Liquid sugar. I used to drink a glass of OJ each morning. Back when I didn't know that it contains about 10g of sugar per 100ml. Which is almost the same as in Coca-Cola. Yes OJ has vitamin C in it, but it's still a big shot of sugar into our bloodstream. And if it's followed by sweet breakfast cereal or pastries then we're over the NHS guidelines of 5 teaspoons max of sugar per day before we've even left the house. I just don't bother with fruit juices any more. Or sugary soft drinks.