In the modern world you are rarely hungry, yet you can almost always be seduced into eating.

You naturally eat when food is available. Since food is almost always available for us, it’s not surprising people prone to obesity are overweight.

Why would you be built to eat when food becomes available? Survival. In humanity’s past, food supplies were scarce and unpredictable, so humans needed to eat all the food they could when food became available. Any excess calories are stored as precious fat reserves for use later. Not eating would be foolish and potentially deadly.

Why would you have this incredible ability to store near unlimited amounts of fat if you didn’t also have the ability to overeat? If you couldn’t eat more when you were full, there would be very little chance of you eating enough to store excess calories as fat.

Many studies show that you will eat when food becomes available, even if you think you are full, even after a big meal. And when a food tastes good, you will naturally keep on eating, even when full.

Another piece of evidence can be found in how often you eat. Do you ever go long without eating? Probably not. Do you think you only eat when you are really hungry or when you really need energy? It’s unlikely. You probably eat on a fairly regular schedule even when you don’t need the energy and there’s no reason for you to be hungry. So you already know you can eat a lot of food when you don’t need to.

Even stranger, you will eat even when you are overweight and don’t need any additional weight. And stranger still, you will eat when you desperately don’t want to eat more. How can this be?

Passing up available food doesn’t make sense from a survival perspective. For most of human history, humans did not have a way to store food. There was no refrigerator or grocery store.

Your natural food storage mechanism is to eat and store the excess as fat. Later, when food is scarce, the fat is used for energy and survival. As there was rarely too much food, obesity wasn’t a problem. Preventing you from becoming too fat was never a capability the human body had to develop.

When I put it this way, can you imagine your body not having a way to make you eat when food becomes available? It makes no sense to think otherwise.

The end result is you eat when food is available and because food is always available you can eat all the time. This is one role the environment plays in obesity. If the environment didn’t have an endless supply of food, then you couldn’t eat it and you couldn’t become overweight.