Processed carbohydrates like starch and simple sugars negatively impact blood glucose levels, causing many people to feel better when cutting them.

“My guess is... This is my theory to be tested, that people feel better cutting carbohydrates out, because the diet that we eat in the United States and in industrialized countries, the carbohydrates are largely crap. - Processed. - It's like starch, simple sugar. It's things that contribute to glycemic index. It's these sugars that we eat. They make it to our small intestine, they get chopped up into simple sugars, absorbed into our bloodstream, and we have a ton of glucose then coursing through our veins, which we know is bad and can lead to things like diabetes.”