There are four ingredients everyone ought to avoid, or at least greatly restrict. They're what fitness expert and author Paul Chek calls the white devils: flour, dairy, salt, and sugar. Bread and other products that use refined flour are high on the glycemic index and shouldn't be a staple. Milk is full of sugar, causes intolerance, and is overrated for bone health. We get far too much salt thanks to our processed foods. Then there's refined sugar, the most important to cut back on – and the trickiest. First of all, our sweet tooth goes back millions of years to ancestors who didn't have enough good fat in their diet. As soon as you cut sugar out of your diet, you'll lose the craving for the stuff entirely and won't even be able to handle a regular soda. Another reason sugar is hard to avoid is that it's in everything – it's even in salad dressings. My rule is to straight-up avoid processed sugar, especially high-fructose corn syrup, which is hidden in so many foods.