One of the most-discussed issues by runners is what they eat. More specifically, what they eat before going for a run, and how long before the run that they eat it.
I had a friend who, before any of our long training runs, would eat two slices of white bread slathered in jam. I know this, because she would still be eating them as we set off. Which was all very well, until the morning her body told her that blueberry jam was not OK and she had an anaphylactic fit and almost died. I think she's moved on to honey sandwiches these days.
So the consequences of getting your pre-run food wrong can be, well, if not almost lethal, then at least extremely uncomfortable. It's not like there are portaloos set at convenient intervals around the streets for runners to pop into when trouble strikes. I was once turned away by a service station at 5.55am because they didn't open until 6am. Perhaps the attendant inside mistook my dance of desperation outside the glass doors as a show of intent to rob the place? Suffice it to say that run was memorable, too.
Professor Louise Burke is head of sports nutrition at the Australian Institute of Sport and an author of several books including Complete Guide to Food for Sports Performance.
She says what you choose to eat pre- or post-run can make a difference to how comfortable your run is, how fast it is, how well you recover from it and how much weight you lose.
"It all depends on what your nutritional goals are," Burke says. "You might want food that's good for stomach comfort, or for performance if you are doing a race at lunchtime versus a training run at lunchtime. You might want to use your eating to adapt for a forthcoming race. Or you might be exercising for weight loss. There's no one size fits all."
Spread your intake
No matter what outcome you are seeking, Burke says that in the long-term, the best way to manage your body composition and exercise recovery is by spreading protein and energy intake evenly over the day.
It's the approach that Olympic hurdling champion Sally Pearson takes. "If I've got an afternoon or evening session ahead I eat a lighter lunch such as a small stir fry or a meaty salad. I try to eat about 2.5 hours before I train so that I don't feel like I will see my food twice," she told me.
Burke advises to aim to have about 20 grams of high quality protein in a sitting. "Most Western eaters have more protein than they need in a day, but only very little in the morning and lunchtime and half a cow at night. A good protein intake in the morning is a good way of achieving body composition changes."
Protein sources include dairy foods, eggs, meat and fish. Breakfast might therefore include a poached egg on toast. Lunch could be a sandwich with a thick meat or chicken filling, or with a milk drink or yoghurt. If you want to eat fewer carbohydrates you might make it a salad or fruit and yoghurt.
"There's lots of different ways of getting to the same nutritional goals," says Burke. By having a protein-enhanced meal after a run, you can get the benefit of a good recovery, too. And if you are a morning or lunchtime runner who'd also like to lose a bit of weight, this can have the advantage of keeping the munchies at bay until the next main meal.
The key to losing weight effectively is to not be sacrificing muscle mass in the process. "The muscle is the main organ that is burning calories and so the less you have of it, the less you have to be metabolically active," says Burke.
"When you're trying to lose weight it's about a slow restriction of energy intake. If you're in extreme deficit you'll lose more muscle mass as part of the weight loss."
To reduce calorie intake without reducing the satisfaction that food brings, Burke advises increasing your food's nutrient density while decreasing the energy density. "So, few calories per mouthful," she says. "Eat bulky, lower calorie foods - for example, salad and vegetables. That way the volume can be same or even greater, but the calorie value is reduced because of the way you've constructed the foods together."
No need to sacrifice
Viewing your diet as one of sacrifice is no fun and largely unsustainable. Even Pearson doesn't make sacrifices. She says she doesn't believe in the word. "I make choices, so my choice is to eat healthy and eat the right foods for me as an athlete... I do love to eat pasta and pizza, so I eat those meals in moderation," she says.
"There are no foods that are completely off limits for me. At the end of the day you have to enjoy what you eat, and a treat here and there is not going to ruin all your good habits."
Burke says snacks are useful depending on your goals. If you want to lose weight, include your snacks as part of your daily spread of protein and energy. So, if you are planning a lunchtime or after-work run, have snacks that have protein and carbs together such as sweetened dairy yoghurt and fruit, hot chocolate or a cold milk drink.
"Sometimes it's good to have a snack to give you an energy boost for the after-work training session," says Burke. "That way you are refreshed and will train well rather than feel haggard and have an unpleasant experience that discourages you from wanting to keep exercising in the future."
There's always the need to manage stomach comfort. You just have to experiment with what pre-run food your body tolerates best and when. The upshot of it is that once you know what works, you'll be far less likely to have to make unscheduled pit-stops at service stations.
Do you have a fail-safe pre-run snack?