Karen Reid, a nutritionist for the English Institute of Sport, answers your latest questions about preparing for the London Marathon.

This is your last chance to ask Karen a question before the Marathon, so make sure you get them in before Monday!

J Parks, 52, Saint John
When tapering for a marathon, what type of carbs should a guy consume and how much? Also, do we keep eating protein?

Karen says:
Yes it's important to continue to eat a balanced diet, which includes proteins, essential fats and fruits and vegetables as well as plenty of carbs.

Proteins are particularly important in a runner's diet

Proteins are particularly important in a runner's diet, to help repair the exercise induced muscle fibre damage that occurs during repeated training sessions. Depending on your body mass, around 7-10gms of carbohydrate per kilogram of body weight is appropriate during the days leading up to the marathon.

I would suggest you go for good helpings of starchy carbs at mealtimes and top up your carbs between meals with more compact snacks such as scotch pancakes, jelly sweets, pots of Mullerice, dried fruits, and soft drinks.

Caroline, 12, London
Hi, I'm running the Mini Marathon. I did it last year and it went well but it was hard getting up at 5:30 in the morning to make the coach on time.

I was wondering if, as well as getting to bed earlier I could improve my diet to stop me feeling as tired. I eat healthily but is there a particular food group I should eat a lot of in the build up to the race?

Karen says:
It is very important that you recover well after each training session, otherwise you will feel increasingly tired. Eating a carbohydrate based snack within the first 30 minutes after training, and rehydrating with a sports drink or water is essential for good recovery.

Ideal recovery snack choices include dried fruit, bananas, fruit loaf, scotch pancakes, and a low fat flavoured milk drink. Eating lean red meat 2-3 times per week and plenty of green vegetables will ensure that you have good iron stores, as low iron status is also associated with tiredness.

Clare, 35, Nottingham
I am running in the London Marathon and have been doing my long runs on a Sunday, usually after lunch. Last week I tried out the 'race day' timings and ran after breakfast - a big bowl of porridge.

I was starving after about an hour and what I was drinking was hitting an empty stomach and not feeling good. Consequently, I don't think I drank enough and felt dreadful around 17-18 miles (which took me about 3 hours).

I think I may need to eat something during the race to keep me going and keep me drinking. Or should I just get up even earlier and try for two meals before I start?

Karen says:
It's very important that you rehearse any race day eating strategy first so you can find out what works best for you.

I would recommend you try eating an earlier breakfast, followed by a light carbohydrate based snack no later than 1 hour before the start of the race. Ideal snacks might be a white bread honey sandwich, rice pudding or scotch pancakes.

If you can manage any solid food during the race, another honey sandwich or pancake, or some jelly sweets should be easy to carry

Matt, 34, Edinburgh
I've just had a bad bout of diarrhoea a couple of days after my last long run of 20 miles. Can you recommend how I should start to re-build up my carbohydrate stores?

Karen says:

Liquid carbs in the form of sports drinks are readily absorbed

Liquid carbs in the form of sports drinks are readily absorbed, and also replace electrolyte losses associated with the diarrhoea. Cordials, soft drinks and sugary foods such as jelly, sweets and sorbets are also useful.

You can then move onto mashed potato, pasta, and white bread, and avoid high fibre sources of carbohydrate such as wholemeal products, dried fruits and baked beans and pulses until you are completely recovered.

Pele, 32, Franklin
I have been training for a marathon since January, and have not lost any weight. I do notice a change in my body, but this is very frustrating as I am working out more than I ever have before in my life.

If my diet is essentially the same as it was before my training, can you tell me why I'm not losing weight?

Karen says:
It would be interesting to know if your body composition had changed as a result of your training by measuring your body fat at the start and again recently. This would tell you if you have in fact lost body fat and increased muscle mass which would explain why you have not lost any weight.

You do mention that you have noticed a change in your body which suggests that this might in fact be the case.

Judith, 35, St Helier
This is my fifth marathon and I can't get a suitable sports drink. I'm always sick around the 20 mile mark, so I think water will be my only sports drink this year in London - will that be okay? My PB is 4.01 and I'm desperate to get under 4 hours.

Karen says:
Keeping well hydrated and taking sufficient carbs are important for sustaining a good pace throughout the course of the race.

If you cannot cope with any of the sports drinks on the market, I would suggest you experiment in training with water and jelly sweets, or a squash with a tiny pinch of salt as alternative options for the marathon.