You already know what will eventually happen if you permanently stop eating. But between that last morsel of food and your final breath, there are a lot of biochemical processes that take place in your body.
They're all laid out in a new video below in the accessible, illustrative style for which YouTube channel AsapScience has become known. On one hand, it's frightening to see just how quickly things can go downhill as our body desperately turns to every possible source of energy we carry on our frame in an effort to survive. On the other, as the video says, "it's incredible that the body can sustain for so long without food."
The video bookends your food-less time on Earth between three weeks to 70 days and notes that survival time is largely dependent on how much water you have access to and the fat reserves you carry on your body.
Of course, for millions of people around the world, access to food, clean water and an excess of body fat is severely limited. That's why at the end of the video, the good folks at AsapScience ask you to hold accountable the seven richest countries (the G7) to make good on their pledge to raise 500 million people out of hunger and malnutrition by 2030 (you can see their pledge on page 19 of this PDF) by either sharing the video or going to the Global Citizen website.
Global Citizen is an organization that calls attention to and advocates to end harmful living conditions around the world. The group will host its "2015 Global Citizen Festival" in Central Park in New York on September 26 with performances by Ed Sheeran, Pearl Jam, Beyoncé and Coldplay. You can have a chance to win tickets by participating in various "get the word out" campaigns through the site.
For now be glad that this probably won't be happening to you anytime soon.