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How Long Can You Survive Without Food?

How long can you survive without food? Generally speaking, most adults can survive around a month without food, with known exceptions lasting over 2 months. Children usually can only survive for a few days to a few weeks. However, these are only rough estimates. There is no drop-dead answer to this (pun intended), as your actual survival time will depend on several factors like your age, weight, and activity level.

Additionally, testing the matter in scientific studies is deemed altogether unethical.

But join us as we explore how long a person can realistically go without food and water, as well as other just-in-case practices to stay safe while recreating outdoors.

How Long Can a Human Survive Without Food?

Survival without food also drastically depends on your access to water. If you don’t have water, the lack of food generally won’t matter. The average person can only go about three to five days without water versus about a month without food. However, many factors affect how long someone can survive without water, such as age, health, climate, and activity level.

Other factors that determine your timeline to starvation include:

  • Your environmental situation: If the climate is hot and dry vs. cold and damp, it’ll be different as well.
  • Your activity level: If you’re very active, you’ll burn more calories and may need to eat more often to maintain your energy levels.
  • Illness or injury: if you are ill or injured, your body will require additional calories to heal.
  • If you’re pregnant or breastfeeding: you’ll need to eat more frequently to stay healthy.

The bottom line is that it’s not very long, and the detrimental effects of starvation start kicking in long before you kick the bucket.

How Long Can You Go Without Eating

The Effects of Starvation on the Body

If you’ve ever watched a survival TV show, you’ve probably seen the effects of starvation on the contestants. They start complaining about hunger almost immediately, however, most realize that other survival tasks must be completed first. Shelter and water are most important at the beginning from a survival standpoint. Regardless, changes in your body start within the first 24 hours without food.

Here’s a look at the possible effects of starvation on the human body after one day, two to three days, and four days or more.

After 1 Day

After one or two days of not eating, there are already some noticeable effects on the body. Most people switch from glycolysis (burning glucose) to ketosis (burning ketones from fat reserves). During the switch, the person will feel weak and tired, their skin will be dry, and they will have difficulty concentrating. They may also experience dizziness and headaches.

Male survivalist camper sitting by fire.
People can go weeks without eating, but after a few days, the effects will start to present themselves.

2 Days to a Week

After two to three days of not eating, the brain will start screaming for glucose to keep from shutting down. To get it the human body will start to break down muscle tissue and other protein sources to get energy. This will lead to even more fatigue and muscle atrophy, as well as cramps and diarrhea.

The person’s heart rate and blood pressure will drop. They may feel lightheaded and start to experience hallucinations, walking may become difficult, and they may even fall into a coma.

After A Week

After about a week without food, the breakdown of proteins will continue to fatigue and damage organs. In addition, the lack of necessary vitamins and minerals will weaken the immune system making the body susceptible to infection.

If an illness or infection does not set in, organs eventually fail and the body will shut down.

group of friends lost in the woods
After one or two days of not eating, there are already some noticeable effects on the body.

Health Complications From Lack of Food

It’s surprising just how long some people can survive without it. Some people can survive for weeks, but it’s important to note that the quality of life will be very poor during this time.

Without adequate nutrition, the body begins to break down muscle tissue for energy, leading to weakness and fatigue. In addition, the digestive system slows down, and people may experience constipation, diarrhea, and vomiting. The latter two do not help when one is trying to stay hydrated for survival.

Over a surprisingly short period of time, these health complications can become life-threatening. Malnutrition can cause desperately low blood sugar levels, organ failure, and even death. So, while it is technically possible to go without food for an extended period, it will not be fun.

Empty plate with clock on it
Without proper nutrition, the human body will start to break down muscles and become weak and fatigued.

How Long Can You Live Without Water?

While Mahatma Ganda once went 21 days without food and only minimal sips of water, the longest anyone is known to have gone without water and survived is 18 days. However, as a general rule, most people can survive for about three days without water.

Factors that affect fatal dehydration include:

  • age
  • health
  • climate
  • activity level.

For example, a young, healthy person in a cool climate can survive without water for much longer than an older person in a hot climate. Furthermore, someone who’s sedentary will need less water than someone active.

The bottom line is that everyone’s hydration needs are different, and how long you can survive without water will depend on your individual circumstances.

