In the middle of the day you need energy and carbs for your brain to function properly. Take a break – don't eat in front of your computer. Be careful when eating out – you may easily eat more than the recommended 400-500 calories. For lunch, you need to eat 50 to 65 grams of carbs, 20-30 grams of protein and about 15 grams of good fats. Fiber is also necessary – aim for about 8 grams. Fish, poultry or meat with pasta or veggies is a great choice. You can also eat a salad with whole grain bread – the variety of choices for lunch is unlimited.