I am a regular on BBC 2's Steve Wright show where each month we discuss a hot topic in health and nutrition. Not surprisingly, with seven million listeners the interviews can trigger a sizeable response. One of the most popular topics in the past year was how to fuel a marathon. If you are anything like me, you may well have spent some time over the festive break planning 2016's challenge. For the record, I’ve signed up to the Edinburgh half marathon this year - with a mini-triathlon in there too just for fun.

Whether it’s a 5k, 10k, mud race or half or full marathon there’s no getting away from the fact that it all comes down to preparation, but first some facts.

If you have signed up to a race in order to shift some weight, you’d think that a demanding training regimen of this type would result in significant weight loss for anybody - however, many runners report actually gaining weight during marathon training...why?

The number of calories you burn while running a marathon will depend on a number of factors - men typically require more energy for physical exertion than women, your resting metabolic rate which is determined by your age and your body weight will impact too. However, the range is around 2,000 to 3,000 calories. Pretty much what was consumed during Christmas dinner for most people.

Using that example, a common mistake that runners make (no matter what the distance) is overestimating  how much they need to eat in response to their training. Running is not a free pass to eat anything because you “earned” it. Add in sugar-loaded gels and drinks and it’s easy to actually end up gaining weight!

So, if you are about to embark on a training regime - which is wonderful for your overall cardiovascular health, not just weight management -  you need to fuel and refuel properly. The last thing you want is coming back from a morning run to find you are out of oats, the kids have taken the bananas to school and the peanut butter was eaten at by your other half.

Stock your cupboards up with the essentials; dried fruits, root veggies to juice (more on beetroot in a minute), oats, avocados, peanut or other nut butter, almonds and you will be on top of your energy levels without dragging your tired sweaty body down to the local supermarket post run.

What about sports or energy drinks?

Well, the trouble is that the energy in these drinks is provided by rapidly absorbed carbohydrate in the form of sugar, along with stimulants. While this provides a short-term rise in blood sugar, it’s likely to be followed by a dip in energy after that sugar is either used up or stored.

Sports drinks are are little better as they are specifically designed for athletes and active people who frequently train at high intensity for more than an hour. They are proven to improve performance and do have their place, but it’s important to know that, in the same way as energy drinks, the ‘energy’ they give you is simply extra calories from sugar. So, you can easily undo the calorie burn of a workout by visiting a vending machine embellished with sports drinks branding.

There are some sports drinks that don’t contain sugars and are designed solely for rehydration – however, in most circumstances, water will do this job just as effectively. 

Alternatively, be thrifty - helpful after the festive spending sprees anyway - and make your own by mixing 250ml of water with 250ml of fruit juice and adding a tiny pinch of salt. One or two of these per hour will give your muscles the carbohydrate they need to sustain your effort level and make recovery easier.