今天讀一篇《新科學(xué)家》(new scientist) 雜志上的文章。

關(guān)于肥胖的話題，有很多似乎成為定律的說法：

1. 肥胖是因?yàn)槌缘倪^多

2. 少吃多動(dòng)能甩掉肥肉

3. 燃燒卡路里=瘦身

然而，就美國民眾而言，2021 年美國人比 2020年更胖了。

居家辦公，應(yīng)該運(yùn)動(dòng)更為便利。為什么人們更胖了呢？

我們一起來讀讀這篇文章，作者會(huì)告訴你：多吃高脂肪反而會(huì)減緩肥胖癥狀。

很意外，對(duì)不對(duì)？

IN PRINCIPLE, it sounds simple: eat less and move more. This dietary advice for tackling obesity has been around for decades. Yet, despite all the calorie counting, dieting and exercising, worldwide obesity rates just keep ticking up.

People in the US, for example, were heavier in2021 than they were in 2020, placing many more people at risk from diabetes and other serious chronic diseases. So why hasn’t this approach to weight control worked?

One possibility is that we haven’t tried hard enough. Perhaps we have lacked the discipline and willpower to maintain healthy dietary and exercise habits – a challenge made more difficult today for those surrounded by inexpensive, tasty, highly processed foods.

Or perhaps the problem is the focus on “calorie balance” itself. In a recent paper, my colleagues and I question the basic assumption of whether taking in more calories than you burn really is the primary cause of obesity. We argue that the evidence actually points the other way: we are driven to overeat because we are getting fatter (The American Journal of Clinical Nutrition, doi.org/gmtn3z).

This may seem incredible, but consider the adolescent growth spurt. As their growth rate speeds up, teenagers may eat hundreds of calories more each day than they used to. Does this “overeating” cause the rapid growth? Or does the rapid growth, which requires more calories to build new body tissues, make teens hungrier so they eat more? Clearly the latter, as adults won’t grow taller, no matter how much they eat.

The key to how this works in obesity is hormones, especially the fat-storage hormone insulin (胰島素). Processed, rapidly digestible carbohydrates (碳水化合物) – foods like sweetened breakfast cereals, potato chips and sugarybeverages – raise our insulin level too high. This causes our fat cells to take in and store too many calories, leaving fewer available for the rest of the body. A few hours after eating a high-carb（碳水化合物）meal, the number of calories in the blood stream plummets, so we get hungrier sooner after eating.

Consider another example: oedema（水腫）, in which excess fluid builds up in body tissues, such as thelegs. People with oedema tend to become thirsty, despite the excess, because the fluid doesn’t stay in the blood where it is needed. From this perspective,the difficulty resisting hunger that so many dieters have isn’t a sign of poor discipline, but rather a biological problem involving how our bodies distribute the calories we consume.

The two opposing views of cause and effect in obesity have radically different implications for how to prevent and treat weight problems. Whereas the usual approach focuses on how much to eat, with prescriptions for daily calorie intake, in ourview, the emphasis should be placed on what to eat.

Replacing processed carbs with high-fat foods – such as nuts, full-fat dairy, olive oil, avocado and dark chocolate – lowers insulin levels, making more calories from the meal available for the rest of the body. Counter-intuitively, higher-fat foods may help shed body fat, a possibility supported by clinical trials comparing high-fat diets with low-fat ones.

This way of thinking might help explain why calorie restriction usually fails long before a person with obesity approaches an ideal bodyweight. A low-calorie, low-fat diet further restricts an already limited supply of energy to the body, exacerbating hunger without addressing the underlying predisposition to store too many calories in body fat. Consequently, weight loss becomes a battle between mind and metabolism that most people will probably lose.

Although much more research will be needed to test this provocative idea, it is timeto question the basic assumptions about cause and effect, calories and weight gain that have dominated our thinking for decades.

整篇文章600詞左右，難度中等，生詞基本沒有。只有幾個(gè)專業(yè)術(shù)語：胰島素和碳水化合物。

這也是各種英語閱讀理解中會(huì)考察的題材：科普知識(shí)。有些內(nèi)容不難，但有時(shí)卻讀不懂。

所以，一定要把文章的邏輯關(guān)系找出來，找到關(guān)鍵句子。

文章最后，作者寫道：是時(shí)候重新思考卡路里與體重增加之間的因果關(guān)系了！

如果你也在減肥，不妨試一試作者的建議：遵循身體的運(yùn)行機(jī)理，少吃碳水化合物的食物，多吃點(diǎn)高脂肪食物。