负卡路里？别做梦了

饮食处处有，但是吃“负卡路里”食物，比如芹菜和葡萄柚，能帮你减肥吗?

A calorie is a unit of energy, usually expressed as kilocalories (kcal) for the energy content in food. The theory behind negative calorie foods is that some foods have lower calorie (energy) content than the amount of energy it takes to digest and absorb the food into the body. This sounds plausible, in theory. But in reality, even the lowest calorie foods, such as celery, contain more calories than it takes to break down and absorb them in the body.

负卡路里一般是指消耗该食物所需的卡路里比食物本身提供的卡路里要更多。从理论上讲，这听起来似乎有道理，但在现实生活中，即使是最少卡路里的食物，比如芹菜，也是包含比消耗自身所需更多卡路里的。

Our energy needs are made up of three components:

我们的能量需求由三个部分组成：

• The energy needed to maintain a body at rest, which is the energy needed for our body to carry out its basic processes so we can live.

· 维持身体静止所需的能量，这是我们身体执行基本代谢所需的能量，因此我们可以活着.

• The thermic effect of eating, which is the increase in metabolic rate after eating, while food is digested and absorbed.

· 进食的热效应，即进食后代谢率的增加，同时食物被消化吸收.

• Additional energy needed for activity and exercise.

· 活动和锻炼所需的额外能量.

Of these, the thermic effect uses the fewest calories—about 10% of the energy we take in. In other words, about a tenth of the calories we eat are used to process our food—this includes chewing our food, moving it through the digestive system, absorbing nutrients, and storing excess energy.

其中，进食热效应消耗最少的卡路里 - 约占我们摄入的能量的10%。换句话说，我们吃的卡路里大约十分之一用于处理我们的食物 - 这包括咀嚼我们的食物，将其移动通过消化系统，吸收营养，储存多余的能量。

Foods such as celery, grapefruit, broccoli, tomatoes, and cucumber have all been touted as negative calorie foods, but there is no scientific evidence to support this idea. Although they are very low calorie foods, with seven to 30 kcal per 100g, it still takes less energy than this to process them. This is because they contain large amounts of water and fiber, which have a very low energy cost.

芹菜、葡萄柚、西兰花、西红柿和黄瓜等食品都被吹捧为负卡路里食品，但没有科学证据支持这一观点虽然它们是非常低卡路里的食物，每100克含有7到30千卡热量，但它仍然需要比这更少的能量来处理自身。这是因为它们含有大量的水和纤维，其能量成本非常低。

Replace, don’t add

换着吃，别多吃

These foods are very useful for people who are trying to lose weight, as they contain a low number of calories. By replacing the food in your diet with some of these—for example, replacing a side portion of chips with a side salad—it is possible to lower your calorie intake considerably. As an extra boost, they are full of nutrients, such as vitamins and minerals, and also contain a lot of fiber, which also has many benefitsfor your health.

这些食物对于试图减肥的人非常有用，因为它们含有少量的卡路里。通过用这些食物代替原来吃的食物 - 例如，用配菜沙拉替换配菜薯片 - 可以大大降低你的卡路里摄入量。作为额外的助力，它们富含营养素，如维生素和矿物质，还含有大量纤维，这对健康也有很多好处。

It’s important to replace higher calorie items on a plate rather than add these fruit and vegetables to meals, as by simply adding healthy items you increase the overall calorie content. For example, a cheeseburger plus a salad contains more calories than a cheeseburger alone.

重要的是把食物中更高卡路里的部分换成更低的，而不是将这些水果和蔬菜添加到膳食中，因为简单地添加健康食品还是会增加总体卡路里含量。例如，芝士汉堡和沙拉比单独的芝士汉堡含有更多的卡路里。

In order to lose weight, people need to use up more energy than the energy (calories) they eat and drink, but this is difficult. Research has shown that people tend to underestimate the calorie content of the food they consume, and they underestimate it by more if they are obese rather than normal weight.

为了减肥，人们需要消耗的能量超过他们摄入的能量，但这很难。研究表明，人们倾向于低估他们摄入的食物的卡路里含量，如果他们越肥胖就越会低估。

Researchers have also shown that when people visit fast food chains with a healthier image, they underestimate the calorie content of their meals compared with the same meals at a restaurant with a less healthy image, and may end up consuming more calories overall.

研究人员还表明，当人们去具有更健康形象的快餐连锁店时，与低于健康形象的餐厅的同餐相比，他们更低估了他们的膳食中的卡路里含量，并且可能最终消耗更多的卡路里。

Another difficulty is keeping weight off in the long run. Many studies have shown the short-term benefits of diets to help with weight loss, but over 80% of people put the weight back on again over time. In many modern societies, there is easy access to cheap high-calorie foods, so it is difficult to resist high fat/sugar options on a permanent basis.

另一个困难是长期保持体重。许多研究表明饮食有助于减轻体重的短期益处，但超过80%的人会随着时间的推移重新恢复体重。在现代社会中，很容易获得廉价的高热量食物，因此很难长期抵制高脂肪/糖的饮食选择。

Unfortunately, negative calorie foods are a myth, and there is no easy way to lose weight and keep it off in the long run. Changing your food and drink options for healthier ones on a permanent basis is more likely to lead to sustained long-term weight loss than short-term dieting alone.

不幸的是，负卡路里食物是唬人的，从长远来看，没有简单的减肥方法。长期替换健康食物和饮料的选择比单独短期节食更有可能帮助持续的长期减重。