Cooking was our first foray into the world of food processing. It unlocked extra calories from food sources and some argue paved the way for the evolution of our bigger brains. Fast forward to the modern day however and food processing has been taken to a rather more deleterious extreme.
Like cooking, modern food processing increases the calorie availability of food which means a greater percentage of processed food calories end up in our body. It is like a form of pre-digestion breaking down complex foods into easily-absorbed energy. Sugar, refined carbs and oils (the staple ingredients in most packaged foods) are the primary culprits. This is one of several reasons why weight gain is so much easier and more common on a highly processed diet.
As ever the solution is to switch to a primarily whole-foods based diet where the calories are typically less readily available and require more work from our digestive system to access (even after cooking.) Coupled with a higher nutrient density and greater appetite regulating qualities and its easy to see why switching to whole-foods can be so beneficial for our waistlines and wellbeing.