I personally cannot stand eating food if I'm about to engage in physical exercise, unless I'm legitimately seriously hungry. So if I have a random midday idea-of-food, I picture myself about to sprint to the nearest park, or about to swim a few km. Then I check my stomach again - how hungry is it now? I generally don't want anything at that point, but sometimes it does (begrudgingly) need fuel for the imagined activity - only then do I eat.

Mix up a cup of fiber supplement (I use BeneFiber) and drink it 10 min before you plan to eat. You will eat less and feel fuller for longer (eating slowly increases the effect). If you're already choosing healthy foods, portion control is the last barrier to conquering waistlines.

Many people don't get enough fiber in their diet anyway. Just be sure to start drinking more water to overcome the, err, digestive difficulties of higher fiber consumption.

Meditate, listen to your body and mind.