If you find yourself in a situation where you don’t have access to clean water, it’s important to ration your intake and make sure you’re drinking enough to stay hydrated as best you can while maintaining your water supply.

Pro Tip: Always have an emergency food stash on hand in your bug-out bag. Find out what else you should pack in your emergency bag.

If lost in the wilderness, you’ll likely dehydrate before you succumb to starvation.

Is Fasting Safe for the Human Body?

The human body can go without food for a short period without terrible effects. In fact, fasting has been shown to have some health benefits, including improved digestion, increased energy levels, and reduced inflammation.

However, it’s important to understand the difference between fasting and starvation. Fasting is a voluntary decision to go without food, while starvation is involuntary deprivation. Fasting can be and should be stopped if any red flags appear. As we noted, starvation can lead to serious health problems.

Short-term fasts (up to 24 hours) without eating are generally considered safe for most people. However, longer fasts (more than 24 hours) should only be under medical supervision. This is because they can lead to dehydration and electrolyte imbalances. We’ve dabbled in the fasting game before, usually opting for the occasional 15-18 hour fasts to get a good reset, but replenish with plenty of electrolytes and nutrients afterward.

When done correctly, fasting can be a safe and healthy way to improve your overall health. Just be sure to talk to your doctor before starting any fasting regimen, and make sure you’re well-informed about the risks and benefits.

How Many Calories Is Starving Yourself?

Unfortunately, it is possible to starve yourself even when eating food. While we may technically survive for longer than if we didn’t have any food, a low-calorie diet will still put our bodies into “starvation mode” and lead to harmful effects on our bodies.

A diet of 1,000-1,200 calories is the bare minimum our bodies require, and anything below this is considered by many to be a starvation diet.

Contrary to what you may think, a starvation diet can actually be counterproductive to weight loss and is very unhealthy for your brain, muscles, and organs. While yes, you will see weight loss on the scale, starvation mode lowers your metabolism which makes burning calories harder when you do eat. You will also experience adverse side effects that will make you miserable. If weight loss is your goal, we highly recommend finding another plan of action for a sustainable lifestyle change.

How Long Can a Person Survive Without Water?

Create a Stash of Emergency Food & Water

Now that you know how long you can go without food and water, it’s time to start creating your stash of emergency food. Even if you’re just a casual day-hiker, having emergency food and water handy will keep you prepared for the unexpected. This is especially a great idea if you’re adventuring in the backcountry or thru-hiking long remote trails that don’t see as much traffic. We always pack an emergency food supply when we go hiking, just in case.

Make sure to include a variety of foods that will last longer and are easy to prepare. Canned foods are a good choice for your stationary emergency stash, but are heavy to carry regularly on a hiking trip. We recommend things like granola bars, freeze-dried foods, dry foods that last a long time such as ready-to-eat meals, and multivitamins. These are lightweight and can get packed once and forgotten about for a few outings.

Of course, don’t forget about clean drinking water, which you can round out with electrolyte-containing sports drinks and powdered milk. Emergency water purification tablets are great to have on any trip. We bring tablets and emergency water filters with us on every national park exploration.

Whether you make a wrong turn, are out longer than you think, or a natural disaster strikes, you’ll be glad you have everything you need to stay fed and watered. There’s no need to test yourself on how long you can go without food.

Was there ever a time you had to go without food? Tell us your experience in the comments!

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About Cait Morton

Co-Founder, Logistics Queen, Business & Content Manager, and Animal Lover

An Upper Peninsula of Michigan native (aka a Yooper), Caitlin is the organization, big-picture, and content strategy queen of our operation. She keeps everything orderly and on track.

With a background in Business Management, she supports and helps channel Tom’s technical prowess into the helpful content our readers and viewers expect. That’s not to say you won’t find her turning wrenches and talking shop – RV life is a team effort. She keeps the business and the blog moving forward with a variety of topics and resources for our audience.

Believe it or not, she is rather camera shy, though she co-hosts the Mortons’ personal videos and The RVers TV show.

Caitlin’s passion lies in outdoor recreation and with animals. Some of her favorite things to do are hiking, biking, and getting out on the water via kayak, SUP, or boat.

She also loves the RV life due to the fact that you can bring your pets along. Sharing information about safely recreating outdoors with your whole family – pets included! – is very important to her. Because of this, Caitlin spearheaded the launch of HypePets in 2023.

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