Every few months, a new study purports to prove that a calorie is a calorie is a calorie, and that the only way to lose weight is to burn more than you take in.

But veteran dieters know something that some researchers apparently don't: Certain foods seem to fuel the appetite like pouring gasoline on a fire. Some people find that once they start eating bread, cookies, chocolate -- or leftover Easter candy -- they lose all sense of fullness and find it difficult to stop.

That's the concept behind 'The Skinny,' a new book by Louis J. Aronne, director of the Comprehensive Weight Loss Program at NewYork Presbyterian Hospital/Weill Cornell Medical Center. 'It's true that a calorie is a calorie,' Dr. Aronne says. 'But what that doesn't take into account is how some calories affect what people eat later on.'

After 23 years of treating patients, Dr. Aronne has concluded that refined carbohydrates and foods with high sugar and fat content promote what he calls 'fullness resistance.' They interfere with the complex hormonal messages the body usually sends to the brain to signal that it's time to stop eating. People feel hungrier instead.

This happens in part because refined carbohydrates raise blood-sugar levels, setting up an insulin surge that drives blood sugar down again, causing rebound hunger. That insulin spike also interferes with leptin, the hormone secreted by fat cells that should tell the body to stop eating. Obese people have loads of leptin, but it either doesn't get to the brain, or the brain becomes resistant to it.

Other researchers have described similar phenomena. An article in this month's Medical Hypothesis argues that for some people, refined foods with high sugar and carbohydrate content can be just as addictive as tobacco and alcohol.

Eating foods high in protein, vegetables, fiber and water have the opposite effect, Dr. Aronne says. His plan recommends revising what you eat, one meal at a time, to restore your sense of fullness:

Breakfast: Loading up on lean protein -- ideally from egg whites or a protein shake -- in the morning reduces hunger all day long. Eating muffins, bread, sweetened cereal and juice does the opposite. A study of 30 overweight women at Saint Louis University School of Medicine found that those who ate eggs for breakfast consumed 140 fewer calories at lunch, and ate less for the next 36 hours, compared with women who ate bagels in the morning.

Lunch: Some dieters try to cut calories by skipping this meal. But going more than five hours without food causes hunger hormones to rise and fullness hormones to drop, and sends more of the calories consumed at dinner straight to fat cells. Dr. Aronne recommends starting lunch with a salad, then more vegetables, and then lean protein. Skip the cheese, bacon and creamy dressings, he advises. Using vinegar alone will cut your appetite and slow the rise in blood sugar.

Dinner. The end of the day is fraught with temptation. Obese people consume significantly more calories at dinner than slimmer people. Here, too, load up first on salads, clear soups, or high-protein appetizers like shrimp cocktail, then have a lean protein main course. Eating bread before dinner makes people lose their sense of fullness and eat more, Dr. Aronne warns. Alcohol makes it worse by lowering your resistance and promoting fat storage.

Not everyone agrees that consuming more protein cuts appetite. Harvard School of Public Health's Frank Sacks led a study published in the New England Journal of Medicine that compared 811 overweight adults on four diets with varying levels of protein, fat and carbohydrate. 'We found absolutely no difference in their satiety and hunger levels,' Dr. Sacks says.

All the groups lost similar amounts of weight. That's not surprising, other weight-loss experts say, since there were only modest differences in their fat, protein and carbohydrate intakes, and many participants didn't stick to their plans.

To be sure, if you eat as Dr. Aronne suggests, you'll consume fewer calories overall. The point is, eating protein early in the day may make it much easier to cut down.

每隔几个月就会有一项新研究试图证明卡路里就是热量，减肥的唯一途径就是让卡路里的消耗量超过摄入量。

但有经验的节食者知道一些研究人员显然不清楚的事情：某些食品似乎能够增进食欲，就象火上浇油一样。一些人发现，一旦他们开始吃面包、曲奇、巧克力──或是复活节剩下的糖果──他们的饱足感就会荡然无存，难以停嘴。

这就是纽约长老会医院/威尔•康奈尔医疗中心(NewYork Presbyterian Hospital/Weill Cornell Medical Center)综合减肥项目主任亚隆(Louis J. Aronne)的新书《瘦身》(The Skinny)中的理论。他说，卡路里就是热量这话说的没错，但这个观念没有考虑到一些卡路里如何影响人们随后的进食。

根据亚隆23年的从医经验总结，精制碳水化合物和高糖份和高脂肪含量的食品能够增进他所谓的“抵御饱足感”。这些食物会干扰人体通常向大脑发出的是时候停止进食的复杂荷尔蒙信息。因此，人就会感觉到更饥饿。

这其中的部分原因是，精制碳水化合物会提高血糖含量，促使胰岛素大量上升，再次降低血糖，进而引发饥饿感。胰岛素上升也会干扰脂肪细胞生成的瘦体素，这种荷尔蒙本应告诉人体停止进食。肥胖的人也有大量瘦体素，但要么这种荷尔蒙不作用于大脑，要么大脑对此没有反应。

其他研究人员也描述过类似的现象。医学期刊《Medical Hypothesis》本月刊登的一篇文章称，对某些人来说，高糖份和高碳水化合物的精制食品可以像烟和酒一样上瘾。

亚隆说，高蛋白食品、蔬菜、纤维和水则会产生相反的效果。他建议你调整三餐食谱，以恢复饱足感。

早餐：早上摄入精益蛋白质──最好是蛋清或是高蛋白饮品──可以降低一天的饥饿感。食用松饼、面包、加糖麦片和果汁则会起到相反的效果。圣路易斯大学医学院曾对30个体重超标的女性进行过研究，发现与早餐吃贝果（先蒸后烤的发面圈）的妇女相比，早餐吃鸡蛋的女性在中餐时会少摄入140卡路里的热量，未来36个小时的进食量也较少。

午餐：一些节食者试图不吃午餐来减少卡路里摄入。但超过5个小时不进食会导致饥饿荷尔蒙上升以及饱足荷尔蒙下降，将更多晚餐时摄入的热量直接转化为脂肪细胞。亚隆建议午餐先吃份沙拉，再吃较多的蔬菜，然后是精益蛋白质。他建议别吃奶酪、培根和奶油沙拉酱。喝醋能够降低食欲，并延缓血糖浓度的上升。

晚餐：每天的最后一餐总是充满诱惑。与身材较瘦的人相比，肥胖的人晚餐明显会摄入更多热量。同样的，晚餐也先吃沙拉、清汤或是鸡尾酒虾等高蛋白开胃菜；然后再吃精益蛋白质的主菜。亚隆警告说，在晚餐之前吃面包会让人饱足感下降，加大食欲。酒精则会让情况更糟，因为这会降低你的抵制力，加速脂肪存储。

并不是所有人都认同消耗更多蛋白质可以降低食欲的观点。哈佛大学公共健康学院(Harvard School of Public Health)的萨克斯(Frank Sacks)领导了一项研究，其论文刊登在《新英格兰医学期刊》(New England Journal of Medicine)上。这项研究对参加四组节食疗法的811名成年肥胖者进行比较，每组所采用的节食疗法蛋白质、脂肪和碳水化合物含量各不相同。他说，我们发现他们的饱足和饥饿程度没有任何区别。

参加研究的四组患者减去了类似的体重，其他减肥专家说，这并不令人吃惊，因为他们的脂肪、蛋白质和碳水化合物摄入量只有细微的差别，而且很多参与者并没有坚持减肥计划。

当然，如果你像亚隆建议的那样进食，总的来说你就会摄入较少的热量。关键是，在每天早间食用蛋白质或许会比较容易减少热量摄入。