Endurance Nutrition

If there is one thing that is remarkable about nutrition and sports science it's how incredibly little is known. Considering there is  a lot of possible scaremongering regarding the relationships between exercise, diet rich in carbohydrate and health I decided to look closely at what information is widely available.

Sticking to the subject of diet related to endurance sport I only found one study analysing the diet of elite Kenyan runners - the most successful in the world.  It turns out that without any deliberate or scientific intent they get a whopping 76% of their calories from carbohydrates. Even more surprisingly 20% comes from table sugar that they put into tea with milk. They also get the timing of their eating spot on for replenishing glycogen in the liver and muscles - eating within an hour of exercise. They don't use supplements! In contrast male American endurance athletes only get 46% of their calories from carbohydrates - making up the difference with calories from fats. It appears that runners consume about 3500 calories per day and cyclists around 6500.  No wonder I get tired on long bike rides when I don't remember to eat! I did see one guy race with bananas taped all over his bike frame and handlebars - which was hilarious  - but I think I'll stick to nasty refined supplements thanks.

There appears to be a lot of confusion about whether the top elite athletes are actually damaging themselves or not. The most obvious thing that stands out is that genetics plays a major role, but there is no way of knowing how big a role is played by doping. The chances of then working out the role of nutrition in all of this seems pretty slim - and despite hundreds of universities specialized in sports science and physiology there is apparently no useful or relevant research being done.

You come across vague statements like "top athletes neutralize free radicals and inflammation better than others". Yes, but are there ways to ensure this always happens or can the body be overloaded to the point of gradual destruction? Nobody appears to really know. 

What I would like to know is that if I get my RDA or more of vitamins and minerals in the first 3000 calories of the day - can I eat refined sugar for the next 3500 on the same day (assuming I spend 6 hours in the saddle, cycling) without it being an nutritional issue? Nobody even seems to ask this question. It seems to be how the Kenyans operate instinctively with their sugared tea - but there is no information whatsoever on the long term health of Kenyan athletes. There does not seem to be a single traceable case of heart attack amongst them - but that could be because of genetics or that in the past they couldn't afford doping programs - which after all cost people like Lance Armstrong millions of dollars and almost killed him from cancer. I think I'd place my bet on the latter. It's very easy to get a wide range of banned and dangerous drugs today with complete instructions on how to inject them so more and more Kenyans are now being caught doping - unfortunately. Substances like GW1516 are being consumed by athletes (some cyclists caught recently). This stuff never even made it onto the legal market anywhere due to the cancer it induced in lab rats. People seem willing to abuse their health to extraordinary levels in order to succeed.

Some people suggest that running for elite competition and running for health are different objectives - but that seems like a cop out and a good way of both remaining ignorant and justifying it. People do simply die young in all walks of life - perhaps we just pay more attention when it's an athlete. The medical views on all of this are completely inconsistent. 

Most people will never perform at elite levels or anywhere near that - so it's probably best to keep that in mind. Statistics for endurance sports in general regarding cardiovascular health are extremely favourable. I'm inclined to think that health factors such as obesity, malnutrition and stress are greater indicators of potential trouble. Obesity and malnutrition go together - often the food cravings coming from the absence of quality nutrients. Obesity and lack of exercise also go together - whether it's muscle building or endurance. Exercise is the best way to manage stress too. We also now know that running preserves the length of telomeres (on the ends of chromosomes) that shrink as you age - giving runners an average biological age of 16 years younger than sedentary people. It would seem that anyone exercising regularly (especially endurance - and not at super elite level), avoiding obesity, getting quality nutrients (including fibre) in their overall diet and not doping or taking drugs/alcohol(in quantity) is placing themselves in a large protective zone which, unless there are very rare and unfortunate genetic reasons, should ensure good health throughout a fairly large and flexible range of dietary behaviour. Aiming for strong performance with a high carb diet - with or without supplements - would seem to be well within the zone.

Medical study of heart disease related deaths during marathons (link) :

RESULTS:

A total of 215,413 runners completed the races, and four exercise-related sudden deaths occurred, each due to unsuspected structural cardiovascular disease. Three deaths occurred during the race (after 15 to 24 miles [24 to 38.4 km]) and the other immediately after its completion. The ages were 19 to 58 years (average 37), and three were men. Three of the sudden deaths were due to atherosclerotic coronary artery disease (narrowing of two or three vessels) and one to anomalous origin of the left main coronary artery from the right sinus of Valsalva. None of the four runners had prior documentation of heart disease or experienced prodromal symptoms, and two had previously completed three marathon races each. The overall prevalence of sudden cardiac death during the marathon was only 0.002%, strikingly lower than for several other variables of risk for premature death calculated for the general U.S. population.

CONCLUSIONS:

Although highly trained athletes such as marathon runners may harbor underlying and potentially lethal cardiovascular disease, the risk for sudden cardiac death associated with such intense physical effort was exceedingly small (1 in 50,000) and as little as 1/100th of the annual overall risk associated with living, either with or without heart disease. The low risk for sudden death identified in long-distance runners from the general population suggests that routine screening for cardiovascular disease in such athletic populations may not be justifiable.

Since taking up road cycling racing several years ago I’ve noticed that people do die regularly – but normally when going very fast downhill and coming off the road. Despite being in gruelling races with 17,000ft of climbing at high altitude, with several thousand entrants, I’ve not heard of a single death from heart disease – though a lot do end up with saline drips and oxygen in the med tent. Compared to downhill skiing where avalanches are a constant and relatively unpredictable threat the attrition rate is very small.