限时饮食越来越受欢迎，但它健康吗?

Tipping the scales at 233 pounds, Charles Joy realized he needed to make some changes.

28岁的路易斯维尔, Kentucky, native already had tried many diet plans to varying degrees of success. 2013年，他通过锻炼和节食减掉了100多磅. 但后来，他的体重开始慢慢回升.

In 2017, 乔伊决定尝试限时饮食, 每天在8到10小时内吃完所有的饭. 磅融化了。. 如今，他的体重是183磅.

乔伊说:“它工作起来好多了，因为它非常灵活。. "With calorie restriction, you have to plan out everything, and I was never satisfied. 现在我直到下午才想到吃的."

Time-restricted eating is one variation of a hot diet trend that also includes intermittent fasting. 据克里斯塔·瓦拉迪所说, an associate professor of nutrition at the University of Illinois at Chicago, 间歇性禁食有几种类型, 包括每天一餐, the 5/2 method, 其中包括5天的盛宴和2天的卡路里限制, 隔日禁食.

禁食并不是什么新鲜事. 每年一个月, practicing Muslims celebrate Ramadan by fasting from sunrise to sunset, 它也是许多其他主要宗教传统的一部分. But is it healthy and effective to restrict eating or fast on a regular basis?

It can be, said Varady, who said she has run more than a dozen clinical trials on alternate-day fasting and one on time-restricted eating.

In a 2017 美国医学会内科杂志 trial, Varady and her colleagues showed alternate-day fasting was just as effective as daily calorie restriction for losing weight and maintaining the loss.

“通过隔日禁食, people typically lose 3 to 8 percent of their body weight over three to 12 months," Varady said. 它对低脂和高脂饮食都有效.

减肥并不是唯一的好处. In a 2009 study, most of the study participants also saw reductions in the so-called "bad" LDL cholesterol and in blood pressure. 其他研究表明胰岛素抵抗会降低, 会增加患2型糖尿病的风险. 糖尿病是心脏病的一个危险因素.

Alternate-day fasting works, at least in part, because people wind up consuming less food overall.

But those who use time-restricted eating can lose weight without restricting caloric intake, said Dr. Satchidananda熊猫, a professor and researcher at the Salk Institute for Biological Studies in La Jolla, California. 他还写了一本关于限时饮食的书.

"The science and the benefits of time-restricted eating are very different from those of other forms of fasting," Panda said.

据熊猫说, 限时饮食是基于昼夜节律的科学, 它们控制着每一种激素.

In a 2012 study潘达和他的团队将老鼠分成两组. One ate all the sugary, fatty foods they wanted during a 24-hour period. The other group had the same sorts of foods but were only allowed to eat during an eight-hour daily window. 两组人摄入的卡路里数相同, but the mice that ate round-the-clock became fat and sick while those on a time-restricted diet did not.

Panda also has shown that fruit flies placed on a time-restricted eating plan have hearts that appear to be 20 to 30 percent younger than their age would suggest. 果蝇的心脏和人类的心脏是相似的, so Panda believes it's reasonable to conclude humans might benefit in the same way.

"It works by slightly reducing ATP producing proteins of mitochondria in the heart and keeping the mitochondria healthy, 可以减少氧化应激," Panda said, noting that time-restricted eating gives the body time to repair itself. "Most of our studies are showing that the effect is on multiple organs and on the central nervous system. 这是一个正反馈循环."

潘达希望继续他的研究, and find out whether the health benefits seen in animal studies hold true for humans. Data collected from his smartphone app, myCircadianClock, could be key. The app helps people track when they eat, sleep, exercise and take supplements and medications.

"We send them push notifications asking them what improvement they are seeing," Panda said.

在Panda的大多数研究中，人们在8点到8点之间吃第一顿饭.m. and 10 a.m. 但查尔斯·乔伊通常等到下午4点.m. 开斋. 乔伊的医生最初对这种饮食很担心, but Joy felt vindicated by his low cholesterol and blood pressure readings. 他短期内没有改变现状的计划.

“我一生都很肥胖，而且非常不健康, 他是学校里块头最大的," Joy said. “这感觉很棒，我想尽可能地保持下去."