Nutrition for Half Marathon Training

Nutrition for Half Marathon Training

Updated: Mar 26, 2024Kalle Kortelainen

The leaner you are, the faster you go. Weight and body-fat percentage affect your finish time more than training variables. Why is that so? Us runners must move our bodies against the gravity with every stride. Research indicates that just a 5% increase in body weight reduced performance by 5% in a 12-minute test. If you run a half marathon in 90min, that extra 5km would slow you down by more than 4.5min, theoretically. It’s because excess body fat impacts aerobic capacity, makes us overheat quicker and acts as a dead weight. Carrying extra 5kg of body fat is almost the same as carrying a 5kg backpack, which besides slowing you down, also strains your joints. Try running on the anti-gravity treadmill (Alter G) to experience how effortless running is at a lower weight.

You need to be light to run fast but you also need adequate amounts macro-and micro-nutrients to keep your body functioning well, to recover from sessions and to prevent premature aging, injury and burn-out. Starving yourself while popping vitamin supplements won’t cut the deal though. Unless you suffer from any specific illness or deficiency, it’s always the best to cover your micro-and micro-nutrient requirements by eating fresh food. As a long-distance runner, you should focus on foods that are low in calories but high in nutrients. That means lots and lots of vegetables and fruits as a base of your diet with meat, fish, poultry, eggs, nuts and dairy in moderate amounts. Don’t cut any natural food groups unless you have to! For example, why cut dairy out if you aren’t lactose tolerant/sensitive? Natural yoghurt is a great source of protein, calcium and probiotics and you need all those for tissue repair, muscle function, strong bones and healthy gut. Don’t make life unnecessarily complicated for yourself.

How much protein do you need?

You need around 1g of protein per each kilogram of your weight per day. This needs to be spread out through the day. If you are a 60kg girl, you will need around 60g of protein each day. This equals 2 eggs, 80-100g chicken breast/tenderloins, 80-100g fish. If you have more protein that you require, the body will convert it into glucose and use as a source of energy. This process, however, is not that great for your kidneys. The best is to have adequate amounts of protein and get your glucose from vegetables and other carbohydrate-rich foods. There’s no need to count calories and amount of carbs you have unless you are a competitive athlete or suffer from nutrition-related illness. Simply have some carbohydrates for breakfast, lunch and around your training as recommended below. And don’t forget about your good fats! Have one of these each day: ¼ avocado, 30g nuts/seeds, 80-100g fatty fish plus olive oil or any nut oil for your cooking, marinades and dressings.

Guidelines to when and what to eat before and after training


Easy/recovery run/jog or long slow run

- You can do this type of training on empty stomach to increase fat oxidation (lose weight and train your body to utilize fats)

- Wait 30-60min post-training if trying to lose weight the have a proper meal (veggies and fish plus carbohydrates- i.e. quinoa, sweet potato, wild rice wrap etc.)- poke bowl with wild rice or a big omelette with sweet potato or quinoa would be perfect.

High-intensity sessions (sprints, hills, fartlek and any interval work), HIIT and strength training

- Have a small meal before training. Examples: Chief collagen bar, ½ banana with a spoonful of peanut butter, 50g cottage cheese or yoghurt with fruit, small protein smoothie (make sure there are carbs in your smoothie). You can have any small meal/snack that contains carbohydrates and protein and that doesn’t upset your stomach during training

- You can have a protein shake or smoothie straight after training if you are starving then a proper meal a bit later.  


Day 1: A long slow run first thing in the morning


Option #1: Fasted (a big glass of water, black coffee optional)

Option #2: banana+ coffee

Post run:

Breakfast: omelette with vegetables and sweet potato or quinoa


Large salad with 80-100g poached chicken tenderloins (lunch should contain some form of carbohydrates such as 1cup sweet potato, ½ cup quinoa or rice, 1 wholegrain wrap, 1 slice of wholegrain bread, ½ cup legumes and pulses)

Snack ideas (optional; only if starving):


Salmon zoodles

Day #2: A sprint or HIIT session in the late afternoon after work


Warm breakfast salad


Mung sprouts salad with 100g white fish

Pre-workout options: 

  • Chief Collagen Bar
  • Banana with a spoonful of peanut butter
  • 50g cottage cheese or yoghurt with fruit
  • Small protein smoothie
  • 30g nuts/seeds
  • Turkey roll ups

Post-workout (optional):

- Protein shake if starving'


Chilli con carne with brown rice


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