“Biggest Loser” study finds diet and exercise can sustain weight loss
Researchers have studied the effect of daily strenuous exercise and a restricted diet by examining data from a reality TV program.
Akinso: According to an NIH study, an exercise and diet combination is more effective for weight loss than just dieting alone. Researchers used data from the reality TV program “The Biggest Loser” for the study.
Hall: It's actually studying season eight of “The Biggest Loser” contestants.
Akinso: Dr. Kevin Hall is from the National Institute of Diabetes and Digestive and Kidney Diseases, part of the NIH, and he's the senior investigator of the study.
Hall: The way we got involved in this study was as most of the viewers who have ever watched the show probably knows that people step on scales at the end of the week and seem to be losing substantial amounts of weight — really surprising amounts 10, 15, 20 pounds per week, which is much greater than we typically see in weight loss programs.
Akinso: Dr. Hall explains that the shows' contestants were voluntary participants in the study.
Hall: So we went out to California during season eight with a group of investigators to really try to understand better what was going on metabolically when these obese participants were participating in this pretty intensive lifestyle intervention to lose substantial amounts of weight over a short period of time.
Akinso: Researchers measured body fat, total energy expenditure and resting metabolic rate — the energy burned during inactivity.
Hall: So I really wanted know, how many calories were they burning? How many calories were they eating? How much of the weight that is being lost is fat tissue versus lean tissues like muscle and things like that? So we got involved with the physician responsible for the care of the contestants on the show. And designed a study to go out there and measure changes in body composition, that's how much fat mass versus lean mass, is being changed as a result of this intervention as well as how many calories in total they're burning but before they started the program at six weeks into the program as well as at the end of the competition phase which is about seven months after they started.
Akinso: Dr. Hall used a mathematical computer model of metabolism — currently intended for research conducted by scientists and health professionals — to calculate the diet and exercise changes underlying the observed body weight loss.
Hall: What my lab at NIDDK is interested in doing is building computer simulation models of how we can put these data together in a way that helps us better understand the physiology of weight loss, the physiology of metabolic change as well as the physiology of how the body fat verses lean tissue is regulated.
Akinso: Because the TV program was not designed to directly address how exercise and diet interventions each contributed to the weight loss, the computer model simulated the results of diet alone and exercise alone to estimate their relative contributions.
Hall: Once we put the data together in our model and we tested the model to see if it was accurately matching data and which it was we then could run some what if scenarios and say what if instead of them doing both the exercise and the diet, what if they only did one or the other. And so we ran that simulation and we found that the diet alone would actually have led to more weight loss than exercise alone but actually less fat loss. And there were a couple of reasons for that one is because exercise really helps preserve that lean tissue that muscle tissue. And as a result the exercise its self is also burning calories as well. And so while you don’t lose as much weight with the exercise alone you lose more fat compared to if you just done the diet alone and stayed a sedentary lifestyle.
Akinso: More than two-thirds of U.S. adults age 20 and older are overweight or obese, and more than one-third of adults are obese. Being overweight or obese can lead to type 2 diabetes, heart disease, high blood pressure, stroke and cancers. For more information on this study, visit www.niddk.nih.gov. For NIH Radio, this is Wally Akinso For NIH Radio, this is Wally Akinso – NIH... Turning Discovery Into Health®.
About This Audio Report
Reporter: Wally Akinso
Sound Bite: Dr. Kevin Hall
Topic: obese, obesity, exercise, diet, biggest, loser, reality, TV, program, overweight, weight, loss, body, diabetes, high, blood, pressure, heart, disease