Artificial sweeteners like aspartame are even worse than sugar, Dr. Gioffre says. “They are in anything ‘diet’ like diet cola, or sugar free.” Asparatme is a neurotoxin that has sweetening properties to it.  Many people drink diet sodas because they think they are losing weight, but research shows that it can contribute to more weight gain than refined sugar, he adds. “It increases your cravings for carbs, and increases the amount of fat your body stores. It does so by 2 amino acids – aspartic acid and phenylalanine which stimulate insulin and leptin and an adverse way.”