研究发现，每周禁食 2 天可以帮助肥胖者适当减轻体重

The 5:2 diet, a type of intermittent fasting, is no more effective than traditional approaches to weight loss, according to what researchers said was the first study of the regimen in a "real-life setting."

However, the researchers found that the approach, which involves two days of heavily restricting calories (500 calories for women, 600 calories for men) and five days of sensible eating, was rated more highly by the obese people in the study because it was easy to follow.

"Here we've been able to provide the first results on the effectiveness of simple 5:2 diet advice in a real-life setting. We found that although the 5:2 diet wasn't superior to traditional approaches in terms of weight loss, users preferred this approach as it was simpler and more attractive," said Katie Myers Smith, a chartered health psychologist and senior research fellow at Queen Mary University of London, in a news statement. She was an author of the study that published in the scientific journal PLOS ONE.

Doctors may want to consider including the 5:2 diet as part of their standard weight management advice to patients, she said.

The study involved 300 obese people in Tower Hamlets, an inner city area of high deprivation in London. The participants either followed the 5:2 regimen or a more conventional approach to losing weight that stressed eating more vegetables and whole-grain foods, cutting out foods high in sugar and fat, eating smaller portions and exercise.

'Modest' results

The results of both approaches were very similar and "modest," the study said.

At six months, those using the 5:2 diet had lost, on average, 1.8 kilograms (4 pounds) compared to 1.7 kilograms (3.7 pounds) on the standard diet advice. At 12 months, those figures were 1.9 kilograms (4.2 pounds) and 1.8 kilograms (4 pounds), respectively.

Some 18% of 5:2 dieters had lost at least 5% of their body weight after one year compared to 15% using the conventional approach.

Of the group following the 5:2 diet, half attended six group support sessions for the first six weeks after the initial information session. However, its impact of the group support diminished over time, the study found.

Participants were positive about the different weight loss approaches, but those on the 5:2 diet were more likely to recommend it to others and said they were more likely to continue with the approach.

The study was a randomized control trial, regarded as the most rigorous kind of research, and while the number of participants was larger than most previous studies of intermittent fasting, the authors said "some findings of borderline significance could have become clearer if the sample size was larger."

The people following the conventional weight loss guidance were also more likely to try other strategies such as Weight Watchers, Slimming World or other diets. This factor could have masked the effects, but it would not have been ethical or practical to stop participants trying alternative approaches, the study authors said.

Intermittent fasting

Some experts think that alternating between fasting and eating can improve cellular health by triggering metabolic switching.

In metabolic switching, cells use up their fuel stores and convert fat to energy -- "flipping a switch" from fat storing to fat saving.

Intermittent fasting can reduce blood pressure, aid in weight loss, and improve longevity, a review of past animal and human studies published in The New England Journal of Medicine suggests.

The method is not appropriate for everyone, however, particularly pregnant women and those with medical conditions such as diabetes or eating disorders.

研究发现，每周禁食 2 天可以帮助肥胖者适当减轻体重

根据研究人员所说，5:2 饮食是一种间歇性禁食，并不比传统的减肥方法更有效，这是在“现实生活环境”中对该方案的第一项研究。

然而，研究人员发现，这种包括两天严格限制卡路里摄入（女性为 500 卡路里，男性为 600 卡路里）和五天合理饮食的方法，在研究中被肥胖者评为更高，因为它很容易遵从。

“在这里，我们已经能够在现实生活中提供关于简单 5:2 饮食建议有效性的第一个结果。我们发现，尽管 5:2 饮食在减肥方面并不优于传统方法，用户更喜欢这种方法，因为它更简单、更有吸引力，”伦敦玛丽女王大学特许健康心理学家和高级研究员凯蒂迈尔斯史密斯在一份新闻声明中说。她是发表在科学期刊 PLOS ONE 上的研究的作者。

她说，医生可能会考虑将 5:2 饮食作为他们对患者的标准体重管理建议的一部分。

该研究涉及伦敦塔哈姆雷特 (Tower Hamlets) 的 300 名肥胖者，这是伦敦一个高度贫困的内城区。参与者要么遵循 5:2 方案，要么采用更传统的减肥方法，即强调多吃蔬菜和全麦食品，少吃高糖和高脂肪的食物，少食多餐和锻炼。

“适度”的结果

研究称，这两种方法的结果非常相似且“适度”。

在六个月时，使用 5:2 饮食的人平均减掉了 1.8 公斤（4 磅），而标准饮食建议的减重 1.7 公斤（3.7 磅）。在 12 个月时，这些数字分别为 1.9 公斤（4.2 磅）和 1.8 公斤（4 磅）。

大约 18% 的 5:2 节食者在一年后减掉了至少 5% 的体重，而使用传统方法的这一比例为 15%。

在遵循 5:2 饮食的组中，一半参加了初始信息会议后前六周的六次小组支持会议。然而，研究发现，随着时间的推移，它对团体支持的影响逐渐减弱。

参与者对不同的减肥方法持积极态度，但那些采用 5:2 饮食的人更有可能向其他人推荐这种方法，并表示他们更有可能继续采用这种方法。

该研究是一项随机对照试验，被认为是最严格的研究类型，虽然参与者的数量比之前大多数间歇性禁食的研究要多，但作者表示，“如果样本量足够大，一些具有临界意义的发现可能会变得更加清晰。更大。”

遵循传统减肥指南的人也更有可能尝试其他策略，例如 Weight Watchers、Slimming World 或其他饮食。研究作者说，这个因素可能掩盖了影响，但阻止参与者尝试其他方法是不道德或不切实际的。

间歇性禁食

一些专家认为，交替禁食和进食可以通过触发代谢转换来改善细胞健康。

在代谢转换中，细胞耗尽了它们的燃料储存并将脂肪转化为能量——从脂肪储存到脂肪储存“翻转开关”。

发表在《新英格兰医学杂志》上的一项对过去动物和人类研究的回顾表明，间歇性禁食可以降低血压、帮助减轻体重并延长寿命。

然而，这种方法并不适合所有人，尤其是孕妇和患有糖尿病或饮食失调等疾病的人。