I dropped around 2.5st around 3 years ago and the diet was an integral part. This was before I got into cycling. Ultimately it was all pretty simple.
My exercise routine consisted of 3 x 1 hour session of cardio per week [10mins rowing (approx 2200-2300m), 30mins treadmill run (6k), 20mins cross trainer 2min intervals between resistance/incline 8-8 and 10-10 keeping the steps per minute above 180].
Diet cut down to two weetabix w/skimmed milk breakfast; sandwich, fruit item & kit kat (2 finger) lunch; dinner- protein item with brown rice and veg. Oh yes, reduced the beers intake lots too.
I'm sure nutritionalists would have a field day on this one- didn't consult any books or other materials, simply did what felt right. I was amazed how the body could perform so effectively on what I considered a relatively small amount of energy input.
Might not work for everyone, but I dropped the weight in under 2 months. Diet's a bit different these days as I do more weight training and enjoy my indulgences. Still, very active and have more or less stayed a similar weight for 3 years.
Sorry for the long-winded post, but would say that if they're overly expensive, there's no real need for acai berries :-)