Sunday, 27 September 2015

LCHF and endurance riding - Part 3

LCHF adaption can play a huge part in endurance performance. By reducing carb intake you reduce the insulin loading and allow the cells to better absorb and metabolise fat. But this takes time. It's not an overnight switch. It can take weeks or months. Once you are adapted, a byproduct of all the extra fat metabolisation is the production of excess ketones which the brain is happy to feed on.
It stands to reason that if you are able to metabolise fat and produce ketones you don't have a deadlock where the two key components of performance, namely, muscles and your mind, are competing for the same resource.
In practice, since adapting the LCHF lifestyle, I have had instances where I have maxed out physically due to poor training but have never had the mental collapse normally associated with bonking.
In multi-day endurance events it is unlikely that you function in an elevated heart rate zone for an appreciable time. It general you have short bursts of elevated heart rate effort.
My question, to which I have no answer to as yet, is as follows: once you are several days into an endurance race how is your exertion in terms of HR zones defined. Are the zone HR rates remain at the rested state zones or does it shift down as your condition declines and your heart rate follows?
I must point out that hearts don't get tired in the sense that your heart rate drops because that organ get exhausted from the exercise. Sure, the heart is a muscle and does get stronger with exercise. As a conditioned athlete athlete your heart rate is defined by the oxygen demands of the body. If you recruit significant muscle mass you need more oxygen and your heart responds by delivering more oxygenated blood to meet the demand. That being the case, it follows that your HR Max is particular to an activity. Swimming, running, cycling and cross-country skiing will yield very different results.

We will assume that our endurance efforts take place in a lowered heart rate effort which facilitates aerobic metabolism. That being the case you are well within the fat burning exertion zone so should have sufficient fuel in the form of fat to supply your energy needs.
A quick word about carbohydrate and fat reserves. The tried and tested method of carbo-loading before a big event will store away only 5k calories of race fuel reserve. Probably enough for a 5 or 6 hour ride. Our body fat stores in excess of 80k. And that's a super lean athlete. I probably have twice that tucked away.

Yesterday I completed a 38 hour non-stop bike race and burned something in the order of 22k calories. If I wasn't fat adapted I would have run out of steam very quickly. I would need to keep fuelling on carbs to keep pace with the rate of burn. As it was, I hardly ate anything and finished the race firing on all cylinders. As a rough estimate I would think I ate food somewhere in the region of 6-8k of calories. Huge deficit if not fat adapted.

So, the bottom line — what do I eat while racing in multi day endurance events. The short answer is "anything". I used to like a mixture of Coke and water in my bottles. Off the bike I never drink Coke. On the bike I used to like it. When I started the most recent race 2 days ago I put Coke and water in my bottles and I didn't enjoy it like I used to. I eventually switched to just water. I added the occasional sachet of electrolytes or use the effervescent tablets that do the same thing. But I got sick of that taste and made a point of drinking that separately and keeping plain water in my bottles. I used to eat gelatine based soft chews; jelly babies and wine gums. I managed to get through just one roll of wine gums. I took snack bars and a handful of nougat based race snack bars and didn't use any of them. I seems I have gone off sweet things completely.
I just want normal food. I had a hamburger and didn't eat the bun. Not my cup of tea it seems.
Does it work? I won the race. That's sufficient evidence.

Given the nature of the races I do it is an impediment if you are on a strict diet. I eat whatever I can get my hands on but choose LCHF options if they are available.
To be fair, I haven't done any events in excess of four days since switching to LCHF so have no experience of what the effects are of dropping out of a fat adapted state due to an increase in carb input. My experience in events up to 4 days is that my metabolism doesn't appear to change in any noticeable way.
To wrap this up let's look at the incident of 2010 where I bonked an hour into day 2 of an event and compare it to the race I did in June this year without training for.
In 2010 I wasn't on LCHF and did the normal carbo-load thing. Clearly it didn't work. I was trashed and my mind went tilt. In June this year after a 3 month layoff due to injury I was a last minute entry in a 500km race. 8 hours in my lack of condition was evident. But my mind was as sharp as a pin. I knew exactly what the challenges were and managed to deal with the issues and went on to win the race. That I think is a big difference. If you can keep your head space intact you can deal with the issues. By being fat adapted I think bonking is a thing of the past. I can't make that statement with absolute surety but can say I haven't bonked since switching to LCHF.

Thursday, 24 September 2015

LCHF and endurance riding - Part 2

Hitting the wall (a term used in running parlance) or bonking (cycling terminology) describes a condition where the body runs short of stored glycogen resulting in extreme physical fatigue often accompanied by reduced mental facility. The mental impairment ranges from wanting to give up to symptoms consistent with hypoglycaemia (low blood glucose) such as confusion and hallucinations.
I have experienced this condition on three occasions. Once while running and twice on my bike. The bike incident in 2010 was the interesting one because it came an hour into my second day of an event. I wasn't riding particularly hard but I was tired. I wasn't in race condition and as it was a social ride I planned to take each day slowly. At the end of day one (a 12 hour effort) I was shattered and my exhaustion made eating a schlep. I only managed a small helping of dinner and had an equally small portion for breakfast. The result was that I didn't build up my glycogen reserves and an hour into the second day I bonked. I sat next to the trail staring at my bike convinced there was something wrong with it. I didn't want to talk to anyone else. I was simply miserable. Having experienced the condition previously I knew what needed doing and started stuffing food down my throat. Particularly food high in sugar. I continued dribbling down the trail and after 2 hours the lights came back on and I was able to continue normally.

