marathon training nutrition guide

Marathon Training Nutrition Guide

Marathon Training Nutrition Guide

PT Manager Matt at JDP Fitness completed his first half marathon last year, during which he realised how important nutrition was to aid not only his training but his recovery. Read below for Matt’s guide to Marathon Training Nutrition

Nutrition is an important pillar in anybody training protocol. However, once you start putting your body through the intense physical trauma of training for a marathon then your nutrition takes centre stage. If you are not feeding yourself correctly or eating properly to aid your recovery than your training will fall by the wayside. Their is a reason why top level marathon runners invest so much time into ensuring they are resting and eating the correct amounts at the correct times. At a novice level the difference in getting your nutrition spot on and just eating whatever you want will have a huge impact on your finishing time at the end of your training phase.

Read on for our ultimate guide to marathon training nutrition.

Body Composition

An important factor of marathon training nutrition that is often overlooked is your overall body composition. Runners will focus on the performance aspect of training with no consideration for overall body composition. However recent studies have shown that your overall body composition is equally important.

Each runner’s optimal racing weight falls near the bottom end of his or her healthy weight range because excess body fat is dead weight that increases the energy cost of running. A typical runner who sheds just one pound of body fat could see a one-minute improvement in his or her marathon time without any change in fitness. Think about the type of athlete you are trying to emulate. Paula Radcliffe at her prime was very long and lean. That is not to say that everybody should aim to look like this. But even the most casual weekend warrior runner can make a dramatic difference to their overall time in a race by ensuring they are as trim as possible.

Complicating matters for runners is something called the compensation effect. The more a person exercises, the more his or her appetite increases and the more he or she eats. Simply ignoring the increased appetite is not a viable solution, but neither is an extra-large, double-cheese pizza.

Instead, runners must increase the quality of their diets. High-quality foods such as vegetables are less calorically dense than low-quality foods, satisfying the appetite with fewer calories. The six high-quality food types are vegetables, fruits, nuts and seeds, whole grains, lean meats and fish, and dairy. And the four basic categories of low-quality foods are refined grains, fatty meats, sweets and fried foods.

Carbohydrate Intake

The common assumption now is that “I am doing loads of cardio, I need to increase the carbs”. Training hard and frequently does not give you carte blanche to just eat every carbohydrate in sight. That being said your levels do need to be appropriate for the amount of exercise you are doing.

Lately, some experts have suggested a low-carb diet is better, arguing when runners maintain a low-carb diet their muscles become better fat burners, an adaptation that spares muscle glycogen in marathons and thereby pushes back the wall.

Studies have shown that low-carb diets do indeed increase fat burning during running. However, this effect has not been linked to improved endurance performance. Meanwhile, new research has reconfirmed that runners aren’t able to train as hard on a low-carb diet because it produces chronically low glycogen stores.

At the end of the day we are all individual and different runners will work more efficiently with different levels of carbohydrate intake. Ultimately it is up to the individual to test the levels of carbs they need to take it to still maintain the race pace they are looking to emulate on the day. But, as a guideline this table works well for the intake you should aim for depending on training time.

Average Daily Training Time (Running and Other Activities)

Daily Carbohydrate Target

30-45 minutes

3-4 g/kg

46-60 minutes

4-5 g/kg

61-75 minutes

5-6 g/kg

76-90 minutes

6-7 g/kg

90 minutes

7-8 g/kg

>120 minutes

8-10 g/kg

Sports Drinks

Sports drinks aid running performance by limiting dehydration and supplying muscles with an extra source of energy. But you do not need a sports drink on every training run. Research has shown that sports drinks have no effect on performance in hard runs lasting less than one hour or easier runs lasting fewer than 90 minutes.

What’s more, other studies suggest the carbohydrates in sports drinks act as a physiological crutch by limiting some beneficial fitness adaptations that occur in response to training. Improvements in the muscles’ fat-burning capacity and other adaptations depend partly on the depletion of muscle glycogen stores during workouts. Sports drinks attenuate glycogen depletion and thereby blunt the body’s adaptive response to the run. Sports drinks are imperative for longer and harder workouts, but relying too heavily on them in training may make you less fit.

Carb Loading

Earlier I said a low-carb diet — specifically a high-fat, low-carb diet — increases fat burn during running, but this benefit comes at the cost of reduced training capacity. For this reason, it’s not recommended runners use such a diet as their normal training diet. However, research has shown that a short-term high-fat diet that immediately precedes the traditional pre-race carb load offers the best of both worlds. 10 days of fat-loading are enough to increase the muscles’ fat-burning capacity, while the subsequent three-day carb load ensures muscles also have plenty of glycogen available.

To get these benefits in your next marathon you’ll have to get 65 percent of your calories from fat every day for ten days starting two weeks before your race. This means virtually everything you eat will need to be high in healthy fats. Recommended staples for fat loading are avocados, Greek yogurt, cheese, eggs, nuts, olives and olive oil, salmon, and whole milk.

Switch from fat-loading to carb-loading three days before your marathon. Aim to get 70 percent of your total calories from carbs during this period.

Water Intake

Every runner knows it’s important to hydrate before the start of a marathon, but it’s easy to go overboard. You don’t have to drink a lot to achieve full hydration after a night of sleep, and any excess will only force you to wait in long toilet lines before the start and — worse — stop for bathroom breaks during your marathon. Limit morning of, pre-marathon fluid intake to 24 ounces and don’t drink anything in the final hour before the race begins.

Here’s another suggestion: Instead of drinking water before your marathon, drink beetroot juice. Why? Beetroot juice is packed with dietary nitrates, which help blood vessels dilate, increasing blood flow to muscles during exercise. Studies have shown that drinking half a litre (about 17 ounces) of beetroot juice two to three hours before running can enhance performance.

However our top tip is to see if beet juice helps you by testing it before some practice runs. A word of caution: Don’t try it for the first time on the morning of a marathon.

If you have any questions on our Marathon Training Nutrition, then contact any of the team via the link.

author: jasonpatmore

I am a Personal Trainer and coach based in Liverpool Street.


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