NIH Studies “The Biggest Loser”

The pro­gram shows obese adults los­ing large amounts of weight over sev­eral months. Participants were ini­tially iso­lated on a ranch fol­lowed by an extended period at home.

“By includ­ing the show’s con­tes­tants as vol­un­tary study par­tic­i­pants, this research took advan­tage of a cost-efficient oppor­tu­nity to study a small group of obese indi­vid­u­als already engaged in an inten­sive lifestyle inter­ven­tion,” said Hall, who has no finan­cial ties and no other affil­i­a­tion to the show.

Researchers mea­sured body fat, total energy expen­di­ture and rest­ing meta­bolic rate—the energy burned dur­ing inactivity—three times: at the start of the pro­gram, at week 6, and at week 30, which was at least 17 weeks after par­tic­i­pants returned home. Participation in the pro­gram led to an aver­age weight loss of 128 pounds, with about 82 per­cent of that com­ing from body fat, and the rest from lean tis­sue like mus­cle. Preserving lean tis­sue, even dur­ing rapid and sub­stan­tial weight loss, helps main­tain strength and mobil­ity and reduces risk of injury, among other benefits.

Hall used a math­e­mat­i­cal com­puter model of human metabolism—currently intended for research con­ducted by sci­en­tists and health professionals—to cal­cu­late the diet and exer­cise changes under­ly­ing the observed body weight loss. Because the TV pro­gram was not designed to directly address how the 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.

At the competition’s end, diet alone was cal­cu­lated to be respon­si­ble for more weight loss than exer­cise, with 65 per­cent of the weight loss con­sist­ing of body fat and 35 per­cent con­sist­ing of lean mass like mus­cle. In con­trast, the model cal­cu­lated that exer­cise alone resulted in par­tic­i­pants los­ing only fat, and no mus­cle. The sim­u­la­tion of exer­cise alone also esti­mated a small increase in lean mass despite over­all weight loss.

The sim­u­la­tions also sug­gest that the par­tic­i­pants could sus­tain their weight loss and avoid weight regain by adopt­ing more mod­er­ate lifestyle changes—like 20 min­utes of daily vig­or­ous exer­cise and a 20 per­cent calo­rie restriction—than those demon­strated on the tele­vi­sion program.

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. Excess weight can lead to type 2 dia­betes, heart dis­ease, high blood pres­sure, stroke, and cer­tain cancers.

“This study rein­forces the need for a healthy diet and exer­cise in our daily lives,” said NIDDK Director Dr. Griffin P. Rodgers. “It also illus­trates how the sci­ence of metab­o­lism and math­e­mat­i­cal mod­el­ing can be used to develop sound rec­om­men­da­tions for sus­tain­able weight loss—an impor­tant tool in the treat­ment of obesity—based on an individual’s unique circumstances.”

The NIDDK, a com­po­nent of the NIH, con­ducts and sup­ports research on dia­betes and other endocrine and meta­bolic dis­eases; diges­tive dis­eases, nutri­tion and obe­sity; and kid­ney, uro­logic and hema­to­logic dis­eases. Spanning the full spec­trum of med­i­cine and afflict­ing peo­ple of all ages and eth­nic groups, these dis­eases encom­pass some of the most com­mon, severe and dis­abling con­di­tions affect­ing Americans. For more infor­ma­tion about the NIDDK and its pro­grams, see www.niddk.nih.gov.

Source: NIH release.