i think that anything that is a "do this one simple thing and lose weight" is a crock. mostly because it doesn't take into account where you are starting from. i always see the "drink one less soda a day and lose weight" segments on tv. which would actually work if you just happened to be ingesting exactly one soda's worth of calories over what it takes to maintain your weight or less. in that situation, yes, cutting out one soda would lead to loss. but if you were usually having two soda's worth more calories than maintenance per day, then you would still be gaining weight, just at about half the pace you were before. figuring out what your vices are and how to mitigate them is going to be more important overall than a single, simple rule.
i also look at where i started with sugar. i'd usually use about 24 grams in a cup of tea or on a bowl of cereal. and i wouldn't usually just have one a day. and that's just in granulated sugar that i would add, without taking anything i ate into consideration. it took me a year to wean myself off of that. if my only guideline had been "less than 15 g sugar a day" i would have never have hit it. where i was starting and the goal would be just too far apart and without any sort of helpful reference points, i would have had no idea how to do it. heck, i probably still couldn't hit it now. i would give up without even really starting.
-google first. ask questions later.