Feet starting to swell up on me when I eat lots of breads and sit all day at conferences without breaks. Any relationship? >

Salt and Gravity. Most breads have salt in them. Salt causes fluid retention. At your conference you are sitting and gravity causes you to accumulate fluids in your lower extremity. Walking causes your leg muscles to contract and helps to pump fluid back up towards the heart. Hence, by sitting you are removing the muscle pump action of the legs. Try snacking on fruit and performing heel raises under the table.