最佳減肥法:低血糖指數飲食

A diet based on healthy carbohydrates-rather than a low-fat or low-carbohydrate diet-offers the best chance of keeping weight off without bringing unwanted side effects, a study published Tuesday in the Journal of the American Medical Association suggests.

《美國醫學學會雜誌》（Journal of the American Medical Association）6月26日刊登的一項研究報告指出，以健康碳水化合物爲主的飲食──而非低脂或低碳水化合物飲食──能達到最佳的減肥效果，並且不會帶來副作用。

Study participants following a low-glycemic-index diet, which is similar to a Mediterranean diet and focuses on fish, fruit, vegetables, nuts and whole grains, also saw improved cholesterol levels and other important markers that lower the risks of developing heart disease and diabetes. Such a diet might include minimally processed oatmeal, almonds, brown rice, beans and healthy fats like olive oil, among other foods.
研究發現，遵循低血糖指數飲食方案的研究對象的膽固醇水平及其他幾項降低罹患心臟病和糖尿病風險的重要指標也有所改善。低血糖指數飲食與地中海式飲食相似，主要食用魚類、水果、蔬菜、堅果和全穀物食品。該種飲食也可包括輕微加工過的燕麥片、杏仁、糙米、豆類和以橄欖油爲代表的健康油脂等食物。

The study was led by researchers at the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital and funded by the National Institutes of Health and the New Balance Foundation, which is affiliated with the athletic-shoe maker. It was designed to assess how each of three common diets affects the ability to keep weight off. Participants had all of their food prepared for them, and their food intake was monitored. They ate many meals at the hospital, picking up others to eat at home.
這項研究由波士頓兒童醫院（Boston Children's Hospital）新百倫基金肥胖預防中心（New Balance Foundation Obesity Prevention Center）的研究人員主導，由美國國立衛生研究院（National Institutes of Health）和運動鞋製造商新百倫旗下的新百倫基金會（New Balance Foundation）提供資助。研究旨在評估三種日常飲食方案對減肥效果的影響。研究對象只吃研究人員爲其準備的食物，他們的進食過程也受到監控。他們有時在醫院用餐，有時將食物帶回家吃。

David Ludwig, one of the study's authors and the director of the center, explained that most people struggle to keep weight off. Previous studies have shown that weight loss reduces the body's daily energy expenditure-or how many calories the body burns through activity and just by resting-making it easy to regain weight. Dr. Ludwig's study was designed to look at the impact of the three diets on measures of energy expenditure, in addition to assessing hormones, fat levels in the blood and other health markers.
研究報告作者之一、肥胖預防中心主任大衛•路德維希（David Ludwig）解釋說，大多數人都在費盡心機減肥。以往的研究已經證明，體重減輕會降低身體每日的能量支出──即身體通過活動或只是靜止不動燃燒掉的卡路里──這樣使得體重容易反彈。路德維希的研究旨在觀察三種飲食方案對熱量消耗量的影響，同時評估血液中的激素和脂肪水平以及其他的健康指標。The study's 21 participants, 18 to 40 years old, initially lost 10% to 15% of their body weight during a three-month diet that contained about 45% of total calories from carbohydrates, 30% from fat and 25% from protein.
21名研究對象年齡在18到40歲之間。他們在最初的三個月裏減掉了10%-15%的體重，這三個月裏他們遵循的飲食方案中45%的熱量來自碳水化合物，30%來自脂肪，還有25%來自蛋白質。

A month later, participants were placed on one of three diets for a month: a low-fat diet limiting fats to 20% of total calories; a low-carbohydrate diet modeled on the Atkins diet, limiting carbohydrate intake to 10% of total calories; and a low-glycemic-index diet, which contained 40% of total calories from carbohydrates, 40% from fats and 20% from protein. Participants were then switched to the other two diets during two additional four-week periods.
一個月後，他們分別開始遵循這三種飲食方案中的一種：低脂飲食，脂肪佔總熱量攝入的20%；阿特金斯飲食法（Atkins diet）的低碳水化合物飲食，碳水化合物的攝入量只佔總熱量攝入的10%；還有低血糖指數飲食，其中碳水化合物佔總熱量的40%，脂肪佔40%，蛋白質佔20%。四周後改爲下一種飲食方案，再過四周改爲第三種飲食方案。

"The low-fat diet had the worst effect" on energy expenditure, Dr. Ludwig said. Participants on that diet also had increases in triglycerides, a type of fat, and lower levels of so-called good cholesterol. "We should avoid severely restricting any major nutrient and focus on the quality of the nutrient," he said.
路德維希博士說，低脂飲食對增加能量支出的效果最差。遵循這種飲食方案的研究對象還出現了甘油三酯（一種脂肪）水平上升，所謂的有益膽固醇的水平也有所降低。他說，我們應當避免嚴格控制任何一種主要營養素，而應該注意保證營養素的質量。

Dr. Ludwig said those on the low-carb diet had the biggest boost in total energy expenditure, burning about 300 calories more per day than those on the low-fat diet-about the same as an hour of moderate exercise. But that bump came at a cost: increases in cortisol, a stress hormone, and a measure of inflammation called CRP, which can raise the risk of developing heart disease and diabetes.
路德維希博士說，遵循低碳水化合物飲食的研究對象總能量支出的增幅最大，每日消耗量比低脂飲食者多300卡路里左右──這幾乎等於一小時中等強度運動所消耗掉的能量。然而如此突出的效果是有代價的：應激素皮質醇水平升高，此外還導致一種名爲C反應蛋白（CRP）的炎症標誌物水平升高，它會增加罹患心臟病和糖尿病的風險。

Those on the low-glycemic-index diet burned about 150 calories a day more than those on the low-fat diet without any negative impacts on cholesterol levels or various hormones, making it the ideal diet, Dr. Ludwig said. The glycemic index measures the impact of carbohydrates on blood-sugar levels.
路德維希博士說，低血糖指數飲食者的日消耗熱量約比低脂飲食者多150卡路里，同時對膽固醇水平和各類激素水平沒有任何消極影響，這使它成爲理想的飲食結構。血糖指數衡量的是碳水化合物對血糖水平的影響。

A second study in the same medical journal showed that people in an 18-month weight-loss program that started with monthly meetings lost nearly as much weight as those in a much costlier program of the same duration with group sessions that initially met weekly. That study, led by researchers at the University of Pittsburgh, found that the monthly program cut about $600 off the cost of a $1,360 traditional weight-loss program with the weekly ers of the group taking monthly classes were mailed the same material as those who attended classes weekly, and those who failed to meet weight-loss goals could get individual counseling by phone or in person.
該雜誌刊登的另一項研究對兩種減肥課程的效果進行了研究：兩種課程均爲期18個月，一種是每月上課一次，另一種花費更貴、每週進行小組討論，結果發現參加兩種課程的人減掉的體重相差無幾。這項由匹茲堡大學（University of Pittsburgh）研究人員牽頭的研究發現，每月減肥課程的成本比傳統的每週減肥課程低600美元，後者花費爲1,360美元。參加每月課程的成員收到的材料與參加每週課程的人相同，未能達到減肥目標者可以獲得一對一的電話或面對面諮詢。