So understand that when you eat a “normal” meal of a hamburger and french fries with a vanilla shake, that is approximately 98 carbs and 20 grams of protein. And if you just go back to work and sit in front of a computer or just walk around your building doing light lifting, you will not use (metabolize) all those carbs and proteins (which break down into sugar). Which will cause your insulin the burden of trying to push all those unused sugars (carbs/proteins) into your already drenched with sugar soak cells. This is what gives rise to insulin resistance which gives you a fatty liver and more insulin resistance until you finally get a fatty pancreas and a fatty you with type 2 diabetes!
Fun Fact: a corollary on how to make a fatty liver is like making foie gras. To produce “foie gras” (the French term means “fatty liver”), workers ram pipes down the throats of caged (no exercise) male ducks twice each day, pumping up to 2.2 pounds of grains (starchy carbs/sugars) making their livers extremely fat.