We all know that a healthy diet is a balancing act of carbs, proteins and fats. But there's one factor runners often neglect, warns sports nutritionist Becky Stevenson (proactivate.co.uk): "Whether you've done an easy 20 minutes or been solidly running for hours, you need the right recovery food for that session." Work your diet around your training with our guide to common post-run problems.

Post-run You crave more fuel than you burnt
Starving after only 20 minutes? The glycogen stores in your muscles and liver could be too low. Stevenson recommends low-GI foods like oats or legumes three hours before a short run. Then fruit with low-fat yoghurt should be enough afterwards. "But don't forget the body often mistakes thirst for hunger," warns nutritionist Barbara Cox (nutrichef.co.uk). Use a urine chart indicator to find out if dehydration is the problem and replace table salt with Himalayan Crystal Salt (himalayancrystalsalt.co.uk, £3.50 for 250g): rich in minerals, it optimises hydration.

Post-run You train hard but don't want to lose weight
The trick to maintaining bulk is mixing simple and complex carbs. Stevenson recommends you have the same wholemeal toast or porridge as any other runner - but drizzle it with honey and berries for a sugar boost. Cox favours flapjacks as a high-density energy food, and using the juicer also helps: "Juicing veg, rather than eating it, means you end up with a higher number of calories in a smaller volume. And you can freeze the juice into 'shots' to add an energy boost to other meals as you cook."

Post-run You're knackered after a 20-miler
After heavy training, you have a 20-minute window to top up your glycogen levels with carbs. Within the hour, you also need a full meal; the body converts carbs into glycogen, but this is easier if you eat protein too, according to a study in Medicine and Science in Sports and Exercise. Aim for a carbs-to-protein ratio of 4:1. Cox suggests chicken salad with bread, or meat stew with rice. "Or try quinoa, which is a protein source in itself," she says.

Post-runYou're a queasy rider
"When you run hard or long, the gut can become ischemic," says Stevenson. "That means it doesn't have a great blood supply because everything's gone to your legs." A sensitive gut can't handle big meals, so avoid bulk beforehand with meal replacement shakes like Complan or Maximuscle. These are absorbed far more easily than food and if you still have problems, Stevenson suggests diluting the shakes down from six per cent concentration to roughly four per cent. Then follow your normal post-run recovery schedule, sticking to dry and plain carbs like bread, bananas or crackers.

Post-run You're a night owl
Even if you run just before bedtime, refuelling is vital. "Otherwise your liver stores of glycogen will be too low to sustain you the next day," says Stevenson. "Go for a small amount of carbs which are easier to digest, without too much protein." It is best to eat your main meal two hours before the run, so a snack will be enough afterwards: Cox suggests crudités with hummus as a quick pick-me-up. Alternatively, have a small bowl of pasta with tomatoes, or a packet of oatcakes.