Diet Coke is something of a problem child for Coca-Cola, as sales continue to slump.<br />According to Business Insider, it's become the weakest part of the company's product lineup.<br />However, it can't stop selling it--for fear of alienating loyal Diet Coke lovers like President Donald Trump.<br />So instead of changing the core brand, new flavors are being added to boost sales and turn the franchise around. <br />
