Monday, October 29, 2012

Nutrition for Sports

What's the best diet before, during and after endurance exercise?
This post originated because my partner completed a 165km cycle yesterday conquering Canberra's hills in the Fitz's Challenge (Well done Mike!). Being a dietitian, I was interested in ensuring his nutrition and hydration was optimal before, during and after the event. With so many of us training for fun runs, fitness challenges, triathlons and marathons; I thought I'd post about nutrition for sports.  

Carbohydrate Loading

  • Who should carbohydrate load?
    • Anyone exercising continuously at a moderate to high intensity for 90 minutes or longer e.g. cycling, marathon running and longer distance triathlon
  • The AIS recommends 1-4 days of exercise taper while following a high carbohydrate diet (7-12g carbohydrate/kg body weight/ day)
    • This is sufficient to elevate muscle glycogen (stored glucose = fuel) and can improve performance by 2-3%
  • For example, a 70kg man needs 490 - 840g carbohydrate to effectively carbohydrate load (equivalent to 32-56 slices of bread)
  • In order to consume this amount of carbohydrate, it is necessary to make use of compact sources of carbohydrate such as sugar, cordial, soft drinks, sports drinks, jam, honey, jelly and tinned fruit

Nutrition Before Sport

  • Carbohydrate breaks down into glucose
    • Glucose = fuel
  • Before sport consume a high carbohydrate, low glycaemic index, low fat, easily digested meal 2-4 hours before
  • Aiming for 1-4g carbohydrate per kg body weight
  • For example, a 70kg man needs 70 - 280g carbohydrate (minimum 4.6 slices bread)
  • The table below has examples of foods containing 30g; so a 70kg man would need to consume at least 2.5 of these options to meet a minimum of 70g carbohydrate
  • An example is 3 weet-bix with milk and a 250ml glass of juice

Nutrition During Sport

  • Sports lasting <1 hour do not threaten fuel stores
  • Sports lasting >1 hour do
  • Foods during sports should be high carbohydrate but high glycaemic index (broken down quickly into glucose to give you energy)
  • Aiming for 30-60g carbohydrate per hour
  • An example of 30-60g carbohydrate = 2 x sports gels, 1L Gatorade, 1 x sports performance bar,  8 snackes/jellies

Nutrition After Sport

  • Key nutrient for recovery = protein
  • Aiming for 10-20g protein
  • Works best when coupled with carbohydrate
  • Eat within 30 minutes
    • The bodies protein synthesis mechanism is working best within this time
  • Good post sport snacks/ meals include eggs on toast, fruit smoothie, liquid meal supplement (e.g. Sustagen sport), Up & Go, sandwich with meat or cheese, glass of milk and almonds, protein shake (if low carbohydrate, consume with piece of fruit/ toast for carbohydrates and protein performance bars
  • The table below has examples of foods containing 10g protein

FYI: Protein in excess of need is oxidised as energy and doesn't have an anabolic effect. The maximum amount of protein the body can utilise is 2g protein/ kg body weight/ day.

No comments:

Post a Comment