We know it’s bad for us, but we can’t stop eating it. Why do our taste buds so frequently override our brains and tell us that eating that bag of potato chips, or that second snack cake, is worth the risk? Apparently, it’s not really our fault—junk food is addictive because food companies have designed it to be that way.

In his book Salt Sugar Fat: How the Food Giants Hooked Us (and a New York Times article adapted from it), Michael Moss digs deep into the strategies that food companies use to keep the populations buying their food, twisting science and manipulating ingredients. A few of their tactics are more complicated than you may realize.

Howard Moskowitz runs a consulting firm for the bigwig junk food companies, and he’s responsible for a lot of the delicious foods we eat. The secret, Moskowitz told Moss, is something he calls “the bliss point”—that specific balance of flavors that isn’t too much, but isn’t too little, and leaves your brain craving more. The product can’t be too flavorful, or it creates what’s called “sensory-specific satiety”—a big flavor overwhelms the brain and dampens your desire for more. By contrast, boring flavors don’t engage the brain enough, and no matter how much you eat, it never feels like enough. For most companies, reaching the “bliss point” is a simple process: just add sugar. 

Other junk foods trick us into eating more than we ever should with something called “vanishing caloric density.” Steven Witherly, a food scientist and the author of Why Humans Like Junk Food, told Moss that Cheetos are “one of the most marvelously constructed foods on the planet, in terms of pure pleasure.” The puffy snacks melt in your mouth, tricking your brain into thinking there are no calories in it and convincing you to keep eating it forever.

As the population becomes increasingly concerned with the amount of sugars, salts, fats, and other ingredients that could be harming their health, junk food companies are forced to adjust the makeup of their popular snack foods to convince us that they’re still good to eat. By dialing down on the “bad” ingredient—for example, salt—and increasing the other not-quite-healthy ingredients to make up for taste, the company can label their product as “low sodium,” making the consumer think they’re choosing a healthier option, Moss says.

Unfortunately, food companies are driven by the need to survive—if they market something healthier but not as tasty, they risk going out of business because their competitors are still offering sugary, addictive products. But with new research showing that sugar may be as addictive as cocaine and books like Michael Moss’s, we could use our awareness to fight back against the manipulation of the food industry.