, but varsity athletes and marathon participants were not eligible to participate.
“There were not any ancillary studies done, but I do think it would be interesting to look at,” Luoto said.
Linda Vaden-Goad, provost and vice president for academic affairs, said, “We have been planning this event since the beginning of the study. We wanted to make sure that everyone that participated got to find out how they did during the food science study.
“We are very excited,” she added. “This study is the landmark study. I am excited for Framingham.”
FSU President F. Javier Cevallos said, “I thought the event was fascinating. It was very engaging, the way that they presented it.”
He added in the press release, “I am extremely proud of our community’s participation in this important study. Everyone involved has played a role in improving society’s understanding of dieting and weight-loss management.”