So what does this incident have to do with LCHF? A lot actually. Pin this incident to your mind as we are going to use it a bit later in this discussion. We will label it 'The incident of 2010'.

A few words about muscle fuelling. Again, I am no expert. We store glycogen in our muscles and liver. If we engage in high energy activities with a heart rate in excess of 65% of our heart rate reserve (HRR, the usable heart rate between resting and max) we drawn heavily on these reserves and they begin to deplete. Glucose is then drawn from the blood to replenish these reserves, which, it not supplemented by refuelling with carbs, will lead to low blood sugar and bonking as your brain and your muscles start wrestling for the dwindling reserves.

As I understand it, our muscles are capable of being fuelled by glucose, fatty acids and ketones. Ketones, as stated earlier are produced when we metabolise fat. The brain can use either glucose or ketones as a fuel. It is suggested that ketones are the brain's fuel of choice.
Excessive use of carbohydrates leads to massive doses of insulin being released into our system. Is is claimed that insulin has the effect of reducing our cells ability to fuel off fatty acids or ketones making them dependant on glucose.
Endurance endeavours generally take place at lower levels of exertion and are better suited to fat metabolisation. Thats fine if your body hasn't been hammered by carbs which results in a reduced ability to process fat instead of glucose.
This explanation is simplistic but Is the gist of it.
Next up, LCHF adaption....

Sunday, 20 September 2015

LCHF and endurance riding - Part 1

I have been asked to elaborate on my experience with LCHF and endurance riding.

From the outset let me be clear. I am not an expert in nutrition or the science of sports performance. In many ways my methods are laughable, but they work for me.

My endurance successes are moderate. Sure, I have won a race and placed second and third in my last 3 non-stop 500-600km events. But these are small races in that they are not run of the mill and attract a niche crowd. Crowd is an exaggeration. A handful or two would be more correct — Let's settle for 50. In the longer 2200km format my best finish was 5th. However, in my last 2200km event I had not yet switched to a LCHF lifestyle. My best race results have been over the last 2 years after I switched to LCHF. I have focused on the 500-600 km events of late.

What follows is the experiences of a layperson. They are my experiences — not hearsay, not secondhand.

My best result, as far as physical performance is concerned was Race to Rhodes 2014; I placed third - funny story. In 2015 I won the event even though I rode it 17 hours slower - equally funny story. These two races are significant in my understanding of how I have adapted to a LCHF diet under race conditions. We will examine this in more detail later.

To understand the effects of LCHF on race performance we need to understand the base diet and degree of dietary adaption of the athlete. The switch to LCHF begins many months or years before any race event. It entails a change of lifestyle. I am not hyper-strict. I don't weight my food and I don't read all the labels. To keep it simple we eradicated a few things from our household diet — Sugar (or anything containing vast amounts such as soft drinks, drinking chocolate, cake, etc.), Bread, Pasta, Rice, Cereals and Potatoes — basically all the carbohydrate bombs. We then switched to full fat milk and stopped shying away from cheese and animal fats. Margarine was shunned and was replaced with butter.
We aren't big on compensating for low carbs by ratcheting up our fat intake, we just don't avoid fat. We select full cream yoghurt and enjoy chicken skin and the fat on joints of meat. It's important to note that the eating plan is low-carb and not no-carb.
Before I started on LCHF I had slightly elevated cholesterol. But that was in the combined LDL+HDL. My HDL has always been well above my LDL reading which is considered good. Over the last year my cholesterol levels have dropped nearly 10%. Sure, that isn't everyone's experience but it is mine. Tests were done clinically and not at the local pharmacy.

My weight over the last 2 years has dropped by 14kg's. Nothing dramatic, just a slow steady decrease. At the start I was probably 10kg's above a reasonable weight due to a riding injury that kept me off my bike for a year. The last 4 kg's are as a result of an increased training regime without a commensurate increase in food intake.

The first noticeable difference is that I am never hungry. Eating becomes a function rather than a craving. I have to remember to eat. I believe the lack of hunger is as a result in stable blood sugar levels. By controlling sugar spikes you avoid excessive release of insulin which in turn causes sugar levels to drop which I am told trigger feelings of hunger. As a test, a friend and I rode in a fasted state (no breakfast, just a glass of water) for 3 hours and then tested our blood sugar levels. Our findings showed that although we had ridden hard for 3 hours our blood sugar levels reflect completely normal levels. Our conclusion was that we were not fueled by sugar but rather by ketones released by metabolising fat in the absence of carbs. We reasoned that had we been using carbs as fuel our sugar levels would have been lowered due to the extended period of sustained exercise without a replenishing supply.

What does all this have to do with performance while competing in endurance events? A lot actually. We will get into that in the next update.