Sugar From Grains
It comes from a grain, which contains antinutrients and lots of carbs (which is how they make it into sugar). Sugar is bad because it creates a spike in blood sugar, leading to a crash a couple hours later, which results in an energy slump and a craving for more sugar to get your blood sugar back up.
Paleo and Insulin Management
When blood sugar rises, the body produces insulin to digest all the sugar. Insulin promotes the storage of nutrients as fat and prevents the breakdown of fat for energy. It’s a nifty hormone that we need to survive, but chronically high levels of insulin lead to insulin resistance: when the cells become desensitized to insulin and stop accepting it, requiring the pancreas to produce more insulin and creating a vicious cycle.
Paleo and Appetite Management
High-fructose corn syrup is even worse than sugar in that it has been shown to interfere with leptin receptors. Leptin is another hormone that regulates appetite, and by messing with our leptin receptors, HFCS leaves us feeling hungry and liable to consume way more calories than we need.