Calories, not protein, boost body fat: study

Published : Jan 4, 2012 - 11:29 Updated : Jan 4, 2012 - 11:30

People who eat too much of a high-calorie, low-protein diet tend to gain more body fat than people who overeat high amounts of protein, US researchers said Tuesday.

A study published in the January 4 issue of the Journal of the American Medical Association included 25 people in Louisiana who agreed to live as in-patients in a weight-gain experiment for a 56-day period.

Over the course of about two months, they were overfed by about 1,000 calories per day.

Calories are listed next to menu items in a McDonald`s restaurant in New York City in 2008. (AFP)

Some were fed a diet that was five percent protein, some ate 15 percent protein -- considered a normal level -- and others ate 25 percent protein, or a high amount.

The researchers' aim was to uncover how different levels of protein might affect overall weight gain, body fat and energy expenditure.

They found that people on the low-protein diet gained less weight overall, but that more of their extra energy was stored as fat than people on the mid-level and high-protein diets.

Low-protein eaters gained about half as much as the others -- putting on an average of 3.16 kilograms (seven pounds) during the study compared to 6.05 kg in the normal protein group and 6.51 kg in the high-protein group.

But a lot of that extra weight was in the form of lean body mass, which people on the mid- and high-level protein diets gained while those on the low-protein regime lost.

Ninety percent of the extra energy consumed by people on the low-protein diet was stored as fat, compared to about 50 percent in the other two groups.

"The key finding of this study is that calories are more important than protein while consuming excess amounts of energy with respect to increases in body fat," said the research, led by George Bray of the Pennington Biomedical Research Center in Baton Rouge, Louisiana.

<한글기사>

체지방 증가 주범은 칼로리

(연합뉴스) 체지방을 증가시키는 주범은 단백질 섭취량이 아니라 전체적인 칼로리 섭취량이라는 연구결과가 나왔다.

미국 페닝턴 생의학연구소(Pennington Biomedical Research Center)의 조지 브 레이(George Bray) 박사는 단백질을 적게 먹어도 전체적인 칼로리 섭취량이 지나치면 단백질을 많이 먹는 것보다 체지방이 더 많이 늘어난다고 밝힌 것으로 AFP통신 등이 3일(현지시간) 보도했다.

브레이 박사는 젊고 건강한 지원자 25명을 실험공간에서 56일 동안 살게 하면서 매일 적정 수준보다 1천 칼로리를 더 먹게 했다.

다만 이들을 3그룹으로 나누어 전체 칼로리 중 단백질이 차지하는 비율을 각각 5%(과소), 15%(정상), 25%(과다)로 달리해 이것이 전체적인 체중, 체지방, 에너지 연소에 어떤 영향을 미치는지를 비교했다.

그 결과 모두 체중이 늘었으나 저단백 그룹이 평균 3.16kg으로 중간단백 그룹의 6.05kg, 고단백 그룹의 6.51kg에 비해 거의 50%가 덜 늘어난 것으로 나타났다.

그러나 저단백 그룹은 칼로리 과다섭취로 늘어난 에너지의 90%가 체지방으로 쌓 이고 지방을 뺀 체중인 제지방체중(lean body mass)은 줄었다.

이에 비해 중간-고단백 그룹은 50%만이 체지방으로 저장되고 제지방체중이 늘었다.

이 연구결과는 미국의사협회 저널(Journal of American Medical Association) 최신호(1월4일자)에 실렸다.