Non-carb diet for running

Do the instructors who run this fitness course eat carbs?

I bet you six jacket potatoes and a mountain of pasta they do!

No carbohydrates?! NO CARBOHYDRATES??!! What kinds of sick weirdos are these people??! *Goes off for a lie down*

Some of these personal trainers make me so mad.I know some of them are good and do know what they are talking about, and i'm certainly no training expert, but a few I have heard of see to talk absolute bollocks.

There is a young woman who runs in the same pack as me at the club. She is always flaking out in the runs and the pack leader has to run back for her but she refuses to move down into a slower pack. Yesterday she was talking about her training and it became apparent why she is having these issues. She is eating a very low carb diet on the advice of her 'trainer' from this poncey over priced gym. The 'trainer' is not a runner but has done 'a few' triathlons. The trainer also has her doing a 3.5 hour run the day before a 2 hour run with hills. Some of the really experienced runners in the club have tried giving her advice and telling her that this is absolute madness but she just won't listen and is convinced this trainer is right.

She is convinced she will be running a sub four hour marathon in three weeks despite almost passing out yesterday after 20k in two hours. I just hope she doesn't get really hurt. It was really scary seeing her yesterday in that state and totally in denial.

hlith - maybe if your mate does this mara and ends up poorly she'll understand what you've all said - does her

Its a very naive attitude though, why don't people realise - you're running a long way you need ENERGY

What a load of bollix. Snippets of truth all bundled up in a whole load of pseudo-scientific crap.

Here goes my take on things:

"If this was true then how can body builders get so lean whilst only expending 300 calories in their workouts but eating around 5000 calories per day? The answer lies in our hormonal response to exercise and the effect it has on our metabolism"

The answer actually lies in the body composition of a body builder. Having much, much more metabolically active tissue (muscle), the basal metabolic rate of a body builder will be much higher than someone who has less metabolically active tissue, i.e. a distance runner. The answer also lies in the fact that they expend more than 300 calories a day - by doing everything else they do other than their workout.

The hormonal response to 1,000 calories of carbohydrate is very different to the hormonal response to 1,000 calories of fat or protein. The body is made from fats and proteins where as carbohydrates are used for fuel. Therefore unless you are an endurance athlete your body has a greater need for fat/protein than carbohydrate and any excess will be stored as body fat.

The hormonal resopnse IS different. That bit is true. Carbohydrates are used for fuel, that is also true. As are proteins and fats, depending on the intensity and duration of any activity. However, endurance athlete or not, your body has a need for all macronutrients. Any activity requires fuel - even being conscious requires energy. The fact of the matter is, your body has a need for sufficient energy - it will find it from one source or another, and if surplus is eaten and a person is sedentary that excess tends to be stored as fat.

A low cholesterol diet will give me low blood cholesterol… 1. Cholesterol is absorbed in the lymph so blood cholesterol is not related to dietary intake of cholesterol. 2. Blood cholesterol is manufactured by the liver from carbohydrates. So low carbohydrate diets will reduce blood cholesterol.

1. Cholesterol is transported both in the lymphatic system, and in the blood (where it is bound to a protein). Research into the impact of dietary cholesterol on plasma cholesterol does seem to suggest that dietary cholesterol has little impact on plasma cholesterol. However, dietary fats (saturated and trans in particular) does have an effect on dietary cholesterol.

2. Cholesterol is manufactured in liver, and there are tight homeostatic controls to maintain an adequate supply of cholesterol, because it is vital to various physiological functions. This cholesterol is manufactured from a compound called aceytyl CoA, which is a product of both carbohydrate and lipid metabolism. So whilst a lower carbohydrate diet may reduce blood cholesterol (there is actually some evidence to coroborate this), the diet as a whole is a far more important determinant.

Saturated fat causes cancer and obesity… This is true if you don't have a healthy digestive system - or if you eat non - organic meats.

Quite frankly, what the hell?  So you can have a BMI of 70, but as long as your digestive system is healthy and/or you eat organic meat, this ameliorates the effect of obesity and saturated fat on cancer risk? Um, no...

I cannot stand this kind of pseudo-science nonsense. It's irresponsible and if taken seriously, potentially dangerous.

But getting back to the main point, yes, you do need carbs for marathon running.

Annoyed rant over

"But getting back to the main point, yes, you do need carbs for marathon running. "

Lol Sarah!!

Alun

There are guideline amounts (from the IOC, IAAF, and others) for protein, carbs and fat levels for training and performance. Failure to replenish carbs after energy expenditure leads to muscle glycogen depletion, which reduces capacity to produce energy both anaerobically and aerobically. Carbs should be mainly low GI, except for refuelling straight after heavy exercise (if exercising again within about 24 hours). For weight loss, calorie intake should be about 15% below maintenance level (i.e. small deficit), preserving required levels of protein and carbs. Fats should be mainly healthy fats (little saturated, very little trans fats).  Fibre, vits and mins, long-chain omega three (i.e. fishy ones), and sufficient fluids are required. Antioxidants may be helpful for health and exercise, but in any case fruit and veg are good because they contain vits and mins, low GI carbs (usually), and fibre.

As far as I can see, from a bit of reading, that's really it as far as the basics of nutrition and exercise go. It's not very exciting, but it seems to be based on lots of research and agreed by (real, genuine, trained, clever) scientists. I'd recommend Anita Bean's "Sports Nutrition" to your friend if she wants to get some sane, evidence-based guidance.

Alun - frankly, the advice given to your friend on the surface seems so stupid, that I honestly can't believe it is the full story. There must be some other context or caveats to what they were saying. Having a "wild metabolism" is just marketing-fluff-talk, but OK, it can be sniffed from a distance.

Perhaps your friend had mentioned some other objectives such as lowering cholesterol, body fat percentage etc, and the 'wild advice' was directed towards that? It's certainly true that not all calories are equal (otherwise we'd all be having pre-marathon beer drinking sessions) (actually, that might numb the pain a little!).

There are times when I might consider doing a long run and backing off the carbo-load beforehand. I'd certainly choose complex carbs over simple sugars before a long run. But a simple, unbounded statement like stick to a non-carb diet is so far off the mark when it comes to marathon preparation. Any ('non-wild') running nutrition book will tell the same story. Carbs aren't optional - they are absolutely essential.

The body is also capable of metabolising fat or catabolising proteins to fuel energy systems, but always after the principal energy system (glycogen) is heading towards depletion. Glycogen is provided through carbohydrates. Any attempt to run post glycogen depletion will be more painful, more slow and less enjoyable. Spread that out over a whole marathon training programme and you will have a weak, demotivated, slow runner who is more prone to injury and probably accidents too (guess what, the brain is primarily fuelled by glycogen!).

Well done for being a good friend Alun and challenging the cr4ppy advice she is being given.

"If this was true then how can body builders get so lean whilst only expending 300 calories in their workouts but eating around 5000 calories per day? The answer lies in our hormonal response to exercise and the effect it has on our metabolism

No,the answer lies in the consumption of steroids - mind you for all the good they did me I might as well have stuck them in my arse.

If she carb loads before the race and her training has progressed ok up until then, she will probably do quite well during the race because she'll have a lot more ready energy than she's used to. However, I still think it's a stupid idea and likely that her training will suffer quite seriously to the point where she won't be able to get enough mileage in before the event.

You can only offer an opinion though, if that's what she's set on doing, let her get on with it.