Making healthy, performance-enhancing food choices isn't just about picking a salad rather than a quarter-pounder in McDonalds, or replacing Mars Bars with apples on your weekly shopping list. The decisions we make every time we sit down for a meal, or grab a quick snack, can have a bearing on how we run, perform in an important business meeting and even how well we sleep. Don't worry, though, you're not going to have to make drastic changes to your diet. Just a few simple tweaks will make the good food you're already eating even better. Now, will it be mushrooms, fried onion rings...

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On waking

Good Coffee
Better Water and lemon juice
Best Water

Why? You lose up to 600ml (a pint) of fluid through sweat during the night so replenish your losses with an early-morning drink. Coffee may be a good choice if you're planning an early run - caffeine can make you feel more alert and wide-awake, and it helps increase endurance - but excessive amounts can increase nervousness, trembling and even trigger the runner's trots. It's also a diuretic unless you're exercising.

Water with lemon tastes more refreshing than coffee and will rehydrate you better; but, best of all, omit the lemon juice - it's an acid bath for your teeth - and drink plain water.

Breakfast

Use your loaf: a fruity snack in the morning gives a slow release of carbs

Good Bran flakes with semi-skimmed milk
Better Muesli with grated apple
Best Porridge with toasted pumpkin seeds and honey

Why? To kick-start your metabolism and replenish liver glycogen reserves, you need nutritious carbs. Fibre-rich cereals are good choices - a bowl (30g) of bran flakes supplies around a quarter of your fibre needs, 50 per cent of the RDA for folic acid and 25 per cent of the RDA for the B vitamins and iron. Yet they contain almost twice as much salt as salted peanuts (1.87g versus 1g per 100g).

Muesli with a portion of fresh fruit makes a better choice. Oats and rye flakes are rich in cholesterol-lowering soluble fibre, naturally rich in B vitamins and iron, and apples are rich in the cancer-protective antioxidant quercetin. For the longest-lasting energy fix, try porridge (use rolled oats, not instant oats, as they have a lower glycaemic index (GI: the rate at which energy is released): 42 versus 65) with honey. Add pumpkin seeds for their Omega-3 fat content to help boost oxygen delivery during exercise and promote rapid recovery.

Mid-morning snack

Good Rice crackers
Better Wholemeal toast with honey
Best Fruit loaf

Why? A carb-rich snack mid-morning will keep your blood sugar levels steady and your mental concentration high. Rice crackers provide quick energy (GI = 91, almost as high as pure glucose at 100), but may spike insulin levels too rapidly in some people. Cut the GI and risk of a drop in blood sugar levels by adding peanut butter or opting for wholemeal toast and honey instead. The GI lies between 69 and 58 and you'll get extra fibre and iron. For a slower energy release have a slab of fruit loaf. The dried fruit and fat in the loaf lower the GI to a respectable 47.