Actually, it’s not that we’re hungry all the time. it’s that we don’t know how to listen to our hunger signals. We eat shortly after we wake up not necessarily because we’re hungry yet, but because we’re told breakfast is the most important meal of the day, and because we can’t eat a proper breakfast meal at work, and we know we can’t wait until lunchtime to eat, so we don’t have a choice. We eat at a specific lunch “time” because that’s when we’re permitted to leave work (or when school permits us to) and it doesn’t matter if we’re not really hungry after a good breakfast or if we’re overly hungry because we skipped breakfast or its been too long since. We eat dinner when we can after a long day of work, then snack at night because we can, it’s our only unrestricted time to eat. And because at least the first two, if not all three of our meals are eating during a time crunch, we jam our food in, not waiting between bites, not giving our brains time to process our satiation and give us the signal “that’s enough!”
For a detailed explanation of where Earth's water is, look at the data table below. Notice how of the world's total water supply of about million mi 3 of water, over 96 percent is saline. Of total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Rivers are the source of most of the fresh surface water people use, but they only constitute about 300 mi 3 (1,250 km 3 ), about 1/10,000 th of one percent of total water.
Note: Percentages may not sum to 100 percent due to rounding.