Cola is the big one for me.  When I start feeling a bit pudgy, it's the first to go.  I drink a good deal of coffee and tea, but when I worked out the calorie math, it's actually pretty insane how much sugar is in cola:<p><pre><code>  - 250 ml (about 8 oz) of cola has 120 calories
  - 350 ml (about 12 oz) of tea or coffee gets 2-3 sugar cubes
  - 2 sugar cubes is 24 calories
  - Cola has 10x the calories/volume as sweetened coffee or tea
  - I drink 1-2 liters of coffee + tea + cola daily.
</code></pre>
So even switching from cola to sweetened tea is a big cut back.  Other than that, I just do restraint at the grocery store.  Usually I'll allow one chocolate bar every couple weeks.<p>One thing that I learned when we were out in California for the summer is that the portion sizes in the US can really get you.  I shot up <i>15</i> pounds (175 -&#62; 190) in 3 months without noticeably altering my diet.  After 4 months back in Germany it was gone again, without any intentional intervention.