Low carb? Low fat? What lat­est diet stud­ies say

The Idaho Statesman (Sunday) - - NEWS - BY CANDICE CHOI As­so­ci­ated Press NEW YORK

Ba­con and black cof­fee for break­fast, or oat­meal and ba­nanas?

If you’re plan­ning to try to lose weight in 2019, you’re sure to find a fierce de­bate on­line and among friends and fam­ily about how best to do it. It seems like ev­ery­one has an opin­ion, and new fads emerge ev­ery year.

Two ma­jor stud­ies last year pro­vided more fuel for a par­tic­u­larly po­lar­iz­ing topic – the role carbs play in mak­ing us fat. The stud­ies gave sci­en­tists some clues, but, like other nu­tri­tion stud­ies, they can’t say which diet – if any – is best for ev­ery­one.

That’s not go­ing to sat­isfy peo­ple who want black-and-white an­swers, but nu­tri­tion re­search is ex­tremely dif­fi­cult and even the most re­spected stud­ies come with big caveats. Peo­ple are so dif­fer­ent that it’s all but im­pos­si­ble to con­duct stud­ies that show what re­ally works over long pe­ri­ods of time.

Be­fore em­bark­ing on a weight loss plan for this year, here’s a look at some of what was learned last year.

Fewer carbs, fewer pounds?: It’s no longer called the Atkins Diet, but the low-carb school of di­et­ing has been en­joy­ing a come­back. The idea is that the re­fined car­bo­hy­drates in foods like white bread are quickly con­verted into sugar in our bod­ies, lead­ing to en­ergy swings and hunger.

By cut­ting carbs, the claim is that weight loss will be eas­ier be­cause your body will in­stead burn fat for fuel while feel­ing less hun­gry. A re­cent study seems to of­fer more sup­port for low-carb pro­po­nents. But, like many stud­ies, it tried to un­der­stand just one sliver of how the body works.

The study , co-led by an au­thor of books pro­mot­ing low-carb di­ets, looked at whether vary­ing carb lev­els might af­fect how the body uses en­ergy. Among 164 par­tic­i­pants, it found those on low-carb di­ets burned more to­tal calo­ries than those on high-carb di­ets.

The study did not say peo­ple lost more weight on a low-carb diet – and didn’t try to mea­sure that. Meals and snacks were tightly con­trolled and con­tin­u­ally ad­justed so ev­ery­one’s weights stayed sta­ble.

David Lud­wig, a lead au­thor of the pa­per and re­searcher at Bos­ton Chil­dren’s Hos­pi­tal, said it sug­gests lim­it­ing carbs could make it eas­ier for peo­ple to keep weight off once they’ve lost it. He said the ap­proach might work best for those with di­a­betes or pre-di­a­betes.

Lud­wig noted the study wasn’t in­tended to test long-term health ef­fects or real-world sce­nar­ios where peo­ple make their own food. The find­ings also need to be repli­cated to be val­i­dated, he said.

Caro­line Apo­vian of Bos­ton Uni­ver­sity’s

School of Medicine said the find­ings are in­ter­est­ing fod­der for the sci­en­tific com­mu­nity, but that they shouldn’t be taken as ad­vice for the av­er­age per­son look­ing to lose weight.

Do I avoid fat to be skinny?: For years peo­ple were ad­vised to curb fats , which are found in foods in­clud­ing meat, nuts, eggs, but­ter and oil. Cut­ting fat was seen as a way to con­trol weight, since a gram of fat has twice as many calo­ries than the same amount of carbs or pro­tein.

Many say the ad­vice had the op­po­site ef­fect by in­ad­ver­tently giving us li­cense to gob­ble up fat­free cook­ies, cakes and other foods that were in­stead full of the re­fined carbs and sug­ars now blamed for our wider waist­lines.

Nu­tri­tion ex­perts grad­u­ally moved away from blan­ket rec­om­men­da­tions to limit fats for weight loss. Fats are nec­es­sary for ab­sorb­ing im­por­tant nu­tri­ents and can help us feel full. That doesn’t mean you have to sub­sist on steak driz­zled in but­ter to be healthy.

Bruce Y. Lee, a pro­fes­sor of in­ter­na­tional health at Johns Hop­kins, said the lessons learned from the anti-fat fad should be ap­plied to the anti-carb fad: don’t over­sim­plify ad­vice.

Which is bet­ter?: An­other big study this past year found low-carb di­ets and low-fat di­ets were about equally as ef­fec­tive for weight loss. Re­sults var­ied by in­di­vid­ual, but af­ter a year, peo­ple in both groups shed an av­er­age of 12 to 13 pounds.

The au­thor noted the find­ings don’t con­tra­dict Lud­wig’s low-carb study. In­stead, they sug­gest there may be some flex­i­bil­ity in the ways we can lose weight. Par­tic­i­pants in both groups were en­cour­aged to fo­cus on min­i­mally pro­cessed foods like pro­duce and meat pre­pared at home. Ev­ery­one was ad­vised to limit added sugar and re­fined flour.

“If you got that foun­da­tion right, for many, that would be an enor­mous change,” said Christo­pher Gard­ner of Stan­ford Uni­ver­sity and one of the study’s au­thors.

Lim­it­ing pro­cessed foods could im­prove most di­ets by cut­ting down over­all calo­ries, while still leav­ing wig­gle room for peo­ple’s pref­er­ences. That’s im­por­tant, be­cause for a diet to be ef­fec­tive, a per­son has to be able to stick to it.

Gard­ner notes the study had its lim­i­ta­tions, too. Par­tic­i­pants’ di­ets weren’t con­trolled.

Peo­ple were in­stead in­structed on how to achieve eat­ing a low-carb or low-fat in reg­u­lar meet­ings with di­eti­tians, which may have pro­vided a sup­port net­work most di­eters don’t have.

So, what works?: In the short term you can prob­a­bly lose weight by eat­ing only raw foods, or go­ing ve­gan, or cut­ting out gluten, or fol­low­ing an­other diet plan that catches your eye. But what will work for you over the long term is a dif­fer­ent ques­tion.

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