Going without food for several hours can sometimes feel like an impossible task. But how would you feel if you had to go days without any significant source of calories? It is a question asked by people interested in fasting, as well as those planning for an emergency.
小费
没有食物你可以生存de的天数pends on several factors, including your current body weight, activity level, overall health and age.
How Long Without Food?
当你严格限制卡路里或停止进食的一定时间，你的身体会认为它进入饥荒。当发生这种情况时，营养和饮食学院解释说，你的身体需要做更多，更少的热量。随着时间的推移，你的身体会适应这种限制热量的摄入，因此，使用更少的热量来执行相同的任务。这不是任何人的好消息想减肥和保持它关闭长远。
此外，UCLA Center for Human Nutrition说，每天吃少于1000个卡路里的效果相同的生理。他们接着说，经过四五天，你的食欲会降低，并且在大多数情况下，你将不再是饿了。
Defining an exact number of days you can survive without food is next to impossible. In fact, there are no current scientific studies or research that explore this topic in-depth. However, an older study that looked at starvation points to a range of days.
A November-December 2009 review published in档案馆皮草Kriminologie分析被困或活埋后不久人们如何生存。通过从大众媒体和其它输入报道，研究人员发现，似乎有可能没有食物和饮料存活八至21天。但是，如果你只是剥夺了食物，这个范围可以去了。
阅读更多：一天是多少卡路里考虑饿肚子？
水化的重要性
天的确切数量，你可以去没有食物取决于多种因素，比如你的年龄，活动量，目前体重和其他健康问题。正因为如此，专家们更多地谈论了一系列的天，这可以从一个小东西在一个星期至一个月以上。
But when it comes to hydration, the range gets narrowed down a bit, and the number of days is far less than the number of days you can survive without food. Just like the number of days without food, determining the exact number of days you can survive without water is not an exact science and it depends on many factors. That said, once dehydration sets in, you may only have a matter of days before the effects of no water become grim and dangerous.
Dehydration is a real concern for athletes, anyone living in hot climates or in ill health. The疾病预防与控制中心说，水可以帮助你的身体控制其温度，润滑和缓冲关节，保护脊髓，并通过汗液，尿液和大便的时刻清除体内垃圾。该Mayo Clinic援引脱水的几种症状，包括极度口渴，少尿频，深色尿，乏力，头晕和混乱。
阅读更多：我如何才能知道我的身体水合？
卡路里数量优化
该re are several reasons people eliminate food for a set period of time, including,fasts for personal，spiritual or religious reasons, medical procedures and weight loss. If you choose to fast, for whatever reason, it's a good idea to follow a prescribed plan from an expert such as a registered dietitian or medical doctor, or work with your physician so they can监测任何副作用。
但是，如果你正在寻找保持最佳的健康状态，你可以使用膳食指南美国人as a place to start. According to the guidelines' calculations, a sedentary male between the ages of 26 and 40 needs 2,400 calories per day, and an active male aged 26 to 40 needs 2,600 calories. A sedentary female between the ages of 26 and 50 needs 1,800 calories per day, and an active female aged 26 to 50 needs 2,000 calories.
To provide your body with quality calories and nutrients,follow a diet即在水果，蔬菜，瘦蛋白，复合碳水化合物和健康的脂肪，同时减少饱和脂肪和反式，加入糖，盐和加工的食品的量高时，根据哈佛T.H.公共卫生禅宗。
- 档案馆皮草Kriminologie：“生存时间没有食物和饮料”
- 营养和饮食学院：“4代谢神话与真相”
- UCLA Center for Human Nutrition: "Very Low Calorie Diet VLCD"
- 美国疾病控制和预防中心：“水和营养”
- 梅奥诊所：“脱水：症状和原因”
- U.S. Department of Health and Human Services: "Dietary Guidelines for Americans, 2015-2020: Appendix 2. Estimated Calorie Needs per Day, by Age, Sex, and Physical Activity Level"
- 哈佛T.H.陈公共卫生学院：“健康饮食板”
- 健康和人类服务的美国能源部：“膳食指南的美国人”