fruit as pre-race snack

Are there any qualified nutritionists or dieticians out there who could advise on the best snack to have before a 5k? I suggetsed to our local 5k organiser that by having a mass-banana- munch-in before the race it would help promote the 5 a day (fruit and veg) message and would attract abit of media attention. But his reply was that nutritionally, chocolate or something more sugary would be better.... But I was under the impression that a banana would sustain you for half an hour, and that choc would not be as good from a Glycaemic Index point of view because of the fat content. (It would be better I know to give fruit in the goody bag at the end - like they did at Buxton this weekend, but difficult to find a sponsor when 2,500 + runners)


  • You shouldn't need a pre-race snack. Pre-race meal, maybe.

    From an unqualified nutritionist! :-)
  • bananas are supposed to be bad (well, not bad, but not particularly good) because fructose is a disaccharide.

    this would apply to fruit in general.

    try a go gel instead.

    but really, provided you've had a good breakfast, if its only a 5k then why bother?
  • Gill, I'm very surprised that your race organiser gave that reply. I'm a qualified, registered dietitian, though no longer practicing. I think bananas are an ideal pre-race snack.

    Fructose, the sugar in fruit, doesn't need insulin to be absorbed into the cells so won't cause an insulin surge with the subsequent sugar low. Sucrose, the sugar in chocolate, is broken down to glucose and fructose during digestion and so does need sucrose and can cause a sugar low. That would be the last thing you need at the start of the race. The fat in chocolate would also slow down the absorption of the carbohydrate from the chocolate and slow down digestion, meaning that the food is more likely to be sitting as extra mass in the stomach to be carried around rather than actually providing an energy source. Again, the last thing you want at the start of a race.

    I wouldn't advise a "mass munch-in" of any fruit immediately before a race, though, in case all the fibre causes bowel problems during the race. If by "mass munch-in" you mean lots of people eating one fruit rather than everyone eating lots of fruit then I think you couldn't do any better than bananas.
  • Correction, candy, if you'll excuse me. Fructose is a monosaccharide (one sugar molecule). Disaccharides (two sugar molecules eg. sucrose) and monosaccharides are both not quite as good as polysaccharides (many sugar moleules). That's because the longer the chain length of the carbohydrate the less osmolarity the carbohydrate will have so the less binding of water in the gut. This lessens the chance of diarrhoea and improves absorption. There is an optimal chain length, but I've forgotten what it is. These considerations are only really important for races lasting an hour or more.

    I really do think bananas are nectar of the gods prior to a 5K and just wish I'd remembered to take a banana to my 10K yesterday.
  • isn't it right that the more ripe the banana, the higher the GI rating? (ie more sugar than starch so is absorbed more quickly, in layman's terms)
  • In a recent survey on the value of fruits the top fruit to eat before or during exercise (eg half time in a football match) was a mango.If I remember correctly the banawas third. The apple was way down.
    I have found that a nutrition bar helps.
    Why not experiment before races and find out which you prefer.
    It would be interesting to hear about your results
  • lol ratcatcher ok, i was sketchy about the details so i shouldn't have tried to remember them/fill them in

    there was some reason why fruit was rubbish though on some resources i read, that all agreed, and were based upon recent research undertaken for ironman nutrition. but these were advocating proprietary maltodextrin gels and so they should be expected to be somewhat biased!
  • Candy, when I was still practicing (a caveat because I'm out of touch so may well be talking bollocks here but am hoping to get away with it) proprietary maltodextrin gels were the ideal carbo source and definitely the way to go. I do think they are better than fruit - the chain length is what has been found to be ideal from extensive research. It's just fruit is still good stuff and for a 5K I'd definitely go for the cheaper tastier option!
  • ah yeah, my point was that i read that fructose was a rubbish race fuel on some maltodextrin suppliers' website. i'm sure it suggested that fruit was in some cases worse than nothing. but they would say that, wouldn't they?

    either way, i bought into it. its Go, GU and squeezy all the way for me now!

    now if only i could run properly....
  • My ambition is to run far enough to need energy gels.

    [munches wistfully on a cornflake]
  • but bananas are also rich in potassium which may help with cramp ...?
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