Sometimes if I’m having a tough morning I think maybe all I need is a big lunch to get my engine revving.  What you eat at lunch can have a real impact on how you feel the rest of the day. If your stomach is grumbling and you’re struggling to think straight, a big lunch may certainly help. But if you’re just feeling tired and run down, it’s important to avoid heavy meals before an important afternoon meeting in order to stay on top of your game. Although skipping meals can leave your brain starved for fuel, a full stomach can also  be a drag on your mental alertness. For those who skip breakfast the temptation to have a big lunch is even greater. But fatty heavy meals can make you feel lethargic and struggling to focus because your blood supply is being diverted from your brain to your stomach for digestion. Research has also linked high fat diets with poor memory. So swap your burger and fries at lunch for a healthy brain boosting tuna, turkey or roast beef and salad sandwich on delicious wholegrain bread. Have a piece of fruit to top it off and, if you can fit it in, go for a quick walk around the block before returning to the office to help ward off afternoon fatigue.