
07/12/2020
If you exercise -what should you eat and when?
To make the most of your exercise regime it is important to think about what you eat. The food you need depends on the type and intensity of your workout. Your body can store around 2000 carbohydrate calories in glycogen in your liver and muscles. Once you have used this stored energy you run out of fuel unless you add to it.
Before Moderate Exercise
Ideally eat a slow releasing low GL meal 2-4 hours before training. Aim for 2.5g carbs per kg of body weight. It is important to eat before training to ensure that you have adequate initial glycogen levels and slow but sustained energy release. Low levels of blood sugar result in sluggish performance and early fatigue. Thus, you will not be able to exercise for as long or as well. Good options include
o Jacket potato with beans, cheese, tuna, coleslaw, or chicken
o Sandwich/bagel filled with chicken, fish, cheese, egg or peanut butter and salad
o Pasta with tomato-based sauce, cheese, and vegetables
o Chicken with rice and salad
o Vegetable and prawn or tofu stir-fry with noodles or rice
o Mixed bean hot pot or fish pie with potatoes
o Wholegrain cereal/ porridge (e.g. wheat flakes, muesli, or Weetabix) with milk or yoghurt
In moderate exercise there is no need to eat anything during exercise as you will have enough stored energy. However, it is important to keep your fluids up.
Before and During Prolonged Exercise
For prolonged exercise (i.e. for longer than one hour), it is a good idea to have a high Glycaemic Load snack 5-30 mins before exercising to provide instant energy and to spare glycogen. It is not good to eat too much and you may find that a more liquid meal is easier to digest. Avoid foods that are high in fat as these take longer to digest and divert blood to the stomach to aid digestion. This type of snack will result in a substantial burst of blood sugar, immediately before exercise. Good snacks include:
• bananas
• isotonic sports drink, smoothies
• dried fruit/ cereal bar
The muscles can take up 30-60g of carbohydrates per hour during aerobic exercise. It is easier for your body to absorb if given in small doses. The optimum approach appears to be 15 – 30 g every 30 minutes. E.g. A banana has 23g of carbohydrate per 100g.
After Exercise
Following exercise your glycogen stores will be depleted. It is important to eat soon after exercise as your ability to replace lost glycogen is highest in the 2 hours immediately afterwards. Timely replacement of glycogen can result in improved glycogen stores over time. Eating protein after exercise helps with muscle rebuilding. Overall, the optimum post work out meal should include 20-40 g of protein and 60-120g carbohydrate. If you are training late in the evening a good option would be a protein shake or smoothie with added protein powder. If earlier in the day a balanced meal of carbs, protein and veg is ideal.