The problem with express lunches are that often we just don't eat enough to fill us up. That naughty panini, hamburger, packet of crisps or slice of pizza might be hideously calorific, but in terms of quantity they leave a lot to be desired! Which means that, far from feeling full after treating yourself to ten zillion or so calories, you end up feeling hungry again a few hours later.
Sometimes we just don't eat enough at lunch. It's easily done: you're running out of time and you think if you grab a bar of chocolate, an apple and a yogurt at your desk it's enough. Which is just cruel when, a few hours later and despite the chocolate, you're starving hungry!
To avoid afternoon hunger pangs and inevitably gorging yourself on anything edible within a three-mile radius, you need to have a substantial lunch that will keep you going. Your lunch should contain at least 400-500 calories from filling complex carbs, and plenty of fruit and veg to fill you up.