How to avoid gastric upset when running

One of the most common issues during endurance running is gastric upset – cramps, vomiting, diarrhea. There is no one cause of this, and it is often very individual, however there are a number of things you can do to minimize the chances are this happening.

1. Hydration. If you become dehydrated your stomach will no longer be able to absorb carbohydrates effectively. It only takes a 2% variation in your hydration for issues to start occurring. The best way to work out how much water you need is to do a sweat test. This is easily done on one of your training runs. Some people lose 500mls water per hour others lose twice this. A guideline is around 600mls per hour for females, 850mls for males – though it is also very dependent on your body weight.

2. Practice absorbing carbohydrates (sugar). Use your training runs to practice absorbing carbs when your body is under stress. There may be times when you don’t actually “need” the carbs ( run is less than 90mins) , but if you are someone who suffers from gastric upset, then it is important to practice absorption during training. Carbohydrates absorb best into the small intestine when in a less than 10% solution. So if you are taking on board 20gms of carbohydrate (ie a gel or bloks) you will need a minimum of 200mls water ( 20/200 =10%) . 6-8% solution is preferable for the sugar to be more readily absorbed – so that would be closer to 250-300mls of water.

3. Different types of sugars. Not all carbohydrate gels or drinks are created equal. There are endless mixed messages in the market place over which sugar is best for fueling. Glucose, fructose or maltodextrin ? The answer – whichever works best for you. If you have a sensitive tummy, try using different brands – choose one without fructose, and perhaps one that is 100% maltodextrin, or if gels are not working, try some blocks/chews or a liquid fuel.

4. Avoiding fibre. If you would like to have “real food” as part of your nutrition make sure that you chose low fibre and low fat to reduce your risk of gastric upset. Examples are white bread, potato, bananas, pikelets, white rice. Running a marathon is not the time to be super healthy with a multigrain sandwich, nuts and seeds or homemade muesli slice made with oats – these will potentially have you taking a detour to the loo. If you are someone who suffers gastric upset, then stick to low fibre foods for a few days prior to your event.

5. Have a plan, but be flexible. – try to stick to your nutrition plan that you have practiced in training. However, if you start to feel sick during the race, back off the fuel and sip water for then next 20-30 mins and try again.

Fat Adaption – What does it mean and does it make you a better athlete?

Exercise for Health

There is a lot of information and talk about “fat adaption” at the moment, is it for you?
Firstly lets understand the two energy systems Anaerobic and Aerobic.
Anaerobic (without Oxygen) is exercise at high to very high intensity – fuel is stored ATP along with blood sugar and muscle glycogen. There is no fat used as fuel during high intensity exercise. If you are an athlete that competes in events that require a sprint finish – fat adaption is of no benefit. It will actually decrease your body’s ability to utilize carbs when they are needed most – hence performance will suffer.
Aerobic exercise– low intensity up to 60% of max effort, (long slow, endurance exercise) however does use fat as one of the substrates for fuel – along with carbohydrates. The amount of fat used depends on how well the person is able to access their fat stores – this is essentially what “fat adaption” is about – training your body to use fat as the primary source of fuel during prolonged endurance exercise.
So should you fat adapt?
Research is still minimal at this stage, however it is widely known and accepted that it doesn’t work for every individual, and for some it can be a detrimental to times and performance. Around 1/3rd of endurance athletes find it of benefit, 1/3rd find it no benefit, and 1/3rd find it decreases their performance.

Consider trying it if:
1. If you are an endurance athlete that suffers from gastric issues during prolonged endurance events then it might be beneficial, as when you are fat adapted you require less carbs (you still need to fuel with carbs, but the volume decreases)
2. If you carry excess weight, or have insulin resistance (or Type 2 diabetes), then fat adaption may be a good option to help control these symptoms.
3. You have a break in racing for a minimum of 2 months so that you can follow a high fat diet protocol in order to achieve ketosis adapt your body to burn fat more efficiently

Do not consider if:
1. You enjoy competing in events/training that are at medium – high intensity
2. You are not overweight or insulin resistant and enjoy a balance diet that includes good quality carbohydrates, proteins and fats.

I follow a LCHF (Low Carb High Fat) diet – is that the same thing?

As a practitioner I find that many people tell me they are following a LCHF diet. However, in reality, they are actually following a balanced diet. Over the past 20 years our Western diet has increasing moved towards a higher level of processed carbohydrates. If you remove processed carbs from your diet and eat more whole foods such as vegetables, fruit, wholegrains, protein and healthy fats, this is a balanced diet. I call it Lower Carb, Higher Fat.
It is important to remember that this doesn’t mean a high protein diet. Every balanced meal should contain some good quality carbs, lean protein and healthy fats.
Finding the right balance of carbohydrates that suits you is dependent on your training load, your goals, your weight, your genetic make up.

I follow intermittent fasting protocol 1-2 days per week – is that the same thing?

No. Intermittent fasting is a great strategy for stimulating hormones that encourage fat burning, and it can be a great tool for weight loss. However, it will not impact your body’s ability to burn fat over carbohydrate during exercise.

Here are two quotes from the “gurus’ of fat adaption:
Prof Tim Noakes
Q: Is it right for everyone?
A: No diet is right for everyone. LCHF is best for people who are insulin resistant.
Dr Steve Phinney
For many people, wholegrains are an excellent source of energy and a healthful food. But when people become more insulin resistant, they have a difficult time disposing off those carbohydrates. We’re not saying get rid of wholegrains in the diet, we’re just saying reducing them in the most vulnerable fraction of the population that can’t tolerate them.

Why are Omega 3 fatty acids so important ?

