"Long before it's in the papers"
January 27, 2015


Cutting carbs may be better than cutting fat for weight loss

Sept. 2, 2014
World Science staff

Cut­ting high-car­bo­hy­drate foods may be more ef­fec­tive than cut­ting fat for weight loss and car­di­o­vas­cu­lar health, a new study finds.

Sci­en­tists said the re­sults sur­pris­ingly showed that peo­ple who don’t re­duce their fat in­take none­the­less can lose weight and re­duce their risk fac­tors for heart dis­ease. That chal­lenges a long-prevailing view that a low-fat di­et is the key to bet­ter health for most.

The study en­rolled 148 men and wom­en with­out clin­i­cal car­di­o­vas­cu­lar dis­ease and di­a­be­tes, of which half were in­structed to lim­it their in­take of car­bo­hy­drate-rich foods, which in­clude sug­ary foods, grains, ce­reals and starches. The oth­ers were in­structed to re­duce their fat in­take, which they did by cut­ting it to less than 30 per­cent of their daily en­er­gy in­take, ac­cord­ing to the re­search­ers.

The par­ti­ci­pants, an eth­nic­ally di­verse group, weren’t asked to lim­it their over­all cal­o­rie con­sump­tion.

The in­ves­ti­ga­tors col­lect­ed da­ta on weight, car­di­o­vas­cu­lar risk fac­tors, and di­etary com­po­si­tion at the be­gin­ning and end of a one-year pe­ri­od, and al­so at three and six months.

“The low-car­bo­hy­drate di­et was more ef­fec­tive for weight loss and car­di­o­vas­cu­lar risk fac­tor re­duc­tion than the low-fat di­et,” wrote the sci­en­tists, Lyd­ia Baz­zano of the Tu­lane Uni­vers­ity School of Pub­lic Health and Trop­i­cal Med­i­cine in New Or­leans and col­leagues, re­port­ing their re­sults Sept. 2 on­line in the jour­nal An­nals of In­ter­nal Med­i­cine. “Re­strict­ing car­bo­hy­drate may be an op­tion for per­sons seek­ing to lose weight and re­duce car­di­o­vas­cu­lar risk fac­tors.”

“Low-car­bo­hy­drate di­ets are pop­u­lar for weight loss, but their car­di­o­vas­cu­lar ef­fects have not been well-stud­ied, par­tic­u­larly in di­verse popula­t­ions,” the re­search­ers al­so wrote. They added that partici­pants in the low-carb group saw great­er in­creas­es in HDL cho­lest­erol, the so-called “good” cho­lest­erol.

Dar­iush Mozaf­far­ian, the dean of the Fried­man School of Nu­tri­tion Sci­ence and Pol­i­cy at Tufts Uni­vers­ity in Massa­chu­setts, who was­n’t in­volved in the stu­dy, told the New York Times that “to my knowl­edge, this is one of the first long-term tri­als that’s giv­en these di­ets with­out cal­o­rie re­stric­tions,” said. “It shows that in a free-liv­ing set­ting, cut­ting your carbs helps you lose weight with­out fo­cus­ing on cal­o­ries. And that’s really im­por­tant be­cause some­one can change what they eat more easily than try­ing to cut down on their cal­o­ries.”

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Cutting carbohydrates may be more effective than cutting fat when it comes to weight loss and cardiovascular health, a new study finds. Scientists said the results surprisingly showed that people who don’t reduce their fat intake nonetheless lose weight and reduce their risk factors for heart disease. That challenges a long-prevailing view that a low-fat diet is the key to better health for most. The study enrolled 148 men and women without clinical cardiovascular disease and diabetes, of which half were instructed to limit their intake of carbohydrate-rich foods, which include sugary foods, grains, cereals and starches. The others were instructed to reduce their fat intake, which they did by cutting it to less than 30 percent of their daily energy intake, according to the researchers. The participants, an ethnically diverse group, weren’t asked to limit their overall calorie consumption. The investigators collected data on weight, cardiovascular risk factors, and dietary composition at the beginning and end of a one-year period, and also at three and six months. “The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet,” wrote the scientists, Lydia Bazzano of the Tulane University School of Public Health and Tropical Medicine in New Orleans and colleagues, reporting their results Sept. 2 online in the journal Annals of Internal Medicine. “Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.” “Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations,” the researchers also wrote. Dariush Mozaffarian, the dean of the Friedman School of Nutrition Science and Policy at Tufts University, who wasn’t involved in the study, told the New York Times that “to my knowledge, this is one of the first long-term trials that’s given these diets without calorie restrictions,” said. “It shows that in a free-living setting, cutting your carbs helps you lose weight without focusing on calories. And that’s really important because someone can change what they eat more easily than trying to cut down on their calories.”