One reason added sugar is easy to over-eat: it's listed under many different names, so no single 'sugar' entry reveals the total. Learning the aliases helps you read ingredient lists like a pro.
The '-ose' family
Most simple sugars end in -ose. If you see it, it's sugar: glucose, fructose, sucrose, dextrose, maltose, lactose, galactose. 'Fructose' is fruit sugar, 'lactose' is milk sugar, and 'sucrose' is ordinary table sugar.
Syrups
Syrups are concentrated liquid sugars: high-fructose corn syrup, corn syrup, brown rice syrup, malt syrup, maple syrup, agave nectar, golden syrup, and 'tapioca syrup' (common in boba).
'Natural'-sounding sugars
Many aliases sound wholesome but are still added sugar: cane juice, evaporated cane juice, cane sugar, coconut sugar, date sugar, honey, molasses, fruit juice concentrate, and 'organic raw sugar.' The body treats them much like table sugar, and the label counts them as added sugars.
The full roster
Other names include: barley malt, beet sugar, caramel, carob syrup, castor sugar, confectioner's sugar, demerara, dextrin, diastatic malt, ethyl maltol, florida crystals, fruit juice, glucose solids, icing sugar, invert sugar, muscovado, panela, powdered sugar, refiner's syrup, sorghum syrup, sucanat, treacle, turbinado, and yellow sugar — among others.
The shortcut the label gives you
Here's the good news: since the 2016 redesign, you don't have to tally all these yourself. The Added Sugars line on the Nutrition Facts panel sums every form of added sugar into one number. The ingredient names still matter for spotting sugar in a product, but the added-sugars total does the math.