The human body can make most of the types of fats it needs from other fats or raw materials. However, that is not the case for omega-3 fatty acids – the body can’t make them from scratch, but must get them from food. They are therefore called Essential Fatty Acids

What makes omega-3 fats special?

Omega-3 fats have been shown to:
• prevent heart disease and stroke
• reduce chronic inflammation
• help control auto immune disease such as lupus, eczema, rheumatoid arthritis, psoriasis, crohn’s disease and Type 1 diabetes
• reduce symptoms of anxiety and depression, and ADHD in children
• reduce asthma in children
• alleviate menstrual pain
• improve bone and joint health
• improve skin health – hydration and oil production, prevent premature ageing and acne, and protect from sun damage

There are three main omega-3s:
• Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) come mainly from fish

• Alpha-linolenic acid (ALA), the most common omega-3 fatty acid in most Western diets, is found in vegetable oils, walnuts, flax seeds, chia seeds and leafy vegetables. Unfortunately ALA is not very active in the body, and is mostly used for energy, so whilst it is a very good source of healthy fat, it doesn’t really contributed to EPA/DHA intake– as only around 5% is converted to EPA, even less to DHA.

What is best way to ensure Optional Intake of EPA/DHA ?
Eat fatty fish 2 times per week minimum. One of the easiest, most convenient and economical ways is to eat tinned Sardines.
I find lots of my clients are happy to eat tinned Tuna, which provides around 150mg of Omega 3 per serve, but Sardines provide 2900mg per serve – nearly 20 times as much.
There is no set standard for how much combined EPA/DHA you need each day, although healthy experts generally recommend 250- 500mg per day. So one tin of tuna per day is not enough, whereas if you had tinned Sardines 2 times per week instead –you are smashing it.
Before screw up our nose and say “yuk” …. Spend the $3 and just try them …you might be surprised.
My favourite way is to have them as part of a big salad for lunch, others enjoy them on sourdough toast, or just straight from the tin as a snack.

Hydration for Endurance Running


The biggest concern for an endurance event is dehydration or hyponatremia.

Dehydration by 2% can start to impact performance and Overhydrating by just 2% can cause hyponatremia. You need to avoid both.

The best way to know how much water you need is to do a simple sweat test. This is easily done on a 1 hour mid week run. As a broad guideline the average sweat rate is around 600ml -750ml per hour – please consider that this varies greatly depending on pace, air temperature, fitness level and you – some people are just sweatier than others.

So why is staying hydrated so important during your run?

Water is key in keeping your blood, which contains much needed oxygen and sodium, flowing quickly and easily to your heart, lungs and muscles—as well as helping every body part needed to run well function at its peak. However, when you become dehydrated, consequently your blood becomes thicker, which makes your heart work harder to pump blood to the body parts that need its fuel.

Is it possible to over-hydrating ?

Yes, especially for beginner runners. You can actually drink too much water while running – this is called hyponatremia. When you are new to running, you are probably not running at the same effort as a veteran runner (yet), which means you might not be sweating as much. In other words, you don’t lose liquid from your body as quickly as someone running at a harder effort and pace.

Finding the right balance for you between dehydration and over-hydration is something you will learn as you continue to consistently run.

When you sweat during running you are also losing salts – mostly sodium. For endurance events it is important to replace these salts – as it improves hydration – allowing the water to get into the cells, reduces the risk of hyponatremia and also reduces the risk of muscle cramps.

For an endurance event consider taking a salt replacement capsule, these are available from good sports stores – popular brands are Hammer Endurolytes, or Salt Sticks.

Some fuel sources (liquids, gels, chews etc ) have salt added to them – check your labels, generally speaking it won’t be enough for those running 6+ hours.

Fuel for UTA 50km

These are general guidelines for the amount of fuel you need to carry with you in the mountains. It depends on your fitness, pace, experience and body weight, this gives you a guideline – it’s better to come home with some left over gels and a bar or two than to run short.

How Much Fuel is required for an endurance run 5- 9 hours ?

On average:

Males – 70 grams carbs per hour (280 calories)

Females – 50 grams carbs per hour (200 calories)

You should be aiming to consume fuel every 20- 30 mins. Fuel can be liquid or solid. Start fuelling within the first hour. DO NOT wait until you are 2 hours into the race.

* for 100km, you may need more per hour than you would for a 50km event.

What does this look like?

Run estimated 7 hours – ie 50km UTA

Males – you will need to carry 490 grams of carbs (1960 calories)

= 20 gels or 18 Bananas!  ……..YES – it is a lot! ….

I suggest you take a few different options:

Example: 6 gels, 4-5 energy bars, a sandwich , a banana, and the rest (another 100 grams carbs/400 calories) in liquid like Tailwind, Perpetuem, HEED or Endura.

Females – you need to carry 350 grams carb (1400 calories)

This could be: 5 gels, 2 energy bars, a sandwich , a banana, and another 100 grams carb in liquid.

Other popular sources: potato, dates, pikelets, lollies, coke

Hydration and Electrolytes on race day

Guidelines: 500 -850mls per hour – depends on your sweat rate, you may need to consider taking salt tablets if you suffer from cramping or sweat excessively.

Some fuel sources contain electrolytes, it doesn’t hurt to add extra .

Fuelling the day before a Long Run – make sure you hydrate (2-3 litres per day) along with salt/electrolytes  – either add salt to your water, or use an electrolyte supplement.   Include carbohydrates such a in your diet 1-2 days prior to a long run. My favourites are sweet potato, potato, beetroot, fruit and white rice. This will ensure your glycogen stores are full, and delay the onset of fatigue.

Private consultation: If you would like some help planning your race day fuel, or help with general nutrition leading up to the day, I am available by appointment in Balgowlah, or via Skype. I also offer body composition testing to assess fat/muscle, cellular health and hydration levels